Hume as Dualist and Anti-Dualist

Hume Studies Volume XXI, Number 1, April 1995, pp. 47-55 Hume as Dualist and Anti-Dualist PHILLIP D. CUMMINS Lome Falkenstein's recognition in "Hume and Reid on the Simplicity of the Soul" of the importance of the section of A Treatise of Human Nature entitled "Of the immateriality of the soul" is as praiseworthy as it is uncommon. His suggestion that Reid's intentionalist account of representation was motivated by his desire to save the doctrine of the immaterial self from Hume's demolition of it in "Of the immateriality of the soul," though not proven, is highly provocative. Although I am going to offer a somewhat different reading of "Of the immateriality of the soul" and thereby imply that Falkenstein did not sufficiently appreciate Hume's version of mental-physical dualism, I regard his paper as both informative and insightful and consider my proposed corrections fully compatible with most, if not all, of his substantive claims. Let me begin by contrasting two questions relating to mental-physical dualism. One is whether mental states or properties are irreducibly different from physical states or properties. Materialists generally acknowledge that there is an apparent, putative, or presumed difference between them, only to argue one way or another that the only genuine properties are material ones. Defenders of what I shall call Minimal Mental/Physical Dualism insist that the distinction between two fundamentally different kinds of properties remains at even the deepest levels of metaphysical analysis. One version of the second question is: Are there any immaterial beings? This question really concerns individual subjects, the items to which states or properties are assigned; it asks: do any individual subjects have only mental properties? To answer "yes" is to Phillip D. Cummins is at the Department of Philosophy, 269 English Philosophy Building, The University of Iowa, Iowa City, IA 52242-1408 USA. e-mail: phillip-cummins@uiowa.edu 48 Phillip D. Cummins hold what I shall call Strong Mental/Physical Dualism. Its opponents either answer "no" or take an agnostic stance. The two questions are not completely unrelated.1 As Descartes argued in the Sixth Meditation, an irreducible difference between mental and physical properties guarantees at least the metaphysical possibility of a disembodied mind.2 Despite this, an affirmative answer to the first question does not secure an affirmative answer to the second question. Minimal Mental/Physical Dualism does not entail Strong Mental/Physical Dualism. If it is possible for the same individual subject to have both mental and physical properties, it may be the case that whenever an individual subject has a mental property it also has a physical property.3 Consequently, an obvious strategy for establishing Strong Mental/ Physical Dualism is defending the impossibility of an individual subject's having both mental and physical properties, that is, arguing that the two kinds of properties are essentially incompatible with one another. Call this the Incompatible Properties Thesis. If it can be secured, to discover an individual with a mental property is virtually to discover an immaterial thing. Descartes utilized this strategy, also in the Sixth Meditation, where he wrote, The first observation I make at this point is that there is a great difference between the mind and the body, inasmuch as the body is by its very nature always divisible, while the mind is utterly indivisible. For when I consider the mind, or myself in so far as I am merely a thinking thing, I am unable to distinguish any parts within myself; I understand myself to be something quite single and complete. Although the whole mind seems to be united to the whole body, I recognize that if a foot or arm or any other part of the body is cut off, nothing has thereby been taken away from the mind. As for the faculties of willing, of understanding, of sensory perception and so on, these cannot be termed parts of the mind, since it is one and the same mind that wills, and understands and has sensory perceptions. By contrast, there is no corporeal or extended thing that I can think of which in my thought I cannot easily divide into parts; and this very fact makes me...