Messy Science

According to Kuhn, long periods of normal science are punctuated by occasional episodes of "revolutionary science."

There are obvious reasons for using the term, but there is an important reason Kuhn gives that is less obvious: According to the philosophies of science Kuhn was arguing against, there is a scientific method, that is, there are laws of scientific practice. Kuhn views the most important part of scientific revolutions as being that, as in the case of political revolutions, there are no laws. In particular, there are not even "canons of rationality."

It is characteristic of periods of scientific revolution that there are "rival paradigms."

Examples: Copernicus, Einstein, Watson, Crick, and Franklin.

But, and this is Kuhn's most interesting and controversial point, how do you decide which paradigm to ally yourself with? The standard answer would have been, the one with more verified (or less falsified) content. But that doesn't work, since the methods, standards, and problems of different paradigms are incommensurable. That is, there is no "common unit," no common language, in which the methods and results associated with different paradigms can be expressed and assessed.

Thus, there is just no way to rationally assess which paradigm is right, which one is better verified, in sum, there are no rules that help to decide which one to adopt. Kuhn says that switching paradigms is "like a religious conversion."

The view has, as we'll see, led to a sort of decades-long academic spring break for many who wanted nothing to do with the difficulties of science or the forbidding logical style of the philosophers of science. Because Kuhn has been used as an excuse for much lunacy, and because many philosophers of science have read Kuhn as endorsing lunatic views and hence set out to refute him, I'm going to now emphasize reasons like those Kuhn gives for thinking that science is still a legitimate and successful method of acquiring knowledge.

For a scientific theory to be successful in the short run, it just needs enough adherents. That is what makes Kuhn's picture of science seem to be one of an enterprise that is determined only by "political" considerations. However, in the medium term, it needs to produce a successful industry of boring science.

However, and this is a point that bothers many conservative philosophers of science, in the long term, the success of a paradigm over another is not a guarantee of its continued success. Atomism is the best example.

No grand paradigm is ever finally ruled out. No theory is ever eliminated except by the success of a rival. Scientific change sometimes means losing good old results.

Two additional points:

• No new paradigm "ever" absorbs the theories it supersedes, even as approximations. For example, Newtonian mechanics is not, despite what everyone says, approximately true for low speeds and masses according to relativity theory. We can, in this case and many others, recover equations and approximate laws of the same form as those of the old theory, but they concern different things, and there is no going back to the old picture of what the world is like.

• Rival paradigms will "always" be incompatible and incommensurable, according to Kuhn, because it is only a state of crisis in normal science that leads to a new paradigm, and the successes of a new paradigm therefore always concern "anomalies" in the old paradigm, problems the best practitioners of the old paradigm couldn't handle, and therefore problems that no one knows how to handle within the old paradigm: new, different, changed methods are required.

-- ShaughanLavine - 24 Mar 2009