Polanyi vs. Kuhn

As I am reading Polanyi's Personal Knowledge I can't keep thoughts of Thomas Kuhn's Structure of Scientific Revolutions far from my mind. So much of what Polanyi is saying is similar to what Kuhn says, although I believe they differ on certain key points. Kuhn apparently claimed that his work did not take anything from Polanyi's, but that is hard for me to believe given the fact that several of Kuhn's key theses are stated (in some form) in Polanyi's book, which was published well before Structure.

A member of my discussion group sent me a link to an article in the Polanyi Society's periodical by Martin Moleski on "Polanyi vs. Kuhn." I found the article very helpful. The article is available here: Polanyi vs. Kuhn. The rest of this post consists of my thoughts on Moleski's article.

I found Moleski's article very helpful in disentangling some initial impressions I had about the similarities between Polanyi and Kuhn. I have always been very troubled by Kuhn's concept of incommensurability. I have heard that Kuhn developed many of his ideas about scientific theory change while writing his book on the Copernican Revolution. But the more I have studied the Copernican Revolution the more I have been bothered by Kuhn's notion that nothing can mediate the two sides of the dispute in a "paradigm shift." I would seem that Polanyi may provide a middle ground between purely empiricist claims that sense experience is always the final arbiter in any scientific dispute (a claim that simply doesn't fit with most of the history of science) and Kuhn's relativist position. I am convinced that there are ways to arbitrate disputes over scientific theories, but that the principles that can be used to arbitrate these disputes are metaphysical rather than purely empirical. One way to say this is that scientists have a commitment to making their theories match the empirical data, but they also judge scientific theories according to a variety of what might be termed "aesthetic" criteria. The extent to which a scientific theory fits a given piece of empirical data may be (but is not always) unproblematic, but the choice of which aesthetic criteria are applicable can lead to major disagreements about which theory is superior.

Let me draw an example from the Copernican Revolution (since I have been studying this subject for 6 months now, and since both Polanyi and Kuhn make use of this example). In selecting between the Ptolemaic and Copernican systems, astronomers certainly considered how each theory matched to the observed data. But both theories were equally good (or bad) in this regard. It turned out Copernicus' theory was a bit easier to use in some ways, so many astronomers adopted his system for their calculations - but almost none of these seem to have believed in the reality (or truth, if you will) of the Copernican system. Some took what might be described as a positivist approach in which they viewed astronomical theories as ways of generating predictions for planetary positions, and nothing more. But some saw astronomical theories as representations of reality and these almost invariable committed themselves to the Ptolemaic view. Why? It seems to me it was because of the aesthetic criteria they chose to apply. Specifically they wanted an astronomical theory that fit with common sense observations (we don't FEEL the Earth moving), with the prevailing Aristotelian physics and cosmology, and that didn't contradict Holy Scripture. In favor of the Copernican system one could bring to bear a different set of aesthetic criteria, criteria that focus on the coherence and order of the theoretical system and the fact that only with the Copernican system could the distances to the planets be determined from observation. These were the features that ultimately convinced a few later astronomers like Kepler and Galileo to adopt the Copernican view.

It might seem that this would lead us to Kuhn's relativistic impasse: how are we to judge which set of aesthetic criteria is best? Clearly not by appeal to empirical data. Any principles which help us to select the best set of aesthetic criteria must be metaphysical. I take Kuhn to say that the selection of aesthetic criteria is subjective and is mostly a matter of conforming to tradition. And yet, there is no doubt that aesthetic criteria, like scientific theories, DO change. The Copernican Revolution occurred not because the Copernican theory finally proved itself to be empirically superior to the Ptolemaic theory (that did eventually happen after Kepler radically reinvented the "Copernican" theory - but Kepler had to first accept the Copernican viewpoint before he could transform it into an empirically superior theory). My sense is that the Revolution occurred because of changes in the aesthetic criteria used to judge scientific theories. Kepler, for example, saw coherence and order as the most critical criterion for judging a theory. He was awed by the intellectual beauty of the Copernican theory, in contrast to what he saw as the ugliness of the Ptolemaic theory. Galileo, on the other hand, came to question Aristotle's physics (and cosmology) as well as the "common sense" views about motion. Both men abandoned some of the aesthetic criteria that had been used against Copernicus and adopted new criteria that came down in favor of the heliostatic theory. They both also tried to find a middle ground on the issue of Scripture, claiming that the Bible is not a science text but a revelation about God that is given from a "human perspective". Neither was very successful in this venture: Kepler's views on interpreting Scripture were basically ignored (like much of his astronomy, for a while) and it was primarily Galileo's attempts at Scriptural interpretation that got him in trouble with the Inquisition.

So how were these men able to break from 1400 years of tradition? What motivated their change in aesthetic criteria? I am becoming increasingly convinced that it was their commitment to realism. Both men were trying to get at the truth of the world, rather than an economical description of it. They found the disjunction between astronomy and physics unacceptable. A TRUE theory should account for the motion of the heavens AND the motion of objects on Earth. They sought to unify physics and astronomy because they were convinced that only such a unification could bring them closer to the truth. They went about this unification in different ways, and both made mistakes (from our modern point of view). Kepler retained Aristotle's ideas about motion on the Earth and tried to apply them to the heavenly bodies. Galileo dismantled Aristotle's views on Earthly motions but his replacement was greatly influenced by Aristotle's views about the "natural" circular motions of the heavenly bodies. But both men came to question the traditional aesthetic criteria for judging astronomical theories and began to apply radically new criteria in an effort to find the truth (or so I think).

This is, according to Martin Moleski, the dividing line between Kuhn and Polanyi. Kuhn refuses to commit to any ideal of truth or reality. Thus he remains mired in relativism and incommensurability. Polanyi is willing to take the bold step of proclaiming that science seeks the truth (not that it can necessarily get there, but it at least SEEKS to get there). This commitment to realism provides, I believe, a way out of relativism and incommensurability. It seems to be the case that a realist viewpoint drives us toward adopting certain criteria for scientific theories while leading us to reject others. Polanyi talks about some of these criteria that lend themselves to a realist perspective: "man's delight in abstract theory" and "theories may be constructed without regard to one's normal mode of experience". I look forward to reading more about his criteria for objectivity, which I take to be aesthetic criteria for judging scientific theories. My hope is that I will find Polanyi's approach much less troubling than Kuhn's.