Red alert, day 74. Lockdown, day 64.
More of Warren Weaver, this time on scientific explanation. Many of us have thought the following, for example when reading bad wall texts in science museums, but Weaver, with the confidence of the mid-century master of the universe, was able to say it in print:
[A]s far as I can see[,] science has only two procedures of “explanation” and they are both, in any strict logical sense, frauds. One of these procedures consists of remarks which really say: “This phenomenon X which puzzles you should no longer do so; for it is closely like a phenomenon Y with which you have long been familiar.” The strange fact is that one need not really understand Y. He only needs to have been familiar with it for a long enough time so that he has the (fuzzy and unanalyzed) conviction that he understands it.
This is explanation by simile, and it is both strangely satisfying and practically useful. This is what happens when a scientist says, “Radio waves spread out, die off, are interfered with, like the expanding ripples when a stone is thrown into a pond.” This is what happens when a scientist says, “The electrons in an atom revolve around the nucleus as do the planets around the sun.”
These explanations by simile are not trivial. Not only do they bring the personal satisfaction of one who says, “You know, I didn’t understand that at all before, and now I do”’; they also furnish an important motivation within science as did, in the nineteenth century, the extensive simile comparing electrical quantities and actions with mechanical quantities and actions. But from any fundamental point of view, explanation of this variety, however comforting and useful it may be, is not really explanation. To say that the voltage that “causes” electricity to flow in a wire is like the pressure that causes water to flow in a pipe is very helpful and comforting to a person who is just establishing acquaintance with electricity, and who has for so long seen water flowing in a pipe that he thinks he understands why the pressure causes this; but it is certainly no ultimate explanation.
The second procedure of explanation is very different in character. It is exhibited in pure form in mathematics and theoretical physics. A statement is established by logical derivation from one or more previously established statements. They in turn have been established from a second prior set. One backs down a sort of logical staircase, the statements on each step having been proved by those on the next lower step. If one backs all the way down this stairway he eventually lands on a step which in our modern view does not bear the caption (which Euclid might have written there); “These statements are self-evidently true,” but rather bears the candid caption, “This is as far down as we presently go: the statements on this level are pure assumption.”
So this second kind of explanation, like the first, does not furnish any ultimate explanation. Both kinds, or mixtures of them, end either in the illusion of familiarity that makes one content to drop the effort or the bafflement of pure assumption.