October 6, 2018


Did Thomas Kuhn Kill Truth? : A debate on the nature of truth turns into a squabble over whether the father of the "paradigm shift" threw an ashtray at Errol Morris's head. (David Kordahl, Spring 2018, New Atlantis)

The preface to The Essential Tension (1977) -- Thomas Kuhn's first essay collection published post-Structure -- offers advice for students working to interpret primary sources in science. "When reading the works of an important thinker, look first for the apparent absurdities in the text and ask yourself how a sensible person could have written them." Kuhn continues, "When those passages make sense, then you may find that more central passages, ones you previously thought you understood, have changed their meaning."

Whatever your views on Kuhn, this seems like good advice. It's also the exact opposite of Errol Morris's approach to Kuhn in The Ashtray. Of course, if Morris directly experienced Kuhn as a violent maniac, this is understandable; few of us are eager to consider our abusers as important thinkers. On the other hand, with over a half-century of continued appeal, Kuhn must offer something beyond dogmatism and a halo of ash. So what, in his anger, has Morris left out?

Let's start with how well Kuhn was able to capture the way science is actually done. Unlike Kripke, Kuhn was one of us, a Ph.D. physicist whose firsthand knowledge of "normal science" allowed him to document scientific investigations in sensitive detail. To fellow scientists, many of Kuhn's claims seem less perverse than they are self-evident. When Kuhn discusses how paradigms define the way scientists approach the world, most of us will nod along, remembering the difficult years spent in reproducing classic experiments and solutions. The description of normal science as puzzle-solving within a paradigm certainly resonates with those of us actively searching for problems to tackle. By contrast, you'd be hard pressed to find a single working scientist who is out to discover necessary a posteriori truths.

Nevertheless, I suspect that beyond the fetching jargon and neat anecdotes, most scientists would in fact disagree with Kuhn's more radical claims. For instance, many physicists will agree that the world really is a certain way -- that, to the best of our knowledge, everything really is made of relativistic quantum fields. For such physicists, Einstein superseded Newton not for any sociological reason, but because he got closer to the truth.

Kuhn, however, was adamant that conflicting paradigms couldn't be compared so directly. To him, Einstein and Newton described genuinely different worlds, not simply better and worse renditions of the same one we all inhabit. The clearest articulation of Kuhn's final position can be found in The Road Since Structure (2000), a posthumous miscellany. While the presentation rehashes many of Kuhn's trademark concepts, it also acknowledges and addresses many of the usual concerns. Discussing incommensurability, Kuhn allows that we can always adopt the lexicon of a competing paradigm (listen up, Mr. Morris: this is how histories are written!), but he still maintains that we can only speak a single language at once, and hence still can't exactly translate old into new terms.

In the title essay -- a sketch for a future, never-completed book -- Kuhn calls his final view "a sort of post-Darwinian Kantianism." Kuhn's theory had always been recognized as "post-Darwinian" in the sense that he argued that the development of science, like biological evolution, is "driven from behind, not pulled from ahead." Scientific theories are accepted because of how well they solve the problems facing scientific communities at particular historical moments, rather than how well they correspond to the absolute truth about the world.

As he was working on his final book, Kuhn realized another sense in which biological evolution could provide a model for the development of science. The diversification of living things into different species, each with a specialized environmental niche, has an analogue in the diversification of science into narrowly specialized fields. And much as organisms from different species are unable to interbreed, the specialized lexicons of different scientific fields make it ever more challenging for different scientific specialists to understand one another.

The Kantian aspect of Kuhn's view has to do with Kant's notion that our experiences are inevitably filtered through certain categories of understanding, such as the concept of cause and effect. In Kuhn's words: "Like the Kantian categories, the lexicon" -- the way scientists talk about the world within a given paradigm -- "supplies preconditions of possible experience." In other words, the concepts we project on the world inextricably shape how we experience it, and scientists' paradigmatic lexicon shapes how they see the world.

Kuhn is sometimes described as a relativist, full stop; but this isn't quite right. Kuhn admits there's something objectively out there. But he qualifies that this thing-in-itself (as Kant put it) is "ineffable, undescribable, undiscussable." So what can we do?

Mostly, we talk, casting our nets over the dark sea. Once we settle on a stable way of talking, we can evaluate claims as objectively true or false. When a seemingly more useful way of talking arises, that's a scientific revolution. In this new way of talking we can once again evaluate claims as objectively true or false, even if, using the same words as before, claims that were true in the old way of talking might be false in the new way, and vice versa.

The issue here is not the denial of reality, but the denial of an absolutely preferred way of talking about it. Statements can be true or false, but not whole languages. As Kuhn puts it, "The ways of being-in-the-world which a lexicon provides are not candidates for true/false."

This is a "coherence theory" of truth, where truth applies not to the world but to statements about the world -- and even then only in a given language, only with a given use. This idea is perhaps disturbing, but it doesn't amount to what critics like Morris think. Morris charges Kuhn with claiming that the world is however we want it to be, but Kuhn in fact claims the opposite. In Kuhn's view, reality is out there, but it doesn't speak our language. It remains forever alien, non-linguistic, regardless of how well we seem to describe its various parts.

Posted by at October 6, 2018 4:07 AM