The good thing about a blog is that you can answer questions even when you haven’t been asked. A friend just sent me What We Believe But Cannot Prove: Today’s Leading Thinkers on Science in the Age of Certainty (edited by John Brockman) Harper 2006. But before I even open it – well I did peek and saw it’s mostly cog-sci light-weights rather than hard-sci heavy-hitters – I wanted to put it on record that Descartes already did a good job on this in the Age of Enlightenment.
Descartes asked the hard questions about certainty (“what can I know for sure?” “what is open to doubt?”) and his conclusion seems to be just as certain today: There is only one other thing I can know for sure, apart from what can be proved (as in logic and mathematics), and that is the fact that I feel (if/when I feel). Descartes overstated it, suggesting that when I’m thinking, I can’t doubt that I’m existing too (“Cogito Ergo Sum”), but that has always been much too theory-ridden and equivocal. What’s meant by “I,” or even by “existence”? Big words. But in baby-talk, it’s just as self-contradictory to say it’s true that “I am not feeling” when I am in fact feeling (“sentitur ergo sentitur”) as it is to say that both P and not-P are true. (No need to “define” feeling by the way; we all know what it feels like to feel, and anyone who says otherwise is just bluffing. [Pinch him!].)
But that’s all. Nothing else is certain but those two kinds of truths (the formal truths of mathematics, provably true on pain of contradiction, and the self-demonstrating truth of experiencing itself – which does not, by the way, mean that experience conveys any other certainties). All else is mere probability. In particular, all the truths of science. (It’s certain that things feel like whatever they feel like, that they seem whatever they seem; anyone who doubts that is on a fool’s errand. But whether they really are the way they seem is an entirely different matter.)
But in what sense do we live in the age of certainty? Because of the naïve scientism of some of us (“scientists have proved that…”)? or the even more naïve fideism of others (“credo quia absurdum”)?
Now I shall peek in the book and see what these bright lights have to say…
Stevan Harnad