Abstract

In the years spanning the first half of the 20th century Bertrand Russell wavered between two incompatible accounts of physical reality. On one account, physical objects were taken to be logical constructs of phenomenal entities, the immediate data of sense experience. Such a view roughly fits the familiar characterization of being a combination of “Hume plus mathematical logic.” This type of phenomenalism, in the empiricist tradition, contrasted starkly with a variant of scientific realism, including a realistic account of causal connections as relations between universals, that Russell developed between 1912 and 1927, and which was derived from Kant’s distinction between a noumenal and a phenomenal world. My concern in this paper is with the viability of the unique form of scientific realism Russell developed, the role of universals and causal explanation in it, and criticisms that have been directed at it. I will argue that an early refutation of Russell’s realism by the mathematician M. Newman and a recent revival of that refutation by W. Demopoulos and M. Friedman ignore the critical role universals play in Russell’s scientific realism and hence fail to refute his view. I will also briefly consider a recent “anti-realist” argument that repeats Newman’s mistake: interpreting predicates in terms of extensions and not as referring to universal properties and relations.