Incommensurability: Mostly Harmless

The limits of language mean the limits of my world, so tweeted Ludwig Wittgenstein before Twitter. One might want to regard that as being puzzling given our every day notions of causality. Thomas Kuhn in his The Structure of Scientific Revolutions stated of his much discussed incommensurability thesis, “these examples point to the third and most fundamental aspect of the incommensurability of competing paradigms. In a sense that I am unable to explicate further, the proponents of competing paradigms practice their trades in different worlds.”

The connection to Wittgenstein that can be so drawn is an important one.

In a previous post I had written a review of three books that I had recently read. One of these was Monk’s biography of Wittgenstein. The part on Wittgenstein fits oddly, and I have since thought that section could have been more nuanced. Anyway, such is life for we live and learn. One thing that I wished to discuss was the connection between Wittgenstein’s highly valuable use theory of meaning, a value derived from its explicit rejection of an externalist semantics, and Kuhn’s incommensurability thesis.

It seems to me Kuhn’s thesis is pretty much trivial, it being a restatement of Wittgenstein’s use theory of meaning made applicable to the specific context of science. Furthermore, the debate on epistemic relativism that the Kuhn thesis continues to engender comes across as much ado about nothing when viewed in Wittgensteinian vein. Wittgenstein’s use theory arises from his latter work especially The Philosophical Investigations. Here Wittgenstein’s states, “For a large class of cases of the employment of the word ‘meaning’—though not for all—this word can be explained in this way: the meaning of a word is its use in the language.” Note that it is use “in the language” that Wittgenstein speaks of. If you take a scientific theory to be a language then concepts of importance to the theory, let’s say in physics such as causation, mass, energy, space, time and so on derive their meaning through use in the language, that is via their use in theory. Science is one of Wittgenstein’s large cases.

Let us take causation or causality. In Aristotelian theory, within the language that constitutes the corpus of Aristotle’s thought, the concept cause does not have the same use, so the same meaning, as that in Newtonian theory.  Aristotle’s use of causality was essentialist and teleological. In Newtonian theory cause and effect arise through external forces acting upon bodies.  Newton’s laws of motion make use of just such a concept of causality. The modern picture, to the extent that causality is retained (in relativity at least), is certainly not Newton’s but for simplicity of argument allow us to stick to this distinction.

Incommensurability means that Aristotle’s and Newton’s conception of causality differ but nonetheless no one conception possesses any more sense or meaning than the other. Aristotle’s conception of causality is not any more nonsensical than Newton’s and Newton’s is not any more meaningful than Aristotle’s. This is because meaning comes through use within a language, and there exists no transcendental language to which we might appeal to declare one conception more meaningful than another.

That to me seems like a straightforward, indeed trivial, extension of Wittgenstein’s theory of meaning to the matter of science. There really shouldn’t be anything here for us to get excited about. But we do get excited because many draw relativist conclusions from this, even though they cannot follow. Some draw that relativism favourably, so the strong programme in the sociology of science draws relativist conclusions from incommensurability and her exponents quite enjoy it. The feeling is one of chic radicalism and naughty subversion. Others, who seek to defend the cognitive or epistemic claims of science, also draw relativist conclusions but are outraged by this fearing for the future of western civilisation no less. There must be something amiss with Kuhn, the defenders of the honour of science valiantly declare. Indeed, their must be something not right about the very idea of a conceptual scheme.

Should the causality of Aristotle be no less meaningful than the causality of Newton then Newtonian science has no superior claim to the truth. Heaven forbid, should the causation of astrology be no less meaningful than the causation of Einstein. Surely in such a situation the epistemic warrant of science would be torn asunder. But it is not hard to see that such is not so. Recall Wittgenstein’s use theory of meaning is an internalist semantics. It is not an externalist or referential theory of meaning. The charge of relativism sticks only to the extent that we allow ourselves to succumb to one of the key dogmas of empiricist philosophy, namely meaning is a species of reference. Should that be the case then the causality of astrology has no less referential warrant than the causality of Einstein. But an internalist is not worried by this, and she happily finds better things to think about than incommensurability and the epistemic foundations of science. Life is too short to worry about pseudo problems, and an examined life is not a life to be devoted to such pursuits. We might get ourselves from Kuhn semantic relativism but certainly not epistemic relativism.

There is more than a pinch of irony here. Apart from demonstrating the hold that referential understandings of meaning continue to have, they show that both supporters and critics of the strong programme, in so far both hold incommensurability leads to epistemic relativity, share a strong commitment to empiricist dogma given both positions are underpinned by a referential semantics.