Lok-Chi Chan

Throughout history, numerous thinkers have claimed that monism – in the form of priority monism, existence monism, monotheistic monism, or versions that posit an extra-cosmic ultimate being – theoretically surpasses pluralism, above all by positing a unified universe. This view re-emerges in recent metaphysics through what I call cosmological arguments from parsimony (CAPs) and cosmological arguments from relations (CARs). According to CAPs, monism is more ontologically parsimonious than pluralism because it posits only one fundamental entity. According to CARs, the single fundamental object in monism serves as a required metaphysical explanans for how things in the universe can form certain relations with each other. I argue that this longstanding tradition of arguments spanning Neoplatonism, early and late modern philosophy, analytic philosophy, and even some Eastern traditions fails: monistic frameworks largely fail to reduce the universe’s ontological complexity as alleged, and the remaining ones fail to show any theoretical advantage over pluralism for related reasons. Drawing on the broader materialist tradition, the article also offers a positive case for several theoretical merits of pluralism and ends with a takeaway concerning how best to inquire into the universe’s unity.

Russellian monism—an influential doctrine proposed by Russell (The analysis of matter, Routledge, London, 1927/1992)—is roughly the view that physics can only ever tell us about the causal, dispositional, and structural properties of physical entities and not their categorical (or intrinsic) properties, whereas our qualia are constituted by those categorical properties. In this paper, I will discuss the relation between Russellian monism and a seminal paradox facing epiphenomenalism, the paradox of phenomenal judgment: if epiphenomenalism is true—qualia are causally inefficacious—then any judgment concerning qualia, including epiphenomenalism itself, cannot be caused by qualia. For many writers, including Hawthorne (Philos Perspect 15:361–378, 2001), Smart (J Conscious Stud 11(2):41–50, 2004), and Braddon-Mitchell and Jackson (The philosophy of mind and cognition, Blackwell, Malden, 2007), Russellian monism faces the same paradox as epiphenomenalism does. I will assess Chalmers’s (The conscious mind: in search of a fundamental theory. Oxford University Press, New York, 1996) and Seager’s (in: Beckermann A, McLaughlin BP (eds) The Oxford handbook of philosophy of mind. Oxford University Press, New York, 2009) defences of Russellian monism against the paradox, and will put forward a novel argument against those defences.

Russellian monism – an influential doctrine proposed by Russell (1927/1992) – is roughly the view that the natural sciences can only ever tell us about the causal, dispositional, and structural properties of physical entities and not about their categorical properties, and, moreover, that our qualia are constituted by categorical properties. Recently, Stoljar (2001a, 2001b), Strawson (2008), Montero (2010, 2015), Alter and Nagasawa (2012), and Chalmers (2015) have attempted to develop this doctrine into a version of physicalism. Russellian monism faces the so-called combination problem, according to which it is difficult to see how categorical properties could collectively constitute qualia. In this paper, I suggest that there is an insufficiently discussed aspect of the combination problem which I call the difference-maker problem. Taking the difference-maker problem into account, I argue that the combination problem – whether or not it can be solved – results in a dilemma for the project of developing Russellian physicalism. That is, Russellian monism is either physicalistically unacceptable or it is implausible; hence, Russellian monism and physicalism are incompatible.