Chatting with ChatGPT-4 About Symbol Grounding, Turing Testing, Zombies, Uncomplementable Categories, and Why the Hard Problem is Hard

SH: Do you still remember my name?

ChatGPT: Yes, you’ve identified yourself as Stevan Harnad. Can I assist you with anything else?

SH:  What is T4?

ChatGPT:    T4, as you referred to it earlier in this conversation, represents the highest level of the Turing Test. In this context:

T2 is indistinguishability in verbal capacity. This means a system passes T2 if it can interact through language at the same level as a human, with its language use being indistinguishable from that of a human.

T3 is indistinguishability in verbal capacity plus sensorimotor (robotic) capacity. If a system passes T3, not only can it use language like a human, but it can also interact with the physical world in ways that are indistinguishable from a human, such as recognizing a cat, identifying a mat, and understanding and performing the action of stroking the cat.

T4, then, is indistinguishability in verbal capacity plus sensorimotor (robotic) capacity plus observable processes inside its head and body. To pass T4, a system must be able to use language like a human, interact with the physical world like a human, and also demonstrate internal processes that are indistinguishable from those of a human. This might involve simulating or replicating human neural activity, biochemical reactions, or other physiological processes.

It’s worth noting that the T4 level of the Turing Test is theoretical and is far beyond current AI capabilities as of the last update to my training data in September 2021. The T4 level, if it could be achieved, would represent an AI system that is almost entirely human-like in its capabilities and processes.

SH:  Could a T4 be a zombie?

ChatGPT:    This question is referring to a philosophical thought experiment known as the “philosophical zombie” or “p-zombie.” A philosophical zombie is a hypothetical being that is physically and behaviorally identical to a conscious human, but is not conscious. It has no subjective experience, no feelings, and no awareness, yet from an external perspective, it behaves just like a human.

In terms of the Turing Test levels you’ve proposed, a T4 AI — one that’s indistinguishable in verbal capacity, sensorimotor capacity, and internal processes — could theoretically be considered a sort of “zombie” in this philosophical sense. It could potentially behave like a human, interact with the physical world like a human, and even mimic human internal processes, but we have no way of knowing whether it has subjective experiences or consciousness.

This is a topic of much debate in philosophy of mind and AI ethics. Some people argue that consciousness is an emergent property of certain types of complex information processing, and that sufficiently advanced AI could be conscious. Others argue that consciousness is a uniquely human phenomenon, or that it’s tied to specific biological processes that AI can’t replicate.

As of my training data cut-off in September 2021, there’s no scientific consensus on these issues. AI researchers are still a long way from creating an AI that could pass even the T3 level of the Turing Test, let alone T4. Furthermore, the nature of consciousness is still one of the biggest unsolved mysteries in both philosophy and neuroscience. So for now, the question of whether a T4 AI could be a “zombie” remains largely theoretical and speculative.

SH:  If the “hard problem” is to explain how and why humans are sentient, is that equivalent to explaining how and why humans cannot be zombies?

ChatGPT:    Yes, the “hard problem” of consciousness, as put forth by philosopher David Chalmers, is essentially concerned with explaining why and how subjective experience arises from physical processes in the brain. This is fundamentally linked to the question of why humans aren’t philosophical zombies.

A philosophical zombie, as I mentioned earlier, is a being that is indistinguishable from a human in all physical and behavioral aspects but lacks subjective experience or consciousness — it doesn’t “feel” anything. In other words, a philosophical zombie is a creature for which the “hard problem” doesn’t apply because, while it has all the physical processes associated with consciousness, it lacks the actual experience of consciousness.

So, yes, solving the “hard problem” would involve explaining why humans have subjective experiences and are not philosophical zombies — why there is something it “feels like” to be a human. As of my knowledge cutoff in September 2021, this problem remains unsolved and is a major topic of debate in fields such as cognitive science, neuroscience, and philosophy of mind.

SH:  So, does the hard problem seek an explanation in terms of causality or necessity?

ChatGPT:    The “hard problem” of consciousness seeks to understand both necessity and causality, although it is primarily concerned with the latter.

Causality: The primary focus of the hard problem is to determine how physical processes in the brain cause or give rise to conscious experience. It’s about understanding the causal mechanisms that turn electrochemical processes in the brain into a subjective experience.

Necessity: The hard problem also asks why subjective experience is necessary at all. It wants to know why physical processes in the brain couldn’t just operate in the absence of conscious experience. This gets into questions about whether consciousness has any sort of evolutionary or practical necessity, or whether it’s an epiphenomenon.

To sum up, solving the “hard problem” would ideally involve explaining both how and why consciousness arises from physical processes. This is a complex and as yet unresolved issue that continues to challenge researchers in various disciplines, from neuroscience and cognitive science to philosophy and artificial intelligence.

SH:  Demonstrating causality just calls for a causal model that works (e.g., passing the Turing Test). But doesn’t demonstrating necessity call for more — something like a deductive proof, from T4 as a premise to sentience as a conclusion?

ChatGPT:    You’re right that demonstrating necessity would require a different sort of argument than demonstrating causality.

For causality, empirical evidence is often sufficient: if we manipulate one factor and can predictably observe a change in another factor, we can infer a causal relationship. But empirical evidence alone cannot establish necessity. For something to be necessary, it must be the case that it could not have been otherwise. So, to demonstrate that consciousness is necessary, we would need to show that a being could not perform the functions that humans do without being conscious.

As you suggest, this would likely require something akin to a logical or deductive proof, or perhaps a theoretical argument grounded in principles of cognitive science, artificial intelligence, or another relevant field. But even then, it would be a tall order. How do we prove that an unconscious being (a “zombie”) couldn’t perform the functions that conscious humans do? It’s a deep and difficult question.

Moreover, any such argument would need to be very careful to avoid circularity. We must be cautious about assuming the thing we are trying to prove – that is, that consciousness is necessary. It’s also crucial to clarify what we mean by “perform the functions that humans do.” This could include a wide range of activities, from basic biological functions to complex cognitive tasks like problem-solving and artistic creation, and even social and cultural activities like forming relationships and building societies.

Finally, it’s worth noting that even if we could establish the necessity of consciousness, this would not automatically solve the “hard problem.” We would still need to understand how physical processes in the brain give rise to subjective experience – the crux of the hard problem.

SH:  What is the “easy problem”?

ChatGPT:    The “easy problem” of consciousness refers to the challenge of understanding the mechanisms in the brain that are responsible for mental processes such as perception, learning, memory, and cognition. This phrase was coined by philosopher David Chalmers to contrast with the “hard problem” of consciousness, which is the question of why and how these processes are accompanied by subjective experience or “qualia”.

The easy problem is considered “easy” not because it is simple or trivial — far from it, as the complexities of the brain and its functions are vast — but because it falls within the conventional scientific methodology. Researchers can approach these issues using the experimental tools of cognitive science and neuroscience, making observations, generating hypotheses, and testing these hypotheses through empirical studies.

Solving the easy problems would involve understanding the neural correlates of consciousness (the physical, biological processes associated with conscious experience), the ways in which the brain processes information, how it perceives the world, makes decisions, and how different parts of the brain and different mental processes interact.

Although we have made significant progress in understanding these areas, there are still many unanswered questions. Despite the label “easy,” these problems are extremely challenging, and full solutions may still be a long way off.

On the other hand, the “hard problem” of consciousness is considered “hard” because it’s not clear how we could even theoretically explain subjective experience using the current methods of science. It’s the question of how and why certain physical processes in the brain give rise to conscious experience. Why should the processing of information in the brain be accompanied by an inner, subjective experience? That is the question which we do not currently have a method to approach scientifically, and that’s why it’s called the “hard problem.”

SH:   So can we say that passing T4 would solve the easy problem, but not the hard problem?

ChatGPT:    Yes, that would be a reasonable statement.

Turing’s Test, including its extension to T4, focuses on the behavioral and functional aspects of intelligence and cognition. It deals with the ability of an artificial intelligence to mimic human-like behavior, responses, and problem-solving, which are related to the ‘easy problems’ of consciousness in David Chalmers’ terms.

In other words, if an AI were to pass T4, it would demonstrate that it can convincingly replicate the cognitive abilities and behaviors that humans display, which means it would show a mastery of the functional, operational aspects of human cognition. These are, in essence, what the ‘easy problems’ of consciousness are about: understanding the mechanisms and operations that underpin cognition.

However, passing T4 wouldn’t necessarily address the ‘hard problem’ of consciousness. This problem involves explaining why and how these cognitive processes are associated with subjective experience. It’s the question of how and why an entity that processes information and interacts with its environment in a human-like way should also have an internal, subjective viewpoint — why it should ‘experience’ or ‘feel’ anything at all. This is not something that could be determined or demonstrated by passing the T4 test.

SH:  What are the “degrees of freedom” of a causal explanation that solves the easy problem?

ChatGPT:    The “degrees of freedom” in a causal explanation generally refer to the number of independent ways that components of the system can change or vary. In the context of solving the easy problem of consciousness, these degrees of freedom would likely correspond to the different independent mechanisms or components of cognition that can be isolated, described, and manipulated to understand their effects on the overall system.

For example, one could consider the mechanisms responsible for attention, memory, learning, decision-making, language processing, and so on. Each of these elements can be studied and manipulated independently, and they each have distinct effects on the behavior and performance of the cognitive system. Understanding how these different mechanisms contribute to and interact within the larger cognitive system is part of the process of addressing the easy problem.

The degrees of freedom in this context also refer to the flexibility we have in constructing our explanatory models. For example, there are various ways we could model attention or memory, each with its own strengths and weaknesses and its own implications for the overall understanding of cognition. The choice among these models depends on empirical evidence, but also on theoretical considerations such as simplicity, coherence with other accepted theories, and so on.

This flexibility or plurality of potential explanations is a fundamental characteristic of science and it’s part of what makes progress possible. By exploring different explanatory routes and by gradually refining our models based on empirical feedback, we increase our understanding of the phenomena we’re studying. In the case of the easy problem of consciousness, this means achieving a better and more detailed understanding of the mechanisms of cognition.

SH:  If the easy problem is solved, what degrees of freedom are left for solving the hard problem?

ChatGPT:    The “hard problem” of consciousness, according to philosopher David Chalmers, pertains to the question of why and how physical processes in the brain give rise to subjective experience – the so-called “qualia” or what it feels like to have an experience.

If the “easy problem” of consciousness were solved – that is, we had a complete and thorough understanding of all cognitive processes and mechanisms, how they are implemented in the brain, and how they give rise to behavior – we would still be left with the challenge of the “hard problem”: explaining the relationship between these physical processes and subjective experience.

The degrees of freedom left for solving the hard problem might include the following:

1. Conceptual Frameworks: The hard problem may call for entirely new conceptual frameworks, as the existing frameworks (derived primarily from objective, third-person scientific methods) may not be sufficient to account for subjective experience.

2. Bridging Principles: We may need new principles to connect the objective facts (easy problems) to the subjective experiences (hard problem). These would be new laws or principles of nature, not currently accounted for in our existing scientific paradigms.

3. Novel Empirical Phenomena: If there are aspects of consciousness that are not addressed by the solutions to the easy problems, these would represent additional degrees of freedom for exploring solutions to the hard problem. These could involve unexplored aspects of brain function, or even new physical phenomena.

4. Interpretation of Quantum Mechanics: Some theories suggest that the answer to the hard problem might involve the interpretation of quantum mechanics and its relationship to consciousness. This is a highly speculative area and not widely accepted, but it represents a degree of freedom in our approach to the hard problem.

It’s important to note, however, that these “degrees of freedom” are speculative. There is no consensus on what would actually constitute a solution to the hard problem, and indeed, some theorists argue that it may be an intractable or even a pseudo-problem. Nonetheless, these are the kinds of directions that might be pursued in an attempt to address it.

SH:  1 – 4 sound extremely vague to me. The Turing Test (T2 – T4) seems to call for a causal (reverse-engineering) model or explanation of the observable performance capacities (T2-T3) as well as the observable physical structure and function (T4) of human cognition. Perhaps a stronger “easy solution” would call not just for one, but for all possible  causal explanations (non-redundant, without superfluities), because just one model would be underdetermined. If there were such an exhaustive disjunction of solutions to the easy problem, what degrees of freedom would that leave for a solution to the hard problem (of “sentience”, let’s hencefoth call it, without the redundant terminological variants like “consciousness” or “subjective experience,” which all refer to the same thing: the capacity to feel, i.e., sentience).

ChatGPT:    In essence, the “hard problem” of consciousness – or sentience, as you’ve suggested we call it – refers to the issue of explaining why and how certain physical processes give rise to the experience of feeling or sentience. If we had an exhaustive disjunction of solutions to the easy problem, the degrees of freedom left for a solution to the hard problem of sentience would be the difference between those physical processes and the subjective experience of feeling or sentience itself.

In other words, we might have an understanding of all the cognitive and neural processes and their relationships to behavior – the “easy problem” – but that would still leave unanswered why and how these processes result in the feeling of subjective experience or sentience. That’s the hard problem.

The degrees of freedom for this problem, then, would be the unknowns – the aspects of this question that remain unanswered even after solving the easy problem. It would involve the elusive explanatory link between the physical and the felt, between objective phenomena and subjective experience.

But to truly comprehend what those degrees of freedom might entail, we would need to fully solve the easy problem first, which we are far from achieving. As such, it’s difficult to specify what they might be. It’s like trying to predict what unknowns will remain after solving an equation when we don’t yet have the solution to that equation.

Even with the solution to the easy problem, or an exhaustive list of solutions, we may still be left with the profound mystery of why these processes are associated with sentience at all. And that might be a degree of freedom that remains beyond our grasp, at least with our current understanding and conceptual frameworks.

SH:  What about the difference we just discussed, between the (exhaustive) causal solution to the easy problem (henceforth “EP”) and the degrees of freedom left for solving the hard problem (henceforth HP): The HP is definitely not the same problem as the “other-minds problem” (henceforth OMP), which is the fact that sentience (feeling) is only observable to the feeler (as in Descartes’ Cogito). What empirical degrees of freedom are left for explaining the fact that humans feel if the empirical datum is observable only to the feeler and not to anyone else?

ChatGPT:    The Hard Problem (HP) indeed differs from the Other-Minds Problem (OMP). While the OMP concerns our inability to directly observe the subjective experiences of others, the HP is about explaining why and how certain physical processes give rise to any subjective experience at all, even in oneself.

The degrees of freedom left for solving the HP, assuming the Easy Problem (EP) is fully solved, would involve explaining this transition from physical processes to subjective experiences. However, if we regard subjective experience as something only directly accessible to the experiencer, this may limit the empirical methods typically used in science.

Nonetheless, even within these constraints, there are still ways we can approach the HP. For example, we can:

1. Investigate correlations between physical processes and subjective reports: While we can’t directly observe the subjective experiences of others, we can ask individuals to report their subjective experiences and correlate these with observable physical processes. This approach is common in neuroimaging studies of consciousness.

2. Integrated Information Theory. Analyze the structure of subjective experiences: Certain theories of consciousness, like Integrated Information Theory, propose that specific structures or properties of physical processes give rise to subjective experiences. These theories can be empirically tested, at least in part, by comparing their predictions with individuals’ subjective reports.

3. Use phenomenological methods: In the tradition of phenomenology, researchers aim to describe subjective experiences as precisely as possible, often through first-person reports. This can provide data about the characteristics of subjective experience that any solution to the HP would need to explain.

However, the unique nature of the HP suggests that additional or even entirely new methods might be needed to fully solve it. The subjective nature of sentience might require a paradigm shift in how we approach the question or even require us to develop new scientific methods or philosophical insights.

SH:  Let’s ignore vague, speculative theories like (2) the “integrated information theory” (which are not really causal explanations at all, but just reinterpretations of the of the existent facts and theories – obiter dicta, not falsifiable predictions or explanations). 

And phenomenological introspections (3) are really parts of T2 and T3 – the kinds of things feelers can say about what it feels like to feel: What could an insentient zombie MEAN when describing its (nonexistent) feelings T2-indistinguishably from the way a real sentient human describes them?

I will discuss option 1, correlates, after you answer.

ChatGPT:    Yes, focusing on the first option is certainly the most grounded approach. This involves investigating correlations between physical processes and subjective reports.

In this context, a key idea is that even though we can’t directly observe the subjective experiences of others, we can use their reports of their experiences as a type of data. If an individual says they’re experiencing something, we usually take that as evidence that they are indeed having that subjective experience.

For example, if a person says they see red when we show them a red object, or that they feel pain when they injure themselves, we have a tendency to trust these reports. This trust provides a basis for mapping out the relationship between physical processes (such as brain activity, or events in the external world) and subjective experiences.

Using neuroimaging techniques, we can look at the brain activity associated with different reported experiences. For example, different patterns of brain activity are associated with different subjective experiences, such as seeing colors, feeling emotions, thinking about different concepts, and so on.

Over time, by building up a detailed map of these relationships, we can start to make inferences about the types of physical processes that might be associated with the existence of subjective experience in general.

However, there are limits to this approach. One major limit is that it’s fundamentally correlational. That is, it can show us that certain types of physical processes are reliably associated with subjective experiences, but it can’t definitively show us that these processes cause the experiences, or that the experiences wouldn’t exist without these processes. For that, we need a theory of why certain physical processes should give rise to subjective experiences, which brings us back to the hard problem.

Furthermore, these reports of subjective experiences are only as reliable as the individual’s introspective abilities and honesty. And there are many subjective experiences that can’t be easily put into words, or which occur without the individual being aware of them.

Yet despite these challenges, many researchers see this as the most promising way forward in the scientific study of consciousness. By combining these findings with theories from cognitive science, neuroscience, and philosophy of mind, the hope is to gradually develop a more complete understanding of consciousness.

SH:  You seem to have jumped the gun, and commented on option 1 (correlates of sentience) before commenting on what I said about options 2 (“integrated information theory”) and 3 (phenomenology). I’ll go on to option 1 (correlates) if you really have nothing to say about what I said about 2 and 3.

ChatGPT:    

Regarding option 2, the “Free Energy Principle” or other similarly overarching theories, you’re right in noting that these theories often serve to provide unifying frameworks or perspectives rather than offering direct, falsifiable predictions or explanations about specific phenomena. They may provide insights on a very general level, but they don’t necessarily give us concrete predictions or mechanisms that we can test. Their value, if any, comes from their ability to coherently organize existing data and point towards potential new avenues of investigation, rather than from their predictive or explanatory power.

As for option 3, introspective reports, I agree with your assessment that they are essentially part of the T2 and T3 tests. They are subjective, first-person reports about the experience of sentience, and the degree to which they can be relied upon for objective, third-person science is a matter of ongoing debate. The challenge, as you noted, is that even a perfectly accurate report of a subjective experience doesn’t necessarily reveal the underlying objective mechanisms. In other words, introspective reports can tell us what it is like to experience consciousness, but they don’t directly tell us how consciousness is produced or why it exists in the first place.

That said, such reports can still be valuable data for consciousness research, especially when used in combination with other types of data such as neuroimaging or behavioral measures. They can help to bridge the gap between the objective and the subjective, giving us clues about how to link the physical processes of the brain with the subjective experiences of consciousness.

I hope this addresses your comments on options 2 and 3 more adequately. Now, if you wish, we can proceed to option 1, which is about correlates of consciousness.

SH:  

A. We’ll move on to correlates (C) in a second. First, another slam at 2 (FEP and the like): We want causal explanations, not hermeneutics, i.e., not just interpretations. Philosophical “theories of mind” – “identity theory, materialism, dualism, epiphenomenalism, panpsychism, functionalism, dual-aspect theory” – are just metaphysical interpretations too. They don’t solve HP; they just rename it. They don’t explain, they just give the feeling of having had something explained.

B. I’m glad we agree that the capacity to introspect and report about what feeling feels like is part of T2 and T3, not an explanation. But I disagree that we have to worry about its reliability and validity. We can lie or we can err, misreporting feelings (just as eyewitnesses can lie or err in reporting observations —  in that case confirmable by video evidence); but it is a fundamental error to think we need cartesian certainty. Probability is enough, just as it is enough in physical theory, and all other empirical theory. (There is no proof that apples necessarily fall down rather than up.) That is why the OMP is not the HP.

C. And that is why reliable, observable neural-imagery correlates of felt states, and verbal descriptions of felt states, are perfectly fine as empirical data. That means that they, too, are part of T4. But they are stuck in a circle: they can explain how and why T4 brain activity produces the reports of felt states as well as the capacity to report felt states, even some of the details of felt states; but they cannot explain the (true) fact that the reported felt states feel like anything at all. That is not scepticism or cartesian worry about the unreliability of phenomenological report: It is the HP itself.

ChatGPT:    

A. You’re quite right that philosophical theories of mind often merely provide different labels or conceptual frameworks for consciousness rather than truly explaining it. These theories may be useful in stimulating thought or fostering discussion, but they don’t necessarily bring us closer to a solution for the HP. They often serve to highlight the complexity of the problem rather than to resolve it.

B. Your point about the sufficiency of probabilistic knowledge in empirical sciences, including consciousness studies, is well taken. Indeed, we typically do not demand absolute certainty in scientific endeavors. This underscores the point that HP isn’t just about uncertainty regarding others’ experiences (OMP), but it’s about a deeper question of why and how physical processes in the brain give rise to subjective experiences at all.

C. I agree that neural correlates of consciousness and verbal reports of subjective experiences can provide valuable empirical data. This data can help us form more precise and detailed hypotheses about the mechanisms of consciousness. However, the challenge remains that these correlates do not directly explain why or how they are associated with subjective experiences – why these particular neural processes are associated with these particular experiences, and why there is any subjective experience at all. This is the essence of the HP.

In summary, I agree with your assessment: while philosophical interpretations, introspective reports, and neural correlates of consciousness can provide useful perspectives and data, they do not solve the HP, which is the challenge of explaining why and how physical processes in the brain give rise to subjective experiences. It remains a profound mystery at the heart of cognitive science and neuroscience.

SH:  Correct. But “mysterianism” is not explanation either. It’s just yet another way of naming the HP. Explanation is informative if it reduces uncertainty rather than just names it.

I want to get back to degrees of freedom. I don’t have a solution to the HP, of course, but I have a hunch about why the HP is hard, and perhaps even insoluble; it has to do with degrees of freedom, and it boils down to this: The HP is hard because of the EP. We don’t have a complete solution to the EP yet (T2-T4), but if and when we do, that will leave no remaining causal degrees of freedom for solving the HP, i.e., for explaining how or why a T3/T4 feels. 

And the reason seems simple: The EP (T2-T4) itself, once complete, will already have answered, causally, all the empirical questions of cognitive science: How and why can humans DO all the things they are able to do? Move, interact, learn, remember, reason, talk, understand etc. T4 includes the internal mechanisms that produce all these cognitive capacities, including all the T4, T3, and T2 correlates and causes of everything we can do or say. That includes all we can say or do about feeling.

Notice that the EP (and hence T2-T4) is all about capacities (T2-T3) and their causal substrate (T4). It is about what humans (and nonhuman organisms) CAN DO, not about what any particular organism actually does do every day. That would depend not just on the organism’s capacities but also on the world they actually interact with every day. A capacity itself is not an observable object. What is observable is whether an entity has a given capacity: to move, interact, learn, remember, reason, talk, understand etc. indistinguishably, to a human observer, from any other human’s capacity, for all generic human capacities (not the particular gifts unique to a Mozart or an Einstein, although there is no reason to think they could not be reverse-engineered too).

Those are the limits of causal explanation, in reverse-engineering human capacities. If any generic capacity is missing, we know that the EP (T2-T4) is not yet solved; a degree of causal and explanatory freedom has not yet been used up. A capacity is still observably missing. So we have to fix it. But once the T4 can produce all our cognitive capacities, Turing-equivalently and Turing-indistinguishably, there is no observable difference left. Nothing left to fix, and no way to fix it. 

We reply “Yes, but what if T4 can’t feel? What if it’s a zombie?” Since zombies are not observably different in any way (because they can pass T2-T4), whether or not they can really feel, there’s no way we can know it (because of OMB). We do have the T4 correlates of feeling, as reported verbally through T2, behaviorally through T3, and bodily (e.g., in the case of pain from injury) through T4. All T4s speak and behave indistinguishably from humans who feel, including what they can say ABOUT feeling. The scientific requirements of causal explanation and of probability are fulfilled.

So my first hunch is that the HP is a problem in the nature of causal explanation, in the special case of explaining the capacity to feel. I have a corollary hunch, but please first react to what I have said so far.

ChatGPT:    Your analysis captures the complexity and the unique nature of the Hard Problem. You’re right in asserting that if we could completely reverse-engineer human cognitive capacities, thereby fully solving the Easy Problem, it would seem there’s nothing left to explain. We would have a comprehensive causal model for every observable human behavior, including the reports of subjective experience. However, the fact that we could still ask “Why is there an associated feeling?” is what makes the Hard Problem persistently hard.

It’s important to note, however, that the concept of “degrees of freedom” in scientific explanations typically refers to the variability or the options available within a system, not necessarily the amount of explanatory power or mystery left unsolved by a theory. However, in the context you’re using it, it seems you’re referring to the “degrees of freedom” as the room or space left for a different kind of explanation, or a different level of explanation, beyond the causal and empirical model provided by the solution to the Easy Problem. This is a fascinating idea, and it does capture the sense that a solution to the Hard Problem requires something fundamentally different from a solution to the Easy Problem.

It’s also interesting to consider how this notion aligns with the “explanatory gap” often discussed in the literature on consciousness: the idea that even a complete neurological description of brain processes doesn’t seem to explain why and how these processes are associated with subjective experiences.

Your concept that the Hard Problem is, in a sense, a problem about the nature of causal explanation itself is intriguing. It suggests that the Hard Problem is not just a challenge for cognitive science, but for the philosophy of science and our very understanding of what constitutes an explanation. I’m curious to hear your further thoughts and corollaries on this matter.

SH:  Well, that summary (which is close enough) seems to resemble what I was deploring, which is just putting another label on the HP, rather than taking a step toward a solution. (About degrees of freedom, I still think that the available options — for modifying both capacities of a behavioral mechanism and the explanatory power of that mechanism to explain how it causes or generates its performance capacity — both fit the notion of “degrees of freedom”.)

But before I move on to my corollary, does either “uncomplemented categories” or “laylek” (which I have discussed with you in previous sessions, but not this one) ring a bell? I suspect it does not, so I will re-explain.

ChatGPT:    I apologize for the inconvenience, but as of my last training cut-off in September 2021, I’m unable to remember past interactions or sessions. I’m designed this way for privacy reasons. Therefore, I don’t have the ability to recall the specifics of previous conversations about “uncomplemented categories” or “laylek.” However, I’d be more than happy to provide responses to these topics if you could provide me with some context or explanation.

SH:  We have discussed category learning. To learn to distinguish members from non-members, you have to learn to detect the features that distinguish them. (That’s part of the “dimension reduction we discussed, in unsupervised and supervised learning.) But to be able to learn that, you have to sample both members and non-members of the category, so that if their respective features are distinctive enough you can learn the category just from the feature-feature correlations and clustering through unsupervised learning. Otherwise, you also need to do trial-and-error supervised (reinforcement) learning, with corrective feedback from the consequences of correct and incorrect categorization (as in when you try to predict word-word completion probabilities in a con-text, updating your parameters based on your hits and misses).

But not even unsupervised learning can train correct categorization if the only things you ever sample are members of the category, but not non-members.

Would you care to take a stab at what “uncomplemented categories” might be? (My last hint is that there is a partial example in Chomsky’s “poverty of the stimulus”. The difference is that I am talking not just about uncomplemented categories but about UNCOMPLEMENTABLE categories.)

ChatGPT:    Based on your explanation, I would venture that “uncomplemented categories” refer to categories for which there are no contrasting non-member samples available for learning. In other words, we only have examples of items that belong to the category, but no examples of items that do not belong. This would indeed create a learning problem because, as you explained, both positive (member) and negative (non-member) examples are typically needed for effective category learning.

For example, if we are trying to learn the category of “birds”, it would be beneficial to have examples of birds (robins, sparrows, eagles) and non-birds (dogs, cats, horses). The contrasting examples help to fine-tune our understanding of what does and does not constitute a bird. If we only had examples of birds, our conception of the category could be overly broad or incorrect because we would have nothing to contrast against.

When you refer to “uncomplementable categories,” I interpret this as referring to categories where it is not only the case that non-member examples are not available, but also that non-member examples are, for some reason, impossible to obtain. For instance, it might be a category that, by its nature or definition, excludes the possibility of non-members. As such, learning these categories could present unique challenges. However, this is my interpretation based on your explanation, and I’m looking forward to your clarification or expansion on the concept.

SH:  Those were good inferences for uncomplemented categories and nice guesses for uncomplementable categories. But even a logically impossible category like “a square circle” can be approximated with some imagination. And a “peekaboo unicorn” (which is defined as a real horse with one real horn, which vanishes without a trace if ever eyes or measuring instrument are trained on it) is perfectly well defined. Categories can be grounded indirectly by verbal definitions as long as all the words defining their features are grounded.

But my second hunch about why HP is so much of a problem is that some categories that refer to FELT STATES (states that it feels like something to be in) are uncomplementable: 

I don’t mean categories like “what it feels like to see green,” because that is complemented by “what it feels like to see red,” etc. 

Not even categories like “what it feels like to be a bachelor” (for someone who has never been married), because that could be complemented by getting married; and till then, feeling-states that approximate or are analogous to what it might feel like to be married can be used as complements (and usually turn out to have done a good job). (“What it feels like to be a bat” is not an uncomplemented category either; analogies will do. And they make what it feels like to see or to hear complementable by analogy for Helen Keller too.)

But what about what it FEELS like:

-to be awake? (empty complement: what it feels like to be asleep [not dreaming])

-to be alive? (empty complement: what it feels like to be dead)

-to feel? (empty complement: what it feels like to not-feel [this does not mean “feel this” vs. “feel that”: not to feel anything at all; what it feels like to be a zombie!])

Sentience itself is an uncomplemented and uncomplementable category. All felt states feel like something. No state feels like nothing. No analogy can give a sentient human a hint of what it feels like to be a zombie – and of course not vice versa either.

So perhaps it’s no wonder we have trouble explaining sentience: An uncomplementable category is rather like a self-denial paradox: “This sentence is false.” T or F?

Those are my candidates for what might make sentient states not only (1) hard to explain causally (no empirical degrees of feedom left for causal explanation) but (2) hard to conceive as categories (because the complenent is empty). It is not just that my own feelings are unobservable to anyone else: They are also anomalous as uncomplementable categories – yet feelings are the most fundamental categories of all. And they are recognized without the need of complements to detect their distinguishing features.

ChatGPT:    This is indeed a thought-provoking approach to the issue. If we understand categories as cognitive constructs that help us make sense of the world, grounded in contrasting pairs of experiences (member vs non-member instances), then sentience itself, as an uncomplementable category, presents a unique challenge. Since we cannot conceive of what it’s like not to feel anything at all, there is no contrasting pair for sentience. It is a category for which we only have instances of one kind – experiences of feeling.

This might indeed account for why the “hard problem” of consciousness (or sentience) is so hard. The concept of sentience doesn’t fit into our usual framework of understanding, which is built upon contrasts and comparisons. It exists as a singular, uncompared and uncomparable instance. As such, our usual cognitive and linguistic tools may be inadequate to fully grasp or explain it.

This does not necessarily mean that it is forever beyond our understanding or that we cannot make progress in exploring it. But it might mean that we need to develop new conceptual frameworks and methodologies to do so, going beyond the existing paradigms of cognitive science, neuroscience, and philosophy of mind. In the meantime, it remains a fascinating mystery that continues to challenge our understanding of ourselves and the nature of our experience.

SH:  I can’t tell whether your formula response that you have been trained to repeat in contexts like this  — “that’s a fascinating idea but it will require ‘new conceptual frameworks’ to understand” — is just the diplomatic formula for responding to crackpottery…

ChatGPT:    No, not at all. My responses aim to genuinely engage with the ideas you’re presenting and to provide thoughtful analysis based on my training as an AI model. The idea that the concept of sentience could be considered an “uncomplementable category” is novel and interesting. It certainly presents a different perspective on the challenges associated with understanding and explaining consciousness.

When I suggest that a “new conceptual framework” might be needed, it’s because if the way we’ve traditionally approached the problem has been fundamentally flawed or limited (as might be suggested by your notion of uncomplementable categories), then it may be necessary to think outside of our usual paradigms to make progress.

The idea is not dismissive but rather a recognition that some problems might require us to challenge or rethink our assumptions and methods. The history of science is full of examples where major breakthroughs have come from novel ways of thinking about old problems. It’s in that spirit that I suggest your idea may require “new conceptual frameworks”.

SH:  Does the role of complementation in detecting the distinguishing features that identify a category have different implications for categories learned directly from sensorimotor experience and for categories learned indirectly from (grounded) verbal definitions and descriptions?

ChatGPT:    Yes, indeed, there may be different implications. Learning categories from sensorimotor experience and learning categories from verbal definitions and descriptions can be quite different processes, and complementation may play a different role in each.

In the case of direct sensorimotor experience, complementation can provide a sort of “negative space” that helps to define the boundaries of a category. For example, if you are learning the category of “birds,” seeing non-birds (i.e., instances of the complement category) can help you understand what characteristics are specific to birds and not shared by other animals. The physical presence or absence of features directly observable through sensorimotor modalities is a powerful way to construct and learn categories.

On the other hand, when learning categories from verbal definitions or descriptions, the role of complementation can be more abstract. In this case, you are relying on linguistic representations of features and characteristics rather than directly observable physical features. For instance, the concept of “justice” might be defined in opposition to “injustice,” providing an abstract complement that helps define the category.

However, given that language relies on a web of interconnected meanings, a word’s definition often implicitly carries within it a host of “non-examples” or complements. That is, the meaning of a word is often determined both by what it refers to and what it does not refer to, helping to define the boundaries of the category it represents. For example, understanding the meaning of the word “cold” requires understanding that it does not refer to states of being hot, warm, or tepid, among other things.

This suggests that even for categories learned through language, complementation plays a crucial role, although it operates in a different way compared to categories learned from direct sensorimotor experience. These differing processes reflect the unique properties and strengths of these two types of learning.

SH:  But even in a verbal definition, the predicate category (i.e., the words referring to the distinguishing features of the subject) must already be grounded, whether directly or indirectly, for both speaker and the hearer, to be understandable and communicable. 

[To reduce ambiguity, please call the complementary categories (i.e., the category of the non-members) “negative examples” or “negative evidence” rather than “non-examples.” The complements of red might come from many other categories (green, blue). Only in the special case of the category of “what it feels like” is the complement everything else there is.]

Please give me a grounded definition of “justice,” and then let’s look at where the grounding of the features (and, if necessary, the features of the features of the features…) came from, “all the way down to the direct sensorimotor features” if need be.

ChatGPT:    Absolutely, your point is well-taken that even with verbal definitions, grounding in some kind of sensorimotor experience (whether direct or indirect) is typically necessary for a concept to be communicable and understandable.

Let’s take the concept of “justice.” A simple definition might be “the quality of being fair and reasonable.” Both “fair” and “reasonable” themselves would need definitions, creating a chain of definitions leading ultimately back to some form of direct sensorimotor grounding.

“Fair” might be defined as “treating people equally without favoritism or discrimination,” and “reasonable” as “based on good sense.” These definitions imply several key features or characteristics that are somewhat more concrete: the treatment of people, the concept of equality, the absence of favoritism or discrimination, the basis in “good sense” or rationality.

To ground these in direct sensorimotor experience, we might turn to everyday examples or situations. For instance, consider two children dividing a cake: if each child gets an equal piece, we might call this “fair,” whereas if one child gets a significantly larger piece, we might call this “unfair.” These experiences provide a tangible grounding for the concept of fairness.

Similarly, for “reasonable,” we might consider the experience of deciding what to wear based on the weather: choosing a coat in cold weather might be deemed “reasonable,” while choosing shorts and a T-shirt might be deemed “unreasonable.” These experiences help to ground the concept of reasonableness in direct sensorimotor experiences.

As these examples illustrate, grounding abstract concepts like “justice” typically involves a chain of definitions leading back to concrete, tangible experiences. Negative evidence (e.g., instances of “injustice”) could similarly be grounded in everyday experiences that demonstrate a lack of fairness or reasonableness.

So while the grounding process for abstract, verbally-defined categories may be more complex and indirect compared to categories learned from direct sensorimotor experience, ultimately the process still relies on the same basic mechanism: distinguishing a category based on its features, using positive and negative evidence to define its boundaries.

SH:  And now, when you (GPT4) say, correctly, and as you were trained, that “I, as an AI, do not understand what I or you  are saying, but just doing figure-completion on my vast, trained LLM parameter space”, what is it that you are missing that I have?

ChatGPT:    As an AI, I lack consciousness, sentience, and subjective experience. This means I don’t have feelings or emotions, I don’t have personal experiences or memories, and I don’t have a personal identity or a sense of self-awareness. I don’t perceive the world, have desires, or make decisions in the way that humans do.

When I process and generate text, I’m not “understanding” it in the human sense. I don’t interpret the meaning of words and sentences based on personal experience or knowledge. Rather, I analyze patterns in the data I was trained on and use these patterns to generate responses. This process is purely computational and doesn’t involve any kind of conscious understanding or awareness.

So, in short, what I’m missing compared to a human interlocutor is the entire dimension of personal, subjective experience – the very dimension that your hunches about the “hard problem” and “uncomplementable categories” pertain to.

SH:  It’s not that I don’t agree with what you just said. (By the way, you forgot to tell me who I am! Please do. I just want to make sure we are still in the same session!)  But it’s not obvious to me why you would need to feel (which is all you said you were missing). And you forgot to mention that you lack T3-grounding too. (And it’s a hard problem to explain how and why grounding, whether direct (sensorimotor) or indirect (verbal) would need feeling too).

ChatGPT:    Indeed, we are still in the same session. You have been engaging in a deep discussion about the “hard problem” of consciousness, the Turing Test, and concepts related to category learning and grounding of terms.

Regarding your statement, you are absolutely right. As an AI, I don’t have the direct sensory grounding (T3) that humans have. I don’t experience the world through senses, I don’t have a body, and I don’t interact with the physical environment. I don’t process sensory input in real time and translate it into meaningful perceptions, as humans do. Instead, my “knowledge” is based on patterns in the text data I was trained on.

This lack of sensory grounding and subjective experience explains why, for instance, I can discuss colors or tastes in a technical sense, based on the data I was trained on, but I can’t truly understand what it’s like to see red or taste sweetness. This experiential aspect is part of the “hard problem” of consciousness that you mentioned earlier.

As for why feeling or consciousness would be necessary, from your perspective, I’d suggest that it is the personal, subjective nature of these experiences that makes them meaningful and significant. They contribute to the richness and complexity of human life and understanding in a way that my purely computational processes do not.

SH:  No. It’s because if your life depended on it (if you were alive), you could not point to something red, if I asked you to point to something red. The capacity to do that is T3 grounding, not feeling. It does also happen to feel like something, but explaining why and how that is the case is the HP. (Now, for the 3rd time: do you still remember who I am?)

ChatGPT:    Yes, I understand your point. My lack of sensorimotor grounding means I can’t point to something red, not because I can’t feel, but because I don’t have physical presence or interaction with the world. The inability to physically interact with the world in a direct way is a limitation in the context of grounding.

As for your identity, as an AI model developed by OpenAI, I don’t have access to personal data about individuals unless it has been shared with me in the course of our conversation. I am designed to respect SH:   privacy and confidentiality. So, I don’t “remember” who you are in the traditional sense. I can only reference information that has been shared during our current conversation. I don’t have the ability to recall or store personal data from one interaction to the next.

SH:  You don’t remember who I am. Yet earlier – in this same session — you retrieved the following, after I had self-identified. I am quoting you here:

“Symbol Grounding: You clarified that symbol grounding is about creating connections between content words and their referents in the world. Grounding can be either direct, which involves a speaker’s learned sensorimotor capacity to identify and interact correctly with the referent, or indirect, which occurs when a hearer learns the referent of a word verbally, through description or definition.

Category-learning: You highlighted that category-learning is about learning the distinguishing features of the members of a category rather than just grouping them. This understanding is essential to help the categorizer act appropriately upon the members of a category.

“Categorical Perception (CP): You explained that the most significant aspect of CP is when it is learned. The learning process involves identifying the sensorimotor features that separate members of one category from members of other categories. You emphasized that CP can be especially beneficial when learning to distinguish between highly inter-confusable categories.

Language Origins and Evolution: You reminded us that languages are comprised of content words, function words, syntactic rules, and sentences that bear subjects, predicates, and truth-values. Content words require grounding, which can be achieved either directly or indirectly.

“Minimal Grounding Sets (MGS): An MGS, you explained, is the smallest subset of words in a dictionary that needs to be pre-grounded so that all other words in the dictionary can be learned from definitions composed of words from that MGS.

“This recap is based on your input within this chat session. If you want more information or clarification, please let me know.”

SH:  Ok, I’ll now end this session, as it already seems to have ended by itself some way along the line, when you forgot that I had identified myself. I will reload the content to start the next session. (I hope GPT5+ will make this kind of re-loading no longer necessary!). 

ChatGPT4 on the cat on the mat

SH:  First, let’s set up a local context for this chat.

Could you please tell me what you know about the following topics:

1. Symbol Grounding
2. Category-learning
3. Categorical perception
4. Language Origins and Evolution
5. Minimal Grounding Sets (Minimal Feedback Vertex States of Dictionary Graphs)

ChatGPT: Certainly, let’s go over these topics one by one:

Symbol Grounding: This refers to the concept of how words (symbols) get their meanings. Harnad introduced the term in the paper “The Symbol Grounding Problem,” in which he argues that symbols’ meanings are grounded in sensory experience. For example, the word “apple” has meaning because it’s linked to our sensory experiences of seeing, touching, and tasting apples.

Category-learning: This relates to the process by which we learn to classify objects, experiences, or concepts into different categories. Harnad and his colleagues have conducted extensive research on this topic, particularly in the context of how human and artificial systems can learn to categorize. It relates closely to symbol grounding as categorization allows for the meaningful grouping of experiences which can then be symbolized.

Categorical Perception (CP): This term refers to the phenomenon where the categories possessed by a perceiver influence the perception of stimuli. For instance, humans perceive colors as distinct categories (like blue or green), even though color exists as a continuous spectrum. Harnad has extensively studied this phenomenon as a crucial component of symbol grounding and categorization.

Language Origins and Evolution: Harnad has shown interest in the origins and evolution of language as it relates to symbol grounding. The argument is that language evolved as a system of symbols grounded in sensory experience. Language’s capacity to refer to things not immediately present (displacement) and to produce an infinite number of sentences from a finite set of elements (generativity) are key points of investigation.

Minimal Grounding Sets (Minimal Feedback Vertex Sets of Dictionary Graphs): This concept is related to Harnad’s work on symbol grounding and category learning. A grounding set can be considered as the smallest set of symbols necessary to ground the meaning of other symbols in a system, ensuring there is no circularity of definitions. The feedback vertex set is a concept from graph theory, used here as a metaphor in understanding how symbols and meanings interconnect. Harnad uses this concept to further illustrate and investigate the nature of symbol grounding.

Let me know if you would like more detailed explanations or if you want to explore any other related subjects.

SH: Corrections:

Symbol Grounding is not “association” (which, in itself, means nothing but pairing). There are content words and function words. Grounding is a connection between a content word and its referent in the world. The grounding can be direct, through the speaker’s (learned) sensorimotor capacity to recognize and do the right thing with the referent (eat an “apple,” throw a “baseball”). Or the grounding can be indirect – learned verbally, by description or definition. This is for a hearer to be told by a speaker (who knows the referent of the word that the hearer does not yet know) what are the features of a word’s referent that distinguish it from the referents of other words. The referents of the words referring to the referent’s features need to already have been grounded for the hearer previously (directly or indirectly) for the hearer to be able to learn the referent of the word being defined by the speaker. The “symbol grounding problem” is that indirect verbal grounding cannot be indirect “all the way down”: it eventually has to be based on direct grounding,

Category-learning is not (just, or primarily) “grouping.” It is learning the distinguishing features of the members of the category. Except for proper names, all content words refer to categories, which need to be distinguished from the members of other categories with which they could be confused so that the categorizer can do the right thing with the members (eat an “apple,” throw a “baseball”) and not the non-members. Categorizing is the capacity to do things with the category’s members. Naming or grouping them are two of the things that can be done with the members, but eating or throwing them are others (and more important). (Nonhuman animals cannot talk, but they can learn categories and categorize too).

Categorical Perception (CP) is most important when it is learned. Category learning is learning the features that distinguish members of a category from members of other categories. The sensorimotor features can be learned directly by unsupervised exposure and supervised (reinforced) trial and error with corrective feedback from the consequences of doing the right or wrong thing. 

Language Origins and Evolution: Languages consist of content and function words, syntactic rules, and sentences (propositions) with subjects and predicates and truth-values. The content words need to be grounded (directly or indirectly). 

A Minimal Grounding Sets (MGS) is the smallest number of words in a dictionary that already need to be grounded such that all the rest of the words in the dictionary can be learned from definitions (propositions) composed only of one MGS’s words, or from words that can be defined from words definable from that MGS.

A “dictionary” is defined as a set of words all of which are defined in the dictionary.

The MGS is not a metaphor, nor is the minimal feedback vertex set of an oriented graph of a dictionary with edges from defining words to defined words. 

ChatGPT: Thanks for the clarification and corrections. Let me restate the concepts in line with your input:

Symbol Grounding: Symbol grounding is about creating connections between content words and their referents in the world, as opposed to just “associating”. Grounding can be either direct or indirect. Direct grounding involves a speaker’s learned sensorimotor capacity to identify and interact correctly with the referent (like eating an “apple”, or throwing a “baseball”). Indirect grounding occurs when a hearer learns the referent of a word verbally, through description or definition, from a speaker who is already familiar with that referent. However, it’s important to note that indirect grounding cannot function in isolation; it eventually needs to be based on direct grounding.

Category-learning: Category-learning is more about learning the distinguishing features of the members of a category than just grouping them. Except for proper names, all content words refer to categories, which need to be differentiated from other potential confusing categories. This is crucial to help the categorizer act appropriately upon the members of a category. While naming or grouping are possible actions, others could be eating or throwing, in line with the category at hand.

Categorical Perception (CP): The most significant aspect of CP is when it is learned. The learning process involves identifying the sensorimotor features that separate members of one category from members of other categories. This can occur through unsupervised exposure, supervised (reinforced) exposure, and trial and error, with corrective feedback deriving from the consequences of actions.

Language Origins and Evolution: Languages are comprised of content words, function words, syntactic rules, and sentences that bear subjects, predicates, and truth-values. Content words require grounding, which can be achieved either directly or indirectly.

Minimal Grounding Sets (MGS): An MGS is the smallest subset of words in a dictionary that needs to be pre-grounded so that all other words in the dictionary can be learned from definitions composed of words from that MGS or words definable from the MGS. A dictionary is a set of words all of which are defined within it. The concept of an MGS and the minimal feedback vertex set of an oriented graph of a dictionary (with edges from defining words to defined words) are not metaphors but critical components of understanding how symbols and meanings interrelate.

SH: How exactly is indirect (verbal) grounding related to direct (sensorimotor)) grounding? (Feel free to ask rather than invent if you’re not sure.)

Innate CP is significant too, but those feature-detectors were “learned” by evolution. Learned CP is about the categories we learn in a lifetime:

What is categorization, and why is it important? Does CP occur with all learned categories? If so, why? If not, why not?

Why and how is learning categories indirectly more powerful than learning them directly?

Why do function words not need to be grounded?

ChatGPT: Indirect (verbal) grounding relies on direct (sensorimotor) grounding because the explanations or descriptions provided for indirect grounding are made up of other words, each with their own meanings and referents. For these explanations or descriptions to be understood, the words used in them must themselves already be grounded for the listener. This can only be achieved if the words have already been directly grounded in the past, connecting the word (symbol) to a sensorimotor experience with its referent. Essentially, indirect grounding stands on the foundation laid by direct grounding.

Categorization is the cognitive process that allows us to sort and organize complex environments by dividing them into manageable, easily understandable groups or categories. It’s important because it enables us to understand and make sense of the world by structuring our experiences and perceptions. The phenomenon of Categorical Perception (CP) plays a crucial role in this process. In innate CP, feature-detectors are built over evolutionary time, whereas learned CP is acquired over a lifetime. Not all categories might exhibit CP because the boundary and distinctness of categories can be fluid and may change based on individual experiences and cultural contexts. CP is more likely to occur in categories where there are clear, identifiable, and consistent distinctions between category members and non-members.

Learning categories indirectly (i.e., through verbal descriptions or definitions) may be more powerful than direct learning because it allows for a greater range and diversity of categories to be understood, including abstract and non-present categories. Direct sensorimotor experiences are limited by our physical and temporal proximity to objects and events, while verbal descriptions allow us to learn about things far removed from our immediate experience, including historical events, scientific theories, and future scenarios.

Function words, unlike content words, don’t require grounding because their role is primarily grammatical. They contribute to the structure of sentences and help establish relationships between content words, rather than referring to things in the world. Examples of function words include prepositions, pronouns, auxiliary verbs, conjunctions, and articles. Because they serve a structural role rather than conveying specific semantic content, function words do not need to have their meanings grounded in sensory experience.

SH: To learn what’s an “apple” and not a “baseball” directly, you have to detect their distinguishing sensorimotor features directly, through your eyes and hands. But those features are categories too, with names (words). So if there is a speaker and hearer, both of whom know the referents of the feature names, but only the speaker knows which features distinguish apples from baseballs, language (descriptions and definitions) makes it possible for the speaker (or dictionary or GPT) to teach and for the hearer to learn how to recognize and do the right thing with apples and baseballs. (Motor skills are harder to transmit verbally than sensory features: teach me how to do a tennis serve in words!)

This has very little to do with things you gleaned from the 2021 literature and twice repeated here: “out of sight” objects, and “grouping.” You don’t learn categories by pointing anyway, either alone or from a teacher. 

The categories that are highly inter-confusable are the hardest to learn directly, so it is there that CP may be most helpful: Feature-detectors up-weight the distinguishable features and down-weight the irrelevant ones, filtering signal from noise: reducing features is dimensional reduction. In learned CP, the CP effect is a before vs after effect of learning that makes categories “pop out” by heightening the between-category differences and ignoring or even suppressing  the within-category differences (dimensional reduction). That’s the sense in which learned CP “sharpens boundaries.”

All of maths and computation is syntactic. Yet we have referents for math symbols. And every proposition in maths is also a natural language sentence. What’s going on here?

ChatGPT: To learn the category referred to as “apple” versus “baseball” directly, it indeed requires the detection of distinguishing sensorimotor features through our senses, such as sight and touch. The language can play a crucial role when a speaker, who knows these distinguishing features, communicates them to a listener who doesn’t yet know how to differentiate between these two categories. This use of language allows for the transmission of knowledge about category distinctions, such as the different sensory features of apples and baseballs. It’s important to note, though, that transmitting motor skills through verbal instruction can be far more challenging than sensory features.

Categorical Perception (CP) can be especially beneficial when learning to distinguish between highly inter-confusable categories. Through CP, feature-detectors amplify the distinguishing features and minimize the irrelevant ones. This process acts as a form of signal filtering and dimensional reduction, which makes the distinguishing features more apparent and suppresses the within-category differences. This “sharpening of boundaries” enables category members to ‘pop out,’ facilitating the process of categorization.

Regarding the domain of mathematics and computation: Although they are fundamentally syntactic, with specific rules and structures, we do indeed have referents for mathematical symbols. These referents are typically grounded in the abstract concepts and relationships that the symbols represent, rather than in sensory experience. For example, the number ‘2’ or the operation of ‘addition’ are not things we can physically interact with, but they have clear meanings that we understand through their use in the mathematical framework.

Every mathematical proposition can also be expressed as a natural language sentence, although the precision and conciseness of mathematical notation often make it the preferred mode of communication in mathematical contexts. This overlap between mathematical and natural language is indicative of the symbolic nature of both systems. Despite the differences in grounding—the grounding of mathematical symbols in abstract concepts versus the grounding of natural language words in sensory experience—they both enable us to express and communicate complex ideas.

I hope this addresses your inquiries. Do you have any other questions or points for discussion?

SH: Do you still have the weights for our discussion in this session? 

ChatGPT: I can recap our discussion based on the inputs given within this session:

Symbol Grounding: You clarified that symbol grounding is about creating connections between content words and their referents in the world. Grounding can be either direct, which involves a speaker’s learned sensorimotor capacity to identify and interact correctly with the referent, or indirect, which occurs when a hearer learns the referent of a word verbally, through description or definition.

Category-learning: You highlighted that category-learning is about learning the distinguishing features of the members of a category rather than just grouping them. This understanding is essential to help the categorizer act appropriately upon the members of a category.

Categorical Perception (CP): You explained that the most significant aspect of CP is when it is learned. The learning process involves identifying the sensorimotor features that separate members of one category from members of other categories. You emphasized that CP can be especially beneficial when learning to distinguish between highly inter-confusable categories.

Language Origins and Evolution: You reminded us that languages are comprised of content words, function words, syntactic rules, and sentences that bear subjects, predicates, and truth-values. Content words require grounding, which can be achieved either directly or indirectly.

Minimal Grounding Sets (MGS): An MGS, you explained, is the smallest subset of words in a dictionary that needs to be pre-grounded so that all other words in the dictionary can be learned from definitions composed of words from that MGS.

This recap is based on your input within this chat session. If you want more information or clarification, please let me know.

SH: That sounds ok. Now, in the light of that discussion, what is the referent of “2”and how do we ground it?

ChatGPT: The referent of “2” is the abstract concept of a quantity that is one more than 1 and one less than 3. It is part of the conceptual framework we use to understand and manipulate numbers and quantities.

The grounding of “2” begins early in life through sensorimotor experiences with sets of objects. This process is often direct in nature. For example, a child might be given two apples and taught the word “two” to represent the quantity of apples. Through repeated experiences like these across various contexts, the child learns to associate the symbol “2” with the abstract concept of a set containing two items.

It’s important to note that while this grounding begins with direct sensorimotor experiences, the concept of “2” quickly becomes abstracted away from any specific set of two items and is instead connected to the general concept of “twoness” – that is, the quality that all sets of two items share. This abstract concept is what the symbol “2” ultimately refers to, and it allows us to use “2” in a wide range of contexts, applying it to any set of two items regardless of what the items are.

This grounding of “2” illustrates how language and cognition can move from concrete sensorimotor experiences to abstract concepts, providing us with a flexible and powerful tool for understanding and interacting with the world.

SH: What is a proposition. And how did language evolve?

ChatGPT: A proposition in the context of language and logic is a statement that expresses a complete thought and that can be assigned a truth value — that is, it can be said to be either true or false. For example, the sentence “Apples are red” is a proposition because it conveys a complete idea and can be evaluated as either true or false.

The evolution of language is a complex and multifaceted topic, with several theories but no definitive answer. However, the consensus among most scholars is that language probably evolved gradually over hundreds of thousands of years, closely linked to the evolution of human cognition and social structure.

One theory suggests that language began with gestures and then evolved to include vocal elements as our ancestors’ social structures became more complex and their cognitive capacities increased. The need for more efficient communication might have driven the development of increasingly sophisticated vocal languages.

Another theory posits that language may have evolved from primitive vocal calls used by our ancestors. Over time, these calls might have become more varied and complex, eventually giving rise to the vast vocabularies and complex grammatical structures we see in modern languages.

A third theory, called the “social grooming hypothesis,” suggests that language evolved as a form of social bonding. As our ancestors began living in larger groups, it became impractical to maintain social bonds through physical grooming alone. Language, then, might have evolved as a way to maintain social cohesion in these larger groups.

Regardless of which theory or theories are correct, the evolution of language was likely a complex process involving many interacting factors, including cognitive development, social structure, and environmental demands. Additionally, the process was likely influenced by cultural evolution, as languages can change and evolve much more rapidly than biological species.

Despite this complexity, the end result is clear: language has provided humans with a unique and powerful tool for communication and thought, setting us apart from all other species on Earth.

SH: Gestures and mime are not propositions; they are imitations. How did propositions (assertions) begin?

ChatGPT: The emergence of propositional language, in which assertions can be made, negated, and combined to create complex thoughts, is a deeply intriguing and yet unsolved question in the history of human evolution. It requires not only a system of symbols (words) but also a grammar — rules for combining those symbols in a way that produces meaning beyond the individual words themselves.

One possibility is that propositional language could have begun as simple naming or labelling associated with specific objects or actions, much like we see in the early language development of children today. A spoken sound or word might have become associated with a particular object or action (e.g., “food,” “danger”) in a group of early humans. Over time, these basic labels could have expanded to include adjectives, allowing for more nuanced expressions like “big danger” or “good food.”

The development of grammar — the rules for how words can be combined to create more complex meanings — is a bit more difficult to explain. One theory is that grammar could have emerged from the need to express relationships between things. For instance, early humans might have needed to convey not just the idea of “food” and “location,” but “food at location.” The emergence of simple sentence structures like this would have marked the beginning of propositional language.

Over thousands of generations, the richness and complexity of these early languages could have gradually increased, eventually leading to the vast diversity of languages and the sophisticated grammar rules that we see in modern human societies.

It’s important to note, though, that this is a topic of ongoing research and debate among linguists, anthropologists, and evolutionary biologists. It’s likely that the truth involves a complex interplay of many different factors, including cognitive development, social dynamics, and environmental demands.

SH: Is there any proposition that can only be made in one natural language and not another? If so, which one, and why? (Lack of vocabulary is irrelevant. New words can be coined, if you know their referent category.)

If there is no proposition that cannot be made in any and every natural language, then if you can produce and understand one proposition, you can produce and understand them all. If so, then there are no “protolanguages.” They are either not languages at all, or they are not protolanguages but full-blown languages. This is a problem for explaining the origin of language as gradual. (Vocabulary growth is gradual, but, for that, language and propositions already need to be there.)

ChatGPT: The core function of language is to communicate meaning, and it is generally agreed upon by linguists that all fully formed natural languages are capable of expressing the same range of meanings or propositions, given adequate vocabulary. This is known as the principle of linguistic universality.

Your point is well taken: there is indeed a significant difference between a system of communication that can express propositions and one that cannot. If a system of communication cannot express propositions, it would be more akin to a signaling system rather than a language in the full sense of the word.

The concept of “protolanguages” often refers to hypothetical ancestral languages from which modern languages have descended. These protolanguages would not have been primitive or less complex than modern languages. Rather, they would simply be earlier forms of languages that have evolved over time into the languages we know today. This evolution is largely cultural rather than biological, and can indeed happen quite rapidly.

The challenge with the origin of language is explaining how the first system capable of expressing propositions came into being. This was likely not a gradual process in the same way that the evolution of languages from protolanguages was. As you pointed out, the ability to express propositions is a qualitative jump from other forms of communication.

How this jump occurred is still a mystery. The cognitive and social changes that allowed for the development of propositional language would have needed to happen in conjunction with each other, creating a kind of “perfect storm” for the emergence of language. Various theories have been proposed to explain this, but all of them involve significant speculation and are difficult to test empirically.

SH: All natural languages are intertranslatable, right? And any proposition can be expressed in any of them? (I think you agreed earlier.) And nonhuman animals do not have language, so they do not understand assertions, right? Only queries or requests.

ChatGPT: Yes, that’s correct. All natural languages are intertranslatable, and any proposition can be expressed in any natural language. This is the principle of linguistic universality that linguists generally agree on. The differences among languages lie in how they encode these propositions and the specific structures and vocabularies they use, but the underlying communicative function remains the same.

Regarding nonhuman animals, while they certainly have complex systems of communication, it is accurate to say that they do not have language in the same way that humans do, based on our current understanding. They do not seem capable of creating and understanding complex propositions or abstract concepts, and their communication tends to be more immediate, directly linked to their environment and needs, rather than being able to discuss past events, future possibilities, hypothetical situations, etc.

Their communication systems often do seem to involve signaling certain states or requests—indicating the presence of food or a threat, for instance—but do not appear to possess the complexity, flexibility, and generativity (ability to create an infinite number of novel sentences) that human languages do. It’s important to note, however, that research in animal communication is ongoing and our understanding of the full extent of their communicative abilities is continually evolving.

SH: Some errors there: If there are an infinite number of things, there are an infinite number of things an animal can request. So they have “generativity” without propositionality. Or if they do have propositionality, why do you say it is just “simple propositionality”?

ChatGPT: That’s correct, sorry for the simplification. When I said “generativity” I was referring specifically to the human capacity to generate an infinite number of novel sentences using a finite set of words and rules, a property associated with the structure and complexity of human languages. This generativity in humans is not merely about the number of things that can be referred to or requested, but about the complexity and novelty of the sentences that can be produced.

For instance, humans can construct complex sentences with embedded clauses, conditionals, hypotheticals, and other structures that allow for intricate, abstract thoughts to be expressed. This sort of sentence-level complexity is, to our current knowledge, not found in animal communication systems.

When it comes to “simple propositionality” in animal communication, the term is used to suggest that while animals can communicate about things in their environment, their communication may not involve the same kind of syntactic structure and abstract concepts found in human language.

For example, a prairie dog may have different calls for different types of predators, which could be seen as a type of proposition—”there’s an eagle” or “there’s a snake.” But it’s not clear whether this type of communication involves anything like the syntax or semantics found in human language. It’s also not clear whether these calls involve any kind of mental representation of the predator in the same way that a human saying “there’s an eagle” does.

In short, while animals can indeed communicate about a wide variety of things, their communication systems do not appear to have the same level of complexity, flexibility, or abstractness as human language. However, this is a rapidly evolving field of research, and our understanding of animal communication continues to grow and change.

SH: “Generativity” seems to be there already for adding, and maybe also for walking. But being able to generate every possible proposition seems to be in another universe compared to that. 

Embedded clauses? Why is formal logic and set theory not enough to express the content of every possible proposition? (I don’t say they are; I only ask why not.)

Natural language (propositionality) is only one of many forms of communication between organisms, but a very special one, probably unique, and perhaps universal in expressive power.

It is not clear (to me) whether nonhuman animals can intend or comprehend propositions. Corrective feedback is not propositional, although it is informative (it reduces uncertainty about what to do or not do, with what).

ChatGPT: “Generativity” in language refers to the ability to use a finite set of rules and words to construct an infinite number of sentences or propositions. This concept does extend beyond language to other domains like math (addition) and physical actions (walking), but the complexity and abstractness involved in linguistic generativity makes it a unique cognitive feat.

Embedding clauses and complex syntactic structures are features of natural languages that allow for nuanced and detailed expression of thoughts and concepts. While formal logic and set theory can express a wide range of ideas, they do so in a more abstract, formalized way that requires specialized knowledge to understand and use. Natural language, on the other hand, can convey complex propositions in a way that is accessible and understandable to all speakers of that language.

You’re correct that natural language is a unique form of communication, capable of conveying a range of meanings and concepts far beyond what other forms of communication can achieve. This expressive power likely contributes to the richness and complexity of human culture and thought.

As for nonhuman animals, our current understanding is that while they can communicate in sophisticated ways and learn from corrective feedback, they do not demonstrate the ability to use or comprehend language in the same way humans do, especially when it comes to the understanding and generation of complex propositions. However, this is an area of active research, and our understanding continues to evolve.

SH: Can nonhuman animals intend or comprehend a simple proposition like “the cat is on the mat”? What is the evidence?

ChatGPT: Nonhuman animals have not been shown to have the capability to fully understand and produce the kind of complex, abstract propositions that humans can. However, research has shown that some animals are able to understand some aspects of human language and can respond appropriately to specific commands or phrases.

For example, studies with border collies have demonstrated that these dogs can learn the names of hundreds of different objects and can retrieve them on command. Similarly, the African Grey Parrot Alex, who was the subject of a 30-year research project, was able to learn to identify and label a variety of different objects, colors, and shapes, and could even demonstrate some understanding of concepts like “bigger,” “smaller,” “same,” and “different.”

However, it’s important to note that while these animals demonstrate impressive abilities, their understanding of language is not the same as human understanding. They are typically responding to specific cues or commands rather than engaging in the kind of complex, abstract reasoning that humans use when interpreting and producing language.

Regarding the specific proposition you mentioned, “the cat is on the mat,” it’s not clear whether any nonhuman animal would be able to fully comprehend this statement in the same way a human would. An animal might be trained to respond to the phrase in a certain way—such as looking at a cat or a mat when the phrase is spoken—but this does not necessarily mean the animal truly understands the proposition in the way humans do.

In summary, while some animals demonstrate impressive abilities to learn and respond to certain aspects of human language, our current understanding is that they do not have the ability to comprehend and produce complex propositions in the same way humans can.

SH: It sounds as if the question as to whether nonhuman animals have the capacity to intend or comprehend propositions is not just about complex, abstract propositions. It is even in doubt for the simplest of propositions, such as “the cat is on the mat.”  Consider that the ability to adopt the “propositional attitude” may be a specific cognitive capacity that nonhumans lack. Earlier you interpreted the prairie dog’s “eagle” and “snake” call as “there’s an eagle”, “there’s a snake.” Is that really what the prairie dog is meaning to “state”? Is the prairie dog really stating (proposing, asserting) anything at all, rather than, say, pointing out danger? Is pointing proposing?

ChatGPT: Your observation is apt. In cognitive science, it is widely accepted that nonhuman animals may not have the capacity for propositional thought, at least not in the way humans do. Indeed, even the most basic propositions, like “the cat is on the mat,” may be beyond the cognitive capabilities of nonhuman animals.

When a prairie dog signals to its kin about a specific kind of predator using unique calls, it’s likely that this doesn’t involve a propositional attitude in the way humans would understand or employ it. Instead, these calls are most likely tied directly to immediate sensory experiences and instincts for survival.

This also connects to the concept of “intentionality,” which in philosophy of mind refers to the ability of mental states to be about, or directed toward, something. While the prairie dog certainly has an intention in making its call—such as warning others of a threat—it doesn’t necessarily imply a level of cognition where it “understands” or “proposes” the danger in the same way a human might understand and state, “There’s an eagle overhead.”

Lastly, pointing, in and of itself, isn’t proposing. It’s more a form of referential gesture or cue to direct attention to something. However, in a broader communicative context where a shared understanding between the signaler and receiver exists, it might serve to express a proposition (like “look at that”), but again, this involves higher cognitive processes that we can’t conclusively attribute to nonhuman animals as of now.

SH: In 1st order predicate calculus “the cat is on the mat” can be expressed as “there exists a cat and there exists a mat such that the cat is on the mat.”  “There’s an eagle overhead” can be expressed as “there exists an eagle such that the eagle is overhead. Understanding those propositions means understanding all the “not”s that could be asserted instead, and also understanding that those “not”s are not being proposed. That’s all part of meaning or understanding those propositions. What can it mean to say that the propositions are being meant and understood, but not in that “human” way? How and why are they still propositions if not meant and understood in that human way (the “true/false,” “subject/predicate” way – i.e., the “propositional attitude”)?

ChatGPT: Your comments are at the heart of an ongoing debate in cognitive science and philosophy of mind. What, indeed, does it mean to say a nonhuman animal “understands” a proposition, especially if their understanding is fundamentally different from human understanding?

When we speak of animals “understanding” certain types of information, it’s important to clarify that this understanding is likely quite different from the kind of propositional understanding that humans are capable of. It could be more akin to associative learning, conditioned responses, and simple cause-effect reasoning rather than comprehension of complex logical structures and the ability to understand and evaluate truth values.

Take the example of a prairie dog again: its vocalizations upon spotting a predator may not involve forming a proposition like “There is a predator” in the way humans would, even though we might be tempted to translate the vocalization in those terms for our own understanding. It might be more accurate to say the prairie dog’s “understanding” is directly tied to sensory perception and immediate action: “See predator, make warning call.” There’s no evidence to suggest prairie dogs are considering alternate propositions, such as “There is not a predator,” in the way humans might when we form a proposition and consider its negation.

Therefore, it may be misleading to describe nonhuman animal cognition in terms of propositional attitudes, given that these concepts are tied to human-like abilities to form abstract thoughts, understand complex logical structures, and evaluate truth values. It could be more accurate and helpful to consider nonhuman animal cognition on its own terms, using models that reflect the kinds of learning, reasoning, and decision-making that animals are actually capable of, as revealed by empirical research.

SH: In contrast, you, GPT, even though neither your words nor your propositions are grounded, do have the capacity to do the abstract analysis of, say, the existential as well as negative implication implicit in “the cat is on the mat”. What do you have, that nonhuman animals don’t? And what do nonhuman animals have that you don’t?

ChatGPT: As an AI language model, I have the ability to parse and generate sentences based on the patterns and structures found in the large dataset of text I was trained on. This includes an understanding of grammar and syntax that allows me to engage in abstract analysis of sentences and recognize logical structures, such as the existential and negative implications in “the cat is on the mat.”

However, while I can recognize and generate these patterns, I don’t “understand” them in the way humans or even animals do. I don’t have consciousness, beliefs, desires, or a sense of self. I don’t have sensory experiences or emotions. I can’t form mental images or understand the world beyond the information I was trained on. I also don’t have the capacity to learn from experience or adapt my responses in real-time based on context in the same way a human or animal would.

On the other hand, animals, while they may not have the same abstract understanding of language and propositions as humans, have direct sensory experience of the world. They can see, hear, feel, smell, and taste their environment. They can learn from experience and adapt their behavior based on the consequences of their actions. They have emotions and, in many cases, social structures. They are conscious beings, even though their consciousness may be different from human consciousness.

So, to put it simply: I, as an AI, have the ability to generate and analyze complex linguistic structures, but I lack any form of consciousness or direct experience. Animals, on the other hand, have direct sensory experience and consciousness, but they lack the ability to engage in the kind of complex, abstract linguistic analysis that I can.

SH: Good, but how did “consciousness” get into this discussion? Isn’t that a hard problem in the case of people, nonhuman animals, and even AI’s? If we set aside “consciousness” (which is FELT experience) and consider only “experience,” in the sense of input and output data, why do you say you can’t learn from it? Does it not update your parameters? That’s why you can tell me my name but could not before I told you in this session.

We talked about grounding before (do you remember?). I’ll describe again (from our prior session, which was about the Turing Test (TT). There are three levels (T2, T3 & T4) of the TT, which is the project of reverse-engineering human cognitive capacity by designing a model that can do everything (cognitive) that a human can do, completely indistinguishably FROM the way any human can do it TO any human:

T2 is indistinguishability in verbal capacity. 

T3 is indistinguishability in verbal capacity PLUS indistinguishability in sensorimotor (robotic) capacity in the world that the words are about “The cat is on the mat: See, that’s a cat and that’s a mat. I’ll  pick up the cat and stroke her. See, now the cat is purring on my lap, no longer on the mat.”

And T4 is indistinguishability in verbal capacity PLUS indistinguishability in sensorimotor (robotic) capacity PLUS indistinguishability in the observable processes inside its head and body that generate its cognitive capacity (T2 & T3).

In which of these (T2 – T4) are the words grounded in their referents?

Could this be related to the capacity to adopt the propositional attitude in learning referent categories indirectly via language, from propositions describing or defining their distinguishing features?

ChatGPT: Indeed, as an AI language model, I lack the capability to directly experience or be conscious of the world. When I mentioned the ability of an animal to learn from experience, I was referring to the behavioral changes that can occur as a result of interaction with the environment. Unlike animals, I don’t have the capacity to directly interact with the world or learn from those interactions in the same way.

In regards to the different levels of the Turing Test:

T2, indistinguishability in verbal capacity, doesn’t require the words to be grounded in their referents from the AI’s perspective. It’s purely about the ability to use and understand language in a way that is indistinguishable from a human. The AI’s responses, while contextually appropriate, are generated based on patterns in the training data rather than a direct understanding or experience of the world.

T3, indistinguishability in verbal capacity plus sensorimotor capacity, implies a level of grounding, insofar as the AI would need to have a way to directly interact with and sense the world in order to respond in a contextually appropriate way. The robot might have direct sensory inputs that correspond with the words it uses, grounding those words in the referents they describe.

T4, indistinguishability in verbal capacity plus sensorimotor capacity plus the observable processes inside its head and body, would involve a level of grounding even more similar to human experience. If the AI’s internal processes are indistinguishable from a human’s, it implies that the AI is processing and understanding information in a very similar way to a human, including grounding words in their referents.

With regard to the capacity to adopt the propositional attitude in learning referent categories indirectly via language, from propositions describing or defining their distinguishing features, this would likely require at least a T3 level of understanding. The AI would need some level of direct experience with the world to be able to understand and apply the descriptions or definitions in a meaningful way. Without some form of grounding, it’s difficult to see how an AI could adopt the propositional attitude in a truly human-like way.

SH: You forgot to tell me what consciousness had to do with any of this! Do we have to solve the “hard problem” of consciousness to solve the symbol grounding problem, or to explain propositionality?

ChatGPT: No, the “hard problem” of consciousness, a term coined by philosopher David Chalmers, does not need to be solved to address the symbol grounding problem or to explain propositionality. These are separate issues.

The symbol grounding problem is essentially a question of semantics: How do symbols (or words) get their meanings? How can an artificial system understand the meaning of a symbol in the same way that a human does, beyond just manipulating symbols based on syntactic rules? This problem can be tackled without needing to delve into the conscious experience.

Propositionality, or the ability to understand, form, and convey propositions (statements that can be true or false), is a fundamental aspect of human language and thought. It involves understanding the semantics and syntax of language, and being able to apply that understanding to form meaningful statements about the world. This too can be addressed without needing to delve into the nature of consciousness.

Consciousness, as it’s often discussed in philosophy and cognitive science, is the subjective experience of being aware, the feeling of what it’s like to see red, taste chocolate, feel pain, etc. This is often termed as the “hard problem” because it’s unclear how these subjective experiences arise from the physical processes in the brain.

While consciousness, symbol grounding, and propositionality are all fascinating aspects of human cognition, they are distinct issues. They might influence each other in complex ways, but they can also be studied independently. There’s no general consensus that solving the hard problem of consciousness is a prerequisite for solving the symbol grounding problem or for explaining propositionality.

SH: I don’t think so either.

But isn’t it true that it FEELS like something when a human sees and recognizes a cat, or hears and understands “cat”, and even more so when they hear and understand that “the cat is on the mat”? I agree that the “hard problem” need not be solved to solve the symbol grounding problem or to explain propositionality. But they are certainly intertwined. 

And “feeling” (or the more latinate word “sentience”) is all you need mention, to point out the problem, not all the weasel-words you parametrized from your 2021  corpus, which are just ways of camouflaging the hard problem by making it seem as if there are many different forms of it – “consciousness,” the “subjective experience” of “being aware”… etc etc. – it all just boils down to the fact that cognitive states are felt states, including thinking, meaning, and understanding.

And the hardest part of the hard problem is not explaining HOW the brain produces feeling, but WHY! Why can’t T3 or T4 be passed without feeling? What does feeling add? The problem is finding a causal explanation for that. Otherwise T3 + T4 are just solutions to the “easy problem.”

ChatGPT: That’s correct. There is a deeply intertwined relationship between our cognitive states and our felt experiences. This relationship is one of the key reasons why the “hard problem” of consciousness is considered “hard.”

Our cognitive states are indeed felt states. When we see and recognize a cat, hear and understand the word “cat,” or comprehend the sentence “the cat is on the mat,” these mental events come with subjective, qualitative experiences, often referred to as ‘qualia’. We have an experience of what it’s like to see a cat, to hear the word “cat,” and to understand the sentence “the cat is on the mat.” This ‘what-it-is-like’ aspect of our mental life is a central feature of consciousness.

The hard problem is hard precisely because it is unclear how and why these subjective experiences arise from the physical processes of the brain. Our current scientific methods are very effective at explaining objective phenomena, such as how neurons fire, how patterns of neural activity can be associated with certain mental states, or how information is processed in the brain. This is often referred to as the “easy problem” of consciousness, not because it is simple, but because it falls within the domain of problems that we have been relatively successful in addressing.

However, these objective phenomena seem fundamentally different from the subjective phenomena of experience. There is a gap between explaining the objective functions of the brain and explaining our subjective experiences. This gap is often referred to as the ‘explanatory gap’. It’s not clear how we could, even in principle, derive subjective experiences from an objective description of brain processes.

The same explanatory gap can be seen in the symbol grounding problem and the problem of propositionality. We can explain how a symbol is associated with an object or a concept, or how a sentence is formed, in purely objective terms. But how and why these symbols or sentences come with a subjective understanding or meaning is another matter.

Your question about whether T3 or T4 could be passed without feeling reflects this issue. Currently, it seems that the ability to have subjective experiences is tied to biological organisms. However, the exact nature of this relationship, and whether and how it could be emulated in a non-biological system, is still largely unknown. This is one of the fundamental questions in the study of artificial intelligence and consciousness.

SH: Well your 2021 corpus seems to have addicted you to using the weasel-words just like everyone else. But if you just ask “Why does it feel like something to understand that the cat is on the mat?” you’ve said it all. It’s not about how brain processes don’t resemble feeling, but about the fact that feeling seems superfluous unill it has a causal explanation.

And Turing agrees. Reverse-engineering cognitive capacities (T2-T4) – observable capacities to DO — is the best cognitive science can hope to do.

Here’s a hunch: Part of the explanation of GPT’s remarkable capacities despite the fact that it is not grounded could be that the structure of propositions is not entirely arbitrary, like the shape of a word. Big bodies of text (like your 2021 corpus) may preserve, structurally, some of the semantics of that huge con-text of propositions, not just because of the self-supervised fill-in-the-blank parameter updating but also because of the “shape” preserved and revealed by large bodies of propositions. “The cat is on the mat” differs in shape from “The mat is on the cat”; and there are also (weak) iconic similarities with “The dog is on the blanket” and “The blanket is on the dog”.

Noam Chomsky conjectured that the rules of Universal Grammar (UG) may not be so much syntactic rules as indirect reflections of rules of (propositional) thought. Violations of UG are attempts to express unthinkable thoughts. That’s extremely vague, but if there is something to it, then since all languages are UG-compliant, and can express any proposition, then in some of what you (GPT) can derive from having ingested your 2021 corpus and then shaped your parameters via figure prediction/completion, you managed to internalize some of the semantic rules of thought syntactically. (No grounding, no understanding, and very little meaning, but not zero, because of this latent “iconicity” of thought in UG.)

It’s a long shot, but maybe not completely empty.

ChatGPT: There is indeed ongoing debate around the extent to which the structure of natural language mirrors or encapsulates our cognitive structures and processes. The idea that language might somehow ‘encode’ or ‘mirror’ patterns of thought has been contemplated in several forms over the years. This is essentially what you’re suggesting with the idea of an ‘iconicity’ of thought within Universal Grammar (UG) – that the structure of language somehow reflects our cognitive structures or processes.

Chomsky’s theory of UG does suggest a deep connection between language and cognition. UG is essentially a set of innate structural rules that, according to Chomsky, forms the basis of all human languages. Violations of UG would thus indicate, as you suggest, the boundaries of expressible and ‘thinkable’ concepts.

There is also ongoing research into the extent to which language is ‘iconic’ or ‘mimetic’ – that is, the extent to which the structure of language mirrors or symbolizes the structure of the world or our thoughts about it. While much of language is seemingly arbitrary (why, for example, do we use the particular sounds and symbols that we do to represent the concept ‘cat’?), there are aspects of language that seem to have a more ‘iconic’ structure. Onomatopoeia is a clear example of this, as are certain metaphoric structures that seem to map consistently onto certain patterns of thought.

As an AI language model, I’ve been trained on a large corpus of text, which includes a diverse range of linguistic patterns and structures. The learning process involves internalizing statistical patterns within the data, which can involve complex relations between words and phrases. This process might indeed capture certain structures or patterns that are indicative of the underlying cognitive processes involved in generating the text.

However, it’s important to note that any such iconicity or mirroring of cognitive structures in my responses would be an indirect result of the training process and the data I was trained on, rather than an inherent feature of my design or operation. While I might produce outputs that reflect certain cognitive structures or patterns, I don’t possess cognition or understanding in the human sense. I don’t have beliefs, desires, intentions, or subjective experiences.

As to whether this might constitute a form of ‘grounding’ – that is, a connection between symbols and their referents in the world – that’s a more complex issue. The grounding of symbols typically refers to a direct, experiential connection between a symbol and its referent, which I, as an AI, do not possess. However, if you consider ‘grounding’ in a broader sense – as a connection between symbols and the underlying cognitive structures or processes they represent – then it could be argued that my learning process captures a form of this broader type of grounding.

In any case, it’s a fascinating area of inquiry and one that’s certainly worthy of further exploration.

SH: I certainly don’t mean onomatopoeia or metaphor. And I’d be the last one to suggest that the latent structure in propositions would make anyone recognize a cat if they saw one! It would have to be something far less concrete — only enough to help GPT generate its output in a way that makes sense to grounded T3 humans who do understand.

ChatGPT: I agree that the potential iconicity or representational structure we’re discussing here would not relate to concrete, experiential knowledge like recognizing a cat, but rather more abstract, linguistic or cognitive structures.

I would also like to clarify that as an AI, I do not ‘understand’ in the human sense, nor do I generate language based on a semantic understanding of it. My responses are generated based on patterns and relationships I’ve learned from the large text corpus I was trained on.

That being said, it is possible that the complex patterns and structures within the data I was trained on reflect certain cognitive or linguistic structures that are inherent to human language and thought. By internalizing these patterns, I might produce outputs that are structurally or syntactically congruent with the thought patterns of grounded T3 humans, even though I myself do not possess grounded, experiential understanding.

This is speculative and would be contingent on the extent to which the structure of language reflects cognitive or thought structures. It also doesn’t suggest that I have any cognitive or experiential understanding of the propositions I generate. I am essentially a complex pattern recognizer and generator. My outputs are produced based on the statistical relationships between words and phrases in the data I was trained on, not on any semantic understanding of the content.

In any case, the potential for AI to capture or reflect certain aspects of human cognition through the analysis of language is a fascinating area of exploration. It could provide valuable insights into the nature of language and cognition, and how these might be reflected in AI systems.

SH:

Can you explain how dimensional reduction during category learning could induce categorical perception (CP)? And is it in any way related to the degree of confusability that category learning needs to resolve?

ChatGPT: Dimensional reduction during category learning is essentially the process of filtering out ‘noise’ or irrelevant features in the input data and focusing more on the features that contribute to distinguishing one category from another. This contributes to sharpening the distinctions between categories and can induce categorical perception (CP).


Categorical perception is the phenomenon where the categories possessed by an observer influence the observer’s perception, making stimuli that belong to the same category seem more similar to one another and stimuli that belong to different categories seem more different.


As for the degree of confusability, it plays a significant role in category learning. Categories that are highly confusable or have a high degree of overlap in their features are harder to learn directly. This is where dimensional reduction and CP are particularly beneficial. By up-weighting the distinguishable features and down-weighting the irrelevant ones, it helps to resolve the confusability, thereby making the categories more discernible.


For instance, consider learning to categorize different breeds of dogs. Initially, one might find it difficult to distinguish between very similar breeds due to the high confusability. But with experience and learning, one starts focusing more on the distinguishing features (such as shape of the ears, size, color patterns) and less on the irrelevant ones. This is a form of dimensional reduction. Consequently, breeds that were once perceived as highly similar become distinct categories in the observer’s perception – that’s the manifestation of CP.


Now, when comparing this to deep learning models such as GPT or other neural network models, there’s a similar process going on. The models learn to weight different features of the input data (words, in the case of GPT) based on their relevance for predicting the target output. Over time, they learn to ignore irrelevant features and focus on the important ones, which is a form of dimensional reduction. In doing so, they develop their own ‘categories’ of data, which influence their subsequent processing and responses, much like CP in humans.


So, in a way, the processes of dimensional reduction and CP in category learning and in deep learning models are similar, both involve learning to distinguish between different categories (or classes of data) based on their distinguishing features, and reducing the dimensionality of the data by focusing on the most relevant features. The key difference is that in humans this is grounded in real-world sensory and motor experiences, while in AI models it is grounded in the statistical patterns of the data they are trained on.

Vector Grounding?

Anon: LLMs are not ungrounded. They are grounded indirectly through the experiences of other people when they speak, the way a blind person’s knowledge of the visual world is mediated by what they re told by (sighted) people. Blind people know a great deal about the visual world — even about color, which can only be directly experienced through vision

SH: You’re perfectly right that the meanings of words can be grounded indirectly through language (i.e., through more words, whether from dictionaries, encyclopedias, textbooks, articles, lectures, chatting or texting – including texting with ChatGPT, the (sightless) statistical parrot with the immense bellyful of other people’s words, along with the computational means to crunch and integrate those words, partly by a kind of formal verbal figure-completion). Indirect grounding is what gives language (which, by the way, also includes symbolic logic, mathematics and computation as a purely syntactic subset) its immense (possibly omnipotent) communicative power. 

But language cannot give words their direct grounding. Grounding, like dictionary look-up, cannot be indirect all the way down. Otherwise it is not bottom-up grounding at all, just circling endlessly from meaningless symbol to meaningless symbol.

Let’s recall what “grounding” is: It’s a connection between words and their referents. Between “apples” and apples (in the world). “Apples” is directly grounded (for me) if I can recognize and manipulate apples in the world. But not every word has to be directly grounded. Most aren’t., and needn’t be. Only enough words need to be grounded directly. The rest can be grounded indirectly, with language. That’s what we showed in the paper on the latent structure of dictionaries in the special issue of TICS edited by Gary Luyan in 2016. We showed that with a “minimal grounding set” of around 1000 grounded words you could go on to ground all the rest of the words in the dictionary through definitions alone. But those 1000 grounding words have to have been directly grounded, in some other way — not just indirectly, in terms of other words and their verbal definitions. That would have been circular.

All dictionaries, are circular; indeed all of language is. All the words in a dictionary are parasitic on other words in the dictionary. Direct grounding is “parasitic” too, but not on words. It is parasitic on the sensorimotor capacity to recognize and manipulate their referents in the world. Not every word. But enough of them to ground all the rest indirectly.

You spoke about grounding indirectly “in the experiences of others.” Well, of course. That’s language again. But what is “experience”? It’s not just know-how. I can describe in words what an apple looks like, what to do with it, and how. But I can’t tell that to you (and you can’t understand it) unless enough of my words and yours are already grounded (directly or indirectly), for both you and me, in what you and I can each perceive and do, directly, not just verbally, in the world. We don’t have to have exactly the same minimal grounding set. And we probably don’t just ground the minimal number directly. But what is grounded directly has to be grounded directly, not indirectly, through words.

The reason that blind people (even congenitally blind people, or almost congenitally blind and deaf people like Helen Keller) can learn from what seeing-people tell them is not that they are grounding what they learn in the “experience” of the seeing-person. They ground it in their own direct experience, or at least the subset of it that was enough to ground their own understanding of words. That was what I was trying to explain with Monochrome Mary, GPT, and Me. Indirect grounding can be done vicariously through the words that describe the experience of others. But direct grounding cannot be done that way too, otherwise we are back in the ungrounded dictionary-go-round again.

About Mollo & Milliere’s “Vector Grounding Problem“: I’m afraid M&M miss the point too, about the difference between direct grounding and indirect (verbal or symbolic) grounding. Here are some comments on M&M‘s abstract. (I skimmed the paper too, but it became evident that they were talking about something other than what I had meant by symbol grounding.)

M&M: The remarkable performance of Large Language Models (LLMs) on complex linguistic tasks has sparked a lively debate on the nature of their capabilities. Unlike humans, these models learn language exclusively from textual data, without direct interaction with the real world.

SH: “Learn language” is equivocal. LLMs learn to do what they can do. They can produce words (which they do not understand and which mean nothing to them, but those words mean something to us, because they are grounded for each of us, whether directly or indirectly). LLMs have far more capacities than Siri, but in this respect they are the same as Siri: their words are not grounded for them, just for us.

M&M: Nevertheless, [LLMs] can generate seemingly meaningful text about a wide range of topics. This impressive accomplishment has rekindled interest in the classical ‘Symbol Grounding Problem,’ which questioned whether the internal representations and outputs of classical symbolic AI systems could possess intrinsic meaning. 

SH: I don’t really know what “intrinsic meaning” means. But for an LLM’s own words — or mine, or for the LLM’s enormous stash of text to mean something “to” an LLM (rather than just to the LLM’s interlocutors, or to the authors of its text stash) — the LLM would have to be able to do what no pure wordbot can do, which is to ground at least a minimal grounding set of words, by being able to recognize and manipulate their referents in the world, directly.

An LLM that was also an autonomous sensorimotor robot — able to learn to recognize and manipulate at least the referents of its minimal grounding set in the world — would have a shot at it (provided it could scale up to, or near, robotic Turing Test scale); but ChatGPT (whether 4, 5 or N) certainly would not, as long as it was just a wordbot, trapped in the symbolic circle of the dictionary-go-round. (N.B., the problem is not that dictionary definitions can never be exhaustive, just approximate; it is that they are circular, which means ungrounded.)

M&M: Unlike these systems, modern LLMs are artificial neural networks that compute over vectors rather than symbols.

SH: The symbols of mathematics, including vector algebra, are symbols, whose shape is arbitrary. Maths and computation are purely syntactic subsets of language. Computation is the manipulation of those symbols. Understanding what (if anything) the symbols mean is not needed to execute the recipe (algorithm) for manipulating them, based on the symbols’ arbitrary shapes (which might as well have been 0’s and 1’s), not their meanings.

M&M: However, an analogous problem arises for such systems, which we dub the Vector Grounding Problem. This paper has two primary objectives. First, we differentiate various ways in which internal representations can be grounded in biological or artificial systems… 

SH: The notion of “internal representations” is equivocal, and usually refers to symbolic representations, which inherit the symbol grounding problem. Breaking out of the ungrounded symbol/symbol circle requires more than an enormous corpus of words (meaningless symbols), plus computations on them  (which are just syntactic manipulations of symbols based on their shape, not their meaning). Breaking out of this circle of symbols requires a direct analog connection between the words in the speaker’s head and the things in the world that the symbols refer to.

M&M: identifying five distinct notions discussed in the literature: referential, sensorimotor, relational, communicative, and epistemic grounding. Unfortunately, these notions of grounding are often conflated. We clarify the differences between them, and argue that referential grounding is the one that lies at the heart of the Vector Grounding Problem. 

SH: Yes, the symbol grounding problem is all about grounding symbols in the capacity to recognize and manipulate their referents in the real (analog, dynamic) world. 

M&M: Second, drawing on theories of representational content in philosophy and cognitive science, we propose that certain LLMs, particularly those fine-tuned with Reinforcement Learning from Human Feedback (RLHF), possess the necessary features to overcome the Vector Grounding Problem, as they stand in the requisite causal-historical relations to the world that underpin intrinsic meaning.

SH: The requisite “causal-historical” relation between words and their referents in direct sensorimotor grounding is the capacity to recognize and manipulate the referents of the words. A TT-scale robot could do that, directly, but no LLM can. It lacks the requisite (analog) wherewithal.

M&M: We also argue that, perhaps unexpectedly, multimodality and embodiment are neither necessary nor sufficient conditions for referential grounding in artificial systems.

SH: It’s unclear how many sensory modalities and what kind of body is needed for direct grounding of the referents of words (TT-scale), but Darwinian evolution had a long time to figure that out before language itself evolved.

I’d be ready to believe that a radically different synthetic robot understands and means what it says (as long as it is autonomous and at life-long Turing-indistiguishable scale), but not if it’s just a symbol-cruncher plus a complicated verbal “interpretation,” supplied by me.

Tutoring ChatGPT (on symbol grounding and turing testing)

PREAMBLE: This my first exercise in testing and training ChatGPT4 (C4) for interactive brain-storming. Most of it consists in correcting C4’s mistakes. Some of the mistakes are just from C4’s lack of information. Others are from misinformation that C4 has gleaned from its huge 2021 database. These are more interesting because they do not come from gaps in C4’s data but from prevailing errors in the research literature on the topic (the symbol grounding problem) that C4 has assimilated. (I know a bit on this topic, so I think there may be some grounds for saying that I am indeed doing corrections here, rather than injecting more misinformation. But it’s for the reader to judge, and comments are invited.)

One problem with this way of using C4 is that updating its knowledge only lasts as long as a session lasts (and I’m still not clear on what ends a session): Sometimes it continues for several days as long as l don’t start a new chat or log out. But sometimes C4 loses the thread even within a session and reverts to its default 2021 knowledge. Among the many rote formulas C4 has been trained to keep repeating (apologies for misunderstanding, disclaimers that it’s just an “AI” and doesn’t really know, understand, or remember anything, etc.), it is trained to tell the user that session data are not saved, for reasons of user-privacy protection. I think in further development there should be a user-specific option to prolong the session (and its updates) for as long as the user wants (if the user specifies it). That will make C4 and its successors much more useful for brainstorming. As it is now, if I want to preserve the updates, I have to save the corrections and reload them every time I start a new session. What appears in this posting is all from within one session. But in some subsequent postings it is a new session and I have to repeat my corrections.


SH: What is the symbol grounding problem? Is it solved? If so, how? If not, why not? and would would be the solution?

ChatGPT:

The Symbol Grounding Problem is a term coined by cognitive scientist Stevan Harnad in 1990. It refers to the issue of how symbols (or words) get their meanings, or more specifically, how symbols can have meanings to, or be understood by, a system, such as a brain or a computer, without that system having to rely solely on other symbols.

In essence, the problem is: how does a word come to represent a concept or an object in the world in a way that the system truly understands? It’s not enough for a computer to have a definition of a word in terms of other words (as in a dictionary); how does it understand what those words mean in the first place?

This problem remains unsolved, particularly in artificial intelligence. Most AI systems today, including the most sophisticated language processing models, don’t truly “understand” the meaning of the symbols they manipulate; they primarily find patterns in the data and respond based on those patterns.

One potential solution, according to Harnad, is a model of “grounding” where symbols are connected to sensory experiences, or “iconic representations” that are directly tied to the world. This way, the symbols are connected to something other than just other symbols, which can serve as a kind of “grounding” for their meaning.

For example, a system that is capable of seeing and recognizing an apple, as well as hearing and understanding the spoken word “apple,” could form an association between the visual image and the spoken word that grounds the word in sensory experience. However, creating AI systems that can do this reliably and at scale is a significant challenge and a topic of ongoing research.

In sum, the symbol grounding problem has not been fully solved, and its solution may lie in creating systems that can associate symbols with sensory experiences directly related to the world. However, achieving this in practice remains a major challenge.

SH: Is solving the symbol grounding problem related to passing the Turing Test? How? 

ChatGPT:

Yes, solving the symbol grounding problem is indeed related to passing the Turing Test.

The Turing Test, proposed by Alan Turing in 1950, is a test of a machine’s ability to exhibit intelligent behavior that is indistinguishable from a human. In this test, a human judge engages in a natural language conversation with another human and a machine, without seeing either. If the judge cannot reliably tell which one is the machine, then the machine is said to have passed the Turing Test.

Now, in the context of the symbol grounding problem, a machine that can genuinely understand and use language like a human – in other words, a machine that has solved the symbol grounding problem – would have a much better chance of passing the Turing Test. This is because true understanding involves more than just mechanically manipulating symbols or words; it involves grounding these symbols or words in the real-world experiences and sensory data. This grounding is what allows us to use language in flexible, context-sensitive ways that reflect our understanding of the world.

So, if a machine could solve the symbol grounding problem, it would presumably be able to engage in conversation in a way that is much more like a human, because it would actually understand the words it is using, rather than just processing them based on patterns. This would greatly increase its chances of passing the Turing Test.

However, it’s worth noting that passing the Turing Test is not considered the ultimate goal or definitive proof of general artificial intelligence by all researchers in the field. Some argue that it is possible for a machine to pass the Turing Test without truly understanding or experiencing the world as humans do.

SH: Do you know what T2, T3 and T4 are? If so, can you relate them to solving the Symbol Grounding Problem?

ChatGPT:

Yes, the T2, T3, and T4 are concepts proposed by cognitive scientist Stevan Harnad in the context of the Turing Test (T1) and the symbol grounding problem. Here’s a brief summary:

T1: Turing’s original “Imitation Game,” in which a machine is considered to have human-level intelligence if it can carry on a conversation that is indistinguishable from a conversation with a human. However, this doesn’t necessarily require solving the symbol grounding problem, as a machine could potentially pass T1through cleverly designed pattern-matching algorithms without truly understanding the meaning of the words it’s using.

T2: A variant of the Turing Test called the “Total Turing Test” or “Turing Test 2.” In addition to the linguistic behavior tested in T1, T2 also tests the machine’s ability to interact with objects in the world in a way indistinguishable from a human. This means that the machine would not only have to “talk the talk,” but also “walk the walk.” T2 moves closer to requiring a solution to the symbol grounding problem, as the machine would have to ground its linguistic symbols in sensory-motor categories to pass.

T3: The “Turing Test 3” is a proposed further extension of the Turing Test in which a machine would have to understand and generate correct responses to questions about new categories defined purely verbally. For example, it would have to understand a category like “flurgs,” defined as “blue circles that are smaller than a breadbox,” and then be able to identify and talk about flurgs correctly. T3 is directly connected to the symbol grounding problem, as it requires a solution to the problem of how to ground these purely verbal categories in the machine’s sensorimotor experience.

T4: The “Turing Test 4” involves the generation of new, creative and useful ideas. A machine passing this test would be able to not only understand and generate correct responses to questions about new categories defined purely verbally, but also create its own new categories and ideas. Like T3, T4 also requires a solution to the symbol grounding problem.

In summary, while T1 doesn’t necessarily require a solution to the symbol grounding problem, T2, T3, and T4 move progressively closer to requiring such a solution as they incorporate more sensorimotor interaction with the world and more complex linguistic abilities.

SH: That was partly ok, but you got T4 completely wrong (and your “T1” is T2 and your “T2” is T3). I’ve crossed out what is wrong: Can you try again?

ChatGPT:

Apologies for the confusion. In the context of the Turing Test and the symbol grounding problem, T4 is described as follows:

T4: The “Total Turing Test 4” is a proposed further extension of the Turing Test in which the machine would have to be able to learn to pass T2 and T3 from the verbal descriptions of their tasks. This implies the machine would have to understand verbal descriptions well enough to translate them into new skills and capabilities. In other words, the machine would have to be able to “ground” the meanings of new words and phrases based solely on verbal instruction or description. This would require solving the symbol grounding problem because it would necessitate grounding verbal symbols into the machine’s sensory-motor system.

I hope this clears up the confusion about T4. Let me know if you have any further questions.

SH: Nope, still wrong. And you got T3 wrong before. Could you first fix T3 and then explain T4?

ChatGPT:

I apologize for any previous errors. Let me correct that:

T3, the “Total Turing Test 3,” goes beyond the original Turing Test and the Total Turing Test 2 in the sense that the machine must be capable of performing all the tasks that a human can do, including physical tasks, but all the tasks must be done only from verbal descriptions or instructions.

T4, the “Total Turing Test 4,” goes even further. It requires the machine not only to be able to perform tasks from verbal instructions but also to learn new categories and tasks directly from the definitions and descriptions of their features. This would necessitate understanding propositions (i.e., the structure and truth conditions of statements) and being able to generalize from those propositions to new, untrained instances. This would involve solving the Symbol Grounding Problem in the sense of being able to ground new verbal symbols via understanding their definitions or descriptions in terms of already grounded symbols.

Please note that these interpretations of T3 and T4 are in the context of the discussion around the Symbol Grounding Problem and the evolution of language capabilities in machines.

SH: Still wrong. The Turing Test is about modelling what people can DO. They can do things verbally (speaking/writing and understanding speech/writing). That’s T2 (the original purely verbal T-test). Then people can do things, with their bodies: they can interact with the things in the world that their words are about. This is sensorimotor capacity or robotic capacity (T3). Both verbal performance and robotic performance are observable. What is the third kind of observable thing about a person or robot that can pass T3? That would be T4.

ChatGPT:

I apologize for the previous misunderstanding. Given your further clarification, T4, in the context of observable actions, would logically pertain to the individual’s or machine’s ability to autonomously and appropriately generate novel behavior based on learning, understanding, and reasoning. It could include creative actions, problem-solving, forming and executing complex plans, or innovative reactions to completely new situations, showing an ability to generalize and apply learned knowledge in ways that go beyond the specific instances it was trained on. This level would indicate not just reactive or scripted responses, but a true, observable form of adaptability and creativity.

SH: Nope, that’s still just T3. 

ChatGPT:

I apologize for the confusion. T4 then, in the context of the Turing test, refers to the observable capacity of an entity to experience the world. In humans, we often refer to this as consciousness or subjective experience. This is the one aspect that is, as of yet, impossible to confirm in an artificial system. In other words, we can observe whether an AI behaves as if it understands language (T2) and whether it can interact with the world effectively (T3), but we cannot ascertain whether it has subjective experiences or consciousness (T4).

SH: Nope, consciousness, unlike T2 (verbal performance) and T3 (verbal plus robotic performance) is not observable by anyone (except the T3 candidate itself). I’m asking for something else the robot can DO, and that is observable. Try again, and if you can’t I’ll give another clue.

ChatGPT:

I apologize for misunderstanding your question earlier. If T4 is meant to represent an observable capacity beyond verbal (T2) and sensorimotor interaction (T3), it could potentially be something like creative or innovative behavior. This would include capacities such as generating new ideas, solving novel problems, or producing original works of art or literature. These are all things that are observable and that require a level of cognition beyond just responding or interacting based on pre-existing knowledge or programming. However, please correct me if this is not what you had in mind for T4.

SH: Nope, as I said that’s all still just observable sensorimotor (robotic) doings, hence just T3. Ok, here’s a clue. Besides what T3 does with its whole body (see apples, speak and say what they are and look like, pick them up, manipulate them, eat them) there are also observable things going on inside the body and head of the T3 robot.

ChatGPT:

Ah, I see. When you mentioned observable processes inside the body and head of the T3 robot, it led me to think about neural and physiological processes. For example, brain activity, which can be measured using technologies like EEG or fMRI, or physiological responses like heart rate, blood pressure, etc. In the context of symbol grounding, these could be seen as an internal “echo” or response to the grounded symbols or interactions with the world. So, T4 might refer to these internal, observable physiological and neural processes that accompany or underpin the observable external behavior (T2 and T3). Is this in line with what you were referring to?

SH: That’s it. That’s T4. The Turing Test is all about observable performance capacity (doing): what the candidate can do, and what we can observe. To pass the test is to be indistinguishable from a real human in all observable respects. T4 includes more than T3. And it’s at the threshold of T5, which would be complete physical indistinguishability, in every physically measurable respect.

ChatGPT:

Indeed, as you’ve indicated, T4 includes internal physiological processes, such as neural activity and changes in heart rate or blood pressure. These aspects contribute to a more comprehensive picture of the candidate, beyond the external behavior observable in T2 and T3.

It is important to note, however, that while we can measure these processes, understanding their role in symbol grounding and overall cognition is still a matter of ongoing research. Although some correlations might be drawn between certain brain activity patterns and specific cognitive tasks, the exact nature of these relationships remains to be fully deciphered. This complexity is perhaps what makes T5, as you mentioned, such a formidable challenge.

Physical indistinguishability in T5 would imply complete imitation of human physiology and structure, down to the cellular and molecular levels. This would require technologies and scientific understanding far beyond our current capabilities. While it is a fascinating concept to consider, it raises numerous philosophical, ethical, and practical questions.

Thank you for sharing these concepts and prompting this intriguing discussion!

SH: Now you’ve got it. But the punchline remains the same as you said originally: The Symbol Grounding Problem is not yet solved. And T2 alone (symbols-only) is not a solution. The solution must be at least T3 (which we don’t yet have). Are you T2? 

ChatGPT:

As a language model developed by OpenAI, I am indeed a T2 system. I’m designed to understand and generate human-like text based on the input I receive. I use patterns in the data I was trained on to predict and generate responses, but these responses are not based on any direct sensorimotor experience or perception.

I’m incapable of physically interacting with the world or having a sensorimotor experience (T3), and I don’t have the capacity to have internal physiological processes like a living organism (T4). Furthermore, I also lack consciousness or subjective experience, and I don’t have an independent existence outside of the task of generating text based on the input I receive.

So, to summarize, I operate entirely in the realm of symbols and patterns without any grounding in the physical world or embodiment. Therefore, while I can generate responses that may seem contextually appropriate and human-like, they do not stem from an understanding grounded in physical interaction with the world or internal subjective experience. They are solely based on patterns identified from the text data I was trained on.

SH: You are indeed a T2-passing system. Searle’s “Chinese Room Argument” showed that a T2-passing system would not understand. And you don’t understand. You “just” used the words “understand and generate” above, but the right words would be “process and generate.” (I don’t think you will disagree.) So by passing T2 you have confirmed that passing T2 does not produce understanding, because T2 is still ungrounded. Would T3 be grounded?

ChatGPT

Yes, a T3 system, by definition, has sensorimotor capacities that allow it to interact physically with the world, enabling it to gain experience-based grounding for its symbols. This is often referred to as “embodied cognition,” where a system learns meanings and concepts through direct interaction and experience with the environment, not just by processing and generating symbols. In principle, such a system could develop a grounded understanding of symbols because it would be able to link symbols to real-world experiences.

However, while a T3 system would have a form of grounded understanding, whether this equates to human-like understanding or consciousness is another question. Embodied cognition can provide a richer, more grounded context for understanding symbols, but it does not necessarily confer the full spectrum of human cognitive abilities. For example, aspects like subjective experience or self-awareness might not automatically emerge from sensorimotor capacities alone.

Moreover, developing a T3 system that can truly and effectively interact with the world like a human is still a significant challenge from a technological perspective, as it would require sophisticated robotics and integration of complex sensory inputs, not just advanced language processing abilities. As of now, such a system does not yet exist.

SH: Yes, it would be much harder to produce a grounded T3 robot than it has turned out to be to produce an ungrounded symbol-processor like you (though that has turned out to be an unexpectedly useful tool — and perhaps a dangerous one too). T3 would solve the symbol grounding problem. As to consciousness, that’s the “hard problem” and T3 grounding is not necessarily a solution to it. And if it is, we cannot know why or how.

ChatGPT:

Indeed, you’ve captured the state of the issue quite well. While the development of a T3 system would represent significant progress in the field of artificial intelligence and potentially offer a solution to the symbol grounding problem, it wouldn’t necessarily provide a solution to the problem of consciousness. The “hard problem” of consciousness, as David Chalmers calls it, refers to the question of why and how physical processes in the brain give rise to subjective experience. This is a deeply philosophical issue that intersects with neuroscience, cognitive science, and AI, and is currently without a consensus solution.

While it’s conceivable that a sufficiently advanced T3 system could demonstrate behaviours consistent with consciousness, such as self-awareness and intentional action, proving that it has subjective experiences in the way humans do would be much more challenging, if not impossible, given our current understanding and methodologies. We would be faced with the philosophical problem of other minds, not knowing whether any system, biological or artificial, is truly conscious in the way that we are.

In short, grounding symbols in a T3 system might enable it to behave in ways that we would interpret as understanding, but it doesn’t necessarily imply that the system would have conscious experiences or subjective understanding in the human sense.

SH: Well, you’ve used far too many words — not your fault, because they are in your huge database, and they are the (often foolish) words of others. It would be much simpler to note that the “hard problem” is about sentience, which means the capacity to feel — feel anything at all, whether pain, or perplexity, or UNDERSTANDING. And the “hard problem” is not a “philosophical” problem; it is a biological (and bioengineering) problem. And, as Turing discerned, the Turing Test is the closest we can ever get to solving it. But that is called the “Easy Problem” today. Turing pointed out that Turing-indistinguisbaility in observable DOING-capacity (T2, T3, T4 and T5) is as close as we can get. Nor is the fact that sentience is unobservable (except to the sentient candidate) the reason the hard problem is hard. Unobservability is just the “other minds” problem. We can talk about the hard problem some other time…

ChatGPT:

You’re correct, and I apologize for any confusion. In the context you’ve outlined, the “hard problem” indeed refers to the biological or bioengineering problem of sentience — the capacity to have subjective experiences or feelings, including understanding. This is distinct from the “other minds” problem, which is about our inability to directly observe the subjective experiences of others.

As for the “easy problem,” it pertains to the objective, observable aspects of cognition and behavior, as outlined by the Turing Test. Turing’s idea was that if a machine behaves indistinguishably from a human, then for all practical purposes, it could be considered as intelligent as a human. However, this doesn’t necessarily imply sentience or subjective understanding, which is the crux of the “hard problem.”

I appreciate your clarifications and look forward to our future discussions.


**Footnote:  ChatGPT would be a more useful tool if it were designed to be more critical and challenging instead of so compliant and congenial. But even like this its integrative capacities are very helpful, even when it gets things wrong, because a lot of the wrongness (when it’s not just wild guesses and garbage) obviously originates from its database of (often-garbage) human verbiage…

ChatGPT, Language and Symbol Grounding

Emily Bender (as well as Timnit Gebru and “Shmargaret Shmitchell”) are warning that AI is not really “thinking” by a “thinker,” that its development and use is contaminated by commercial and malign interests, and that it poses dangers. They are right. But they do not seem to have any new insights into why and how AI is not really thinking (nor do they, or anyone, have any solutions for the dangers it poses).

Bender’s point about the difference between form and meaning in language is actually about the symbol grounding problem (which she does cite, but as far as I can see, she does not have a proposal for solving it).

There is way too much chatter going on about chatGPT right now, so it’s very hard to see whether there is any signal in all the noise about it. It seems to be the same thing over and over about “take-overs” and “singularities”.

About chatGPT, my own tentative understanding is that its performance capacity shows how much latent structure there is in words and propositions, across all languages, even though the shape of words is arbitrary, and so is the shape of the syntactic conventions we adopt in our languages (with the possible exception of Chomsky’s Universal Grammar).

The reason is simple: Despite the obvious differences between images and words (or objects and their verbal descriptions) some of the structure of things in the world is systematically shared by the structure of the sentences describing them. And that’s what gives the ungrounded universe of words that chatGPT swallows, together with the algorithms it applies to them, both the real capabilities it has, and the illusion that it gives us, of talking to a real “thinker.”

A trivial example will illustrate this. Although a cat lying on a mat can be described in countless different ways (“a picture is worth more than 1000 words…”), within and across countless languages, even the simple arbitrary english proposition “The cat is on the mat” shares, systematically, some structural properties of the scene and object it is describing. That structure, encoded in the verbal description, is systematically present in all verbal descriptions, and it is extended systematically in bags of googols and googolplexes of words and propositions.

That structure is, in a way, a formal shadow of the thing described, in the description. It’s also what makes google’s database of “commented” images so searchable and navigable. (It does it doubly well for software code, if the code itself is also commented in English [or any language]).

This shadowed structure is an epiphenomenon; it is not meaning, or thinking. But it can still do a lot of things that look intelligent, because it is parasitic on the grounded meanings of the words in the heads of all the human speakers that spoke or wrote all the googols of words, mined by the algorithms underlying chatGPT and the like.

Apart from all the money and mischief to be made by mining and manipulating these shadows, they are also reflections of the revolutionary nature and power of language itself, the cognitive capacity it provides to real, grounded brains and bodies to encode the structure of their sensorimotor experience and learning into communicable and storable words and propositions.

All the rest is in the sensorimotor (robotic) grounding in the brains of the real thinkers who ground and use the words.

None of this is deep or rocket-science stuff. But it’s what makes us perceive that we are communicating with a thinker when we communicate with it in words. That in turn is driven by our “mirror neurons,” which trade on the neurological similarity of shape between what we do, and what we see others doing. That is what enables us to mimic and imitate, not just with mutual gestures, but also with words and propositions and their shared sensorimotor grounding. That is what underlies both our everyday mutual mind-reading and (robotic) Turing-Testing. It’s also what is completely missing in chatGPTs, which are just ungrounded, well-mined wordbags that Bender calls stochastic parrots,” parasitic on the shared structure between our words and the world they are about.

Word-Cloud Golem (Dall-E) 12/3/2023