One evening a few years ago I was with some other faculty members at the University of Texas, telling a group of undergraduates about work in our respective disciplines. I outlined the great progress we physicists had made in explaining what was known experimentally about elementary particles and fields—how when I was a student I had to learn a large variety of miscellaneous facts about particles, forces, and symmetries; how in the decade from the mid-1960s to the mid-1970s all these odds and ends were explained in what is now called the Standard Model of elementary particles; how we learned that these miscellaneous facts about particles and forces could be deduced mathematically from a few fairly simple principles; and how a great collective Aha! then went out from the community of physicists.
After my remarks, a faculty colleague (a scientist, but not a particle physicist) commented, “Well, of course, you know science does not really explain things—it just describes them.” I had heard this remark before, but now it took me aback, because I had thought that we had been doing a pretty good job of explaining the observed properties of elementary particles and forces, not just describing them.
I think that my colleague’s remark may have come from a kind of positivistic angst that was widespread among philosophers of science in the period between the world wars. Ludwig Wittgenstein famously remarked that “at the basis of the whole modern view of the world lies the illusion that the so-called laws of nature are the explanations of natural phenomena.”
It might be supposed that something is explained when we find its cause, but an influential 1913 paper by Bertrand Russell had argued that “the word ‘cause’ is so inextricably bound up with misleading associations as to make its complete extrusion from the philosophical vocabulary desirable.” This left philosophers like Wittgenstein with only one candidate for a distinction between explanation and description, one that is teleological, defining an explanation as a statement of the purpose of the thing explained.
E.M. Forster’s novel Where Angels Fear to Tread gives a good example of teleology making the difference between description and explanation. Philip is trying to find out why his friend Caroline helped to bring about a marriage between Philip’s sister and a young Italian man of whom Philip’s family disapproves. After Caroline reports all the conversations she had with Philip’s sister, Philip says, “What you have given me is a description, not an explanation.” Everyone knows what Philip means by this—in asking for an explanation, he wants to learn Caroline’s purposes. There is no purpose revealed in the laws of nature, and not knowing any other way of distinguishing description and explanation, Wittgenstein and my friend had concluded that these laws could not be explanations. Perhaps some of those who say that science describes but does not explain mean also to compare science unfavorably with theology, which they imagine to …