Genius_ The Life and Science of Richard Feynman - James Gleick [222]
Why did she slip on the ice? Well, ice is slippery. Everybody knows that—no problem. But you ask why is ice slippery… . And then you’re involved with something, because there aren’t many things as slippery as ice… . A solid that’s so slippery?
Because it is in the case of ice that when you stand on it, they say, momentarily the pressure melts the ice a little bit so that you’ve got an instantaneous water surface on which you’re slipping. Why on ice and not on other things? Because water expands when it freezes. So the pressure tries to undo the expansion and melts it… .
I’m not answering your question, but I’m telling you how difficult a why question is. You have to know what it is that you’re permitted to understand … and what it is you’re not.
You’ll notice in this example that the more I ask why, it gets interesting after a while. That’s my idea, that the deeper a thing is, the more interesting… .
Now when you ask why two magnets repel, there are many different levels. It depends whether you’re a student of physics or an ordinary person who doesn’t know anything.
If you don’t know anything at all, about all I can say is that there’s a magnetic force that makes them repel. And that you’re feeling that force. Well, you say that’s very strange because I don’t feel a force like that in other circumstances… . You’re not at all disturbed by the fact that when you put your hand on the chair it pushes you back. But we found out by looking at it that that’s the same force… . It turns out that the magnetic and electric force with which I wish to explain these things is the deeper thing that we would start with to explain many other things… .
If I said that magnets attract as if they were connected with rubber bands, I would be cheating you, because they’re not connected with rubber bands… . If you were curious enough you’d ask me why rubber bands tend to pull back together again, and I would end up explaining that in terms of electrical forces—which are the very things I was using the rubber bands to explain, so I have cheated very badly, you see.
So I am not going to be able to give you an answer to why magnets attract. Except to tell you that they do … I really can’t do a good job—any job—of explaining the electromagnetic force in terms of something you’re more familiar with, because I don’t understand it in terms of anything else that you’re more familiar with.
He sat back and grinned.
To the professionals Feynman’s musings were not philosophy but a charmingly naive folk wisdom. He was both after and ahead of his time. Academic epistemology was still wrestling with unknowability. What choice did they have, in light of scientific relativity and uncertainty, the abandonment of strict causality and the pervasiveness of ever-qualified probabilities? No more certainties, no more absolutes. The Harvard philosopher W. V. Quine mused, “I think that for scientific or philosophical purposes the best we can do is give up the notion of knowledge as a bad job… .” Not knowing had its ironies as well as its pleasures. For philosophers this was “the post-scholastic era,” as a later physicist, John Ziman, put it, “when it seemed essential to (dis)prove the peculiar (un)reality of scientific knowledge (theories/facts/data/hypotheses) by analysing (deconstructing) the arguments on which it was (supposedly) based.” Scientists themselves, in the knowledge business, had no use for this mode of discourse. Judged by results, their understanding of nature seemed richer and more efficacious than ever, the quantum paradoxes notwithstanding. They had rescued knowledge from uncertainty after all. “The scientist has a lot of experience with ignorance and doubt and uncertainty,” Feynman said. “… we take it for granted that it is perfectly consistent to be unsure—that it is possible to live and not know. But I don’t know whether