Metaphysical Naturalism and the Ignorance of Categorical Properties

Abstract

The purpose of this dissertation is to investigate the connections between metaphysical naturalism and the categorical ignorance thesis – offered by Rae Langton (1998), David Lewis (2009), Frank Jackson (1998), and Simon Blackburn (1990) – and determine whether the latter will challenge the former. According to metaphysical naturalism, the actual world contains only metaphysically natural things. According to the categorical ignorance thesis, all we can know about things are their dispositional properties, but the categorical properties that bear these properties remain in principle unknowable. In this dissertation, I will determine whether the ignorance of categorical properties – as Rae Langton (1998), David Braddon-Mitchell and Frank Jackson (2007), John Foster (1993) and Alyssa Ney (2007) argue (or worry about) – is consistent with metaphysical naturalism (or physicalism), and whether it will lead to a scepticism about the metaphysical naturalness of categorical properties, which will, in turn, significantly decrease the probability that metaphysical naturalism is true. Being attracted to metaphysical naturalism, the categorical ignorance thesis, and also the philosophical position that the two theses are consistent, I will argue that the answer to the former question is yes, and that the answer to the latter question is no. Russellian Monism, an influential doctrine in philosophy of mind that is relevant to the topic, will also be considered. According to the doctrine, our first-person experiences are constituted by their categorical bases in some manner that is not (solely) via the dispositions borne by these bases. Some philosophers, such as Bertrand Russell (1992/1927a, 1927b), thus consider categorical properties to be knowable through our acquaintance with those experiences. On the other side, some philosophers, such as Daniel Stoljar (2001a, 2001b, 2006), David Chalmers (1996), and Galen Strawson (2013), argue that Russellian Monism is compatible with metaphysical naturalism (or physicalism). In this dissertation, I will determine whether the acquaintance view put forward by some Russellian Monists, understood as an objection to the categorical ignorance thesis, is true and whether it is compatible with metaphysical naturalism; I will argue that the answers to both questions are no.