Reading Group: John Dupre's 'The Miracle of Monism'

Dupre's thesis is that philosophical naturalism, defined in part by being antisupernaturalism, in fact, when committed to monism, indulges in a species of the very supernaturalism it rejects. He defines monism as the physicalism that has replaced materialism. The latter is monism because it asserts roughly that anything that occupies the same physical space as us counts as being real, everything else being unreal. But, Dupre argues, theoretical physics, specifically quantum mechanics, has put pressure on materialism. This is because what quantum mechanics takes to be the fundamental physical entities apparently cannot be considered space occupiers at all. This leads us to physicalism, which is the doctrine that whatever our best physicists say are the fundamental constituents of reality provides the criterion for deciding whether or not an entity is to be included in a naturalistic ontology. The monism of physicalism is thus that only such entities are real (that there are only such entities). And Dupre thinks that this monism is in conflict with another central tenet of naturalism, empiricism, and so presumably, on this count physicalism is to be rejected. Monism is a myth that naturalism should not be committed to, and this leaves us with what Dupre calls 'pluralistic naturalism'. He diagnoses that the major appeal of monism despite its lack of empirical confirmation is another myth: that of the Unity of Science, and he devotes a large part of the paper to debunking this latter myth.

The link between unified science and monism is that science is taken to be a complete and exhaustive account of the world. There is an immediate difficulty over what such an account should include - is history, for example, to be included? If not, why not? Dupre leaves that question alone and settles instead for the strategy that if biology, chemistry and physics can't be unified there is no hope for any more complete unification. He then focuses on two ways in which science might be considered unified: unification of content, and unification of method.

The latter option is assessed in terms of Karl Popper's theory that science is unified by the method of falsifying hypotheses. Dupre marshals some arguments against this being the way science is done. This leads him to reject Popper's account. The evidence cited is quite convincing, but two points. First, Dupre argues that many other factors influence pursuance of scientific theories beyond falsification of hypotheses, such as checking for unknown variables and fitting one's findings with existing hypotheses. But it seems to me a sophisticated form of Popperism might still be able to show that all these methods are subsidiary to the method of falsifying hypotheses. Second, rejecting the idea that science is unified by a common method by examining Popper's theory alone leaves open the possibility of it being unified by other common methods.

We then move on to analysis of the hopes of unifying science around content. Dupre argues that reductions of more primitive scientific theories by their successor theories (his example is the replacement of the science of biological trait inheritance after the development of molecular genetics) do not preserve the subject matter of the more primitive theories. Thus there is no unity of content across the two theories. I'm not sure about this. Putnam has argued in several places that there is a way of understanding such different theories as referring to the same things. Any way, I don't find this convincing evidence to give up the idea of unity of content, although it does put pressure on that idea.

Another example Dupre cites is the reduction of mental content, such as beliefs, to brain states. He says that this is where the supernaturalism of monism is clearly in view, attributing to physical states magical meaning-bestowing properties for which there is no empirical evidence (he thinks the reduction is driven purely by a metaphysical commitment to monism). Again, I'm not sure about this, for just because our current reductive theories can't do justice to the phenomena being reduced isn't a reason to think no reduction at all is on the cards.

Dupre then suggests that such reduction would ultimately have to be to the fundamental entities of physics and that this leaves us with a world bereft of the familiar entities of common sense. On this ground such reduction is to be rejected. But the committed physicalist will simply shrug his shoulders and say all the worse for common sense.

Dupre then gets to what he takes to be the heart of the matter in terms of the connection between monism and the unity of science: the belief that science gives a complete account of nature. He says the belief that such a complete account must in principle exist is a supernatural belief not grounded in empirical science. He then goes on to argue that when we look at actual scientific practice, there is no reason to think that laws identified in one context will be capable of generalisation across diverse physical systems.

There then follows a discussion of the epistemic function of the myth of the unity of science: that once a practice gets the honorific title 'science' it joins an exclusive club that bestows epistemic warrant upon membership.

Dupre concludes with the idea that monism as a commitment to there being nothing beyond the physical realm is ok, because good empirical evidence to support it. But a form of monism such as physicalism goes beyond this, holding that everything must be explainable only in terms of the behaviour of the properties of the physical stuff physicists take to be the fundamental constituents of reality. This kind of monism is a myth and we should be pluralist naturalists allowing anyone in to the explanatory project who doesn't transgress the first kind of monism.

Pluralistic naturalism is obviously quite attractive but here are a couple of problems with it. Without the metaphysical commitment of physicalism, taking empirical science to be the arbiter of good epistemic practice becomes almost a matter of temperament. Physicalism underwrites the status of (some) empirical science as such an arbiter, because it tells us that this science is committed to investigation of reality in the only terms that are apt. Lose this underwriting function of physicalism and appealing to the experimental success of empirical science as evidence for adopting the weaker monism of anti-supernaturalism begins to look circular.

Even if we adopt anti-supernaturalism willingly, allowing so-called 'non-scientific' investigation into the fold might lead to rejections of our best science on various a priori grounds (one can be both an a priorist about scientific practice and an antisupernaturalist). Is this something that can seriously be called naturalism? Perhaps Dupre would here lean on his empiricism. This brings me to my final comment.

Dupre appeals repeatedly to empiricism as a central tenet of all naturalism. It is not really clear what is meant by this. It at least seems to mean prioritising empirical confirmation over other methods employed in doing science. But is this justified (is it more faithfully naturalistic)? Some might argue that given the importance of mathematics for understanding the natural world the theoretical virtues of this discipline trump the theoretical virtues of empirical confirmation. Then one might have a reason for supposing that naturalists should be committed to the idea that a complete unified explanation of reality is both possible and the asymptotic aim of inquiry. For mathematics, I presume, does not tolerate incommensurate theories.