Physics, Mathematics and Skepticism

Stathis Psillos reviews Hilary Putnam's Philosophy in an Age of Science: Physics, Mathematics and Skepticism, in Notre Dame Philosophical Reviews:

In his address to the Fourth International Congress of Philosophy held at Bologna in 1911, Henri Bergson noted that "a philosopher worthy of the name has never said more than a single thing: and even then it is something he has tried to say, rather than actually said". This single thing, he added, being "a thought which brings something new into the world", "is of course obliged to manifest itself through the ready-made ideas it comes across and draws into its movement".

What then is Hilary Putnam's -- who has been one of the major philosophers of the twentieth century -- 'single thought' and what is the 'something new' it brings into the world? Well, it's not quite a single thought but it can be captured, I think, by the following: there is something about science which is of incomparable cognitive significance and there is something about human beings which is of incomparable moral significance. The 'something new' then that Putnam's outstanding philosophical endeavour brings to the world is the fusion of the scientific image of the world with a moral image of human beings. This is the thread that runs through the papers that compose Putnam's latest collection: Philosophy in an Age of Science: Physics, Mathematics and Skepticism. As Putnam puts it: "My efforts in philosophy have always been intended to provide intellectual and moral support to those who have realistic sensibilities in science and 'cognitivist' sensibilities in ethics" (93). In this review, I will concentrate my attention to the first two parts of the book, which discuss issues in the philosophy of science and mathematics.

Putnam makes a concerted effort to dispel a popular misconception that when he criticized metaphysical realism he had also abandoned scientific realism too (see especially p. 92). Actually, those who had tried to follow his work on scientific realism closely would know that he never put scientific realism on halt. In the midst of his conversion to internal or pragmatic realism, as Putnam tended to call his verificationist turn, he published a significant (but perhaps not widely read) piece in which he did endorse scientific realism, suitably dissociated from both materialism and metaphysical realism (cf. 1982). Back in the early 1980s, scientific realism was still what it was taken to be by the Putnam of 1960s and 1970s -- the ferocious critic of instrumentalism, operationalism, fictionalism and other forms of scientific anti-realism. Scientific realism was still taken to involve commitment to the following theses: theoretical entities have irreducible existence (they exist in the very same sense in which ordinary middle-sized objects exist and are irreducible to either them or complexes of sensations); theoretical terms featuring in distinct theories can and do refer to the same entities (hence, there is referential continuity in theory-change); there is convergence in the scientific image of the world; and scientific statements can be (and are) true. Yet, the verificationist Putnam of the early 1980s took truth to be "correct assertibility in the language we use" (1982, 197). So scientific realism was retained but dressed up in a verificationist garment.