Tuesday, March 20, 2012

Did Herman Weyl really prefer Beauty to Truth?

There's a famous quotation attributed to the mathematician and physicist Hermann Weyl:
My work always tried to unite the true with the beautiful; but when I had to choose one or the other, I usually chose the beautiful.
Contemporary physicists (in particular String Theorists) have been known to go on about how "beautiful" they find some theory (typically their own haha) especially when hard evidence to support that theory is nowhere in sight. There's usually a kind of tacit implication that the expositor is better in touch with the mysteries of the cosmos than the great unwashed who don't appreciate the "beauty" of their revolutionary new theory. After all the great Weyl valued Beauty over Truth didn't he? Peter Woit points out in a recent blog post Dyson on Fringe Physics, String Cosmology and Hermann Weyl that the context of that quote is quite significant and it's more than a little misleading to take it out of that context. It was published in a paper by Freeman Dyson in Nature on the occasion of Weyl's passing:
Characteristic of Weyl was an aesthetic sense which dominated his thinking on all subjects. He once said to me, half joking, ‘My work always tried to unite the true with the beautiful; but when I had to choose one or the other, I usually chose the beautiful’. This remark sums up his personality perfectly. It shows his profound faith in an ultimate harmony of Nature, in which the laws should inevitably express themselves in a mathematically beautiful form. It shows also his recognition of human frailty, and his humor, which always stopped him short of being pompous.
A particular example of this was Weyl's gauge theory of gravity, which turned out to be fatally flawed, but which he was reluctant to abandon because of its beauty. As it turns out, some of the principles that he used in this unworkable theory of gravity found use later on in other areas of physics. However, just because Weyl liked one of his theories that didn't work out at first, but some of the ideas later proved to be useful, doesn't mean the odds are particularly good at all for contemporary theorists with pet theories they claim to be beautiful. The libraries have aisles and aisles full of journals and dissertations which haven't turned out to be significant and it's extremely likely that the vast majority of them will never turn out to significant, not least because they often contradict each other!
The rest of Woit's blog post is worth reading too, as usual.