David Bentley Hart's Arguments Against Substance Dualism

I've started reading David Bentley Hart's latest book, All Things Are Full of Gods, a 500 page Platonic dialogue about the philosophy of mind. I'll save general impressions for another post, but wanted to note a particularly interesting (to me) series of arguments he makes (through his mouthpiece, the goddess Psyche) fairly early on against dualism.

What makes the arguments of interest to me is that I once considered myself a substance dualist, and I still find myself instinctively thinking in Cartesian ways. Cartesian forms of dualism are very common still, if not a majority position, among Christian philosophers in the analytic tradition. Since Hart's earlier book, The Experience of God, helped cure me of some of the anthropomorphisms that my upbringing in analytic philosophy of religion made instinctive, I'm hopeful this book can begin to do something similar for my now-instinctive Cartesianisms.

An antique photograph of Psyche

Before getting into the arguments, two things are worth noting. First, the arguments are against a particularly strong version of Cartesian dualism, in which mind and body are conceived of as distinct substances which can exist independently and must be characterized in intrinsically non-overlapping and opposing ways. Thus, for Descartes, a mind is necessarily an non-extended and thinking thing, whereas body is necessarily extended and non-thinking. This is important to note because Hart's view is dualistic in a much weaker sense--he is happy to distinguish between mind and matter, for example.

Second, he notes that his problem with dualism is not the interaction problem as it is usually presented. He rejects that version of the interaction problem because it tends to presuppose that all causes are mechanical causes, that the mind could only ever cause anything to happen by collision or some other exchange of physical force, which of course a wholly immaterial mind is incapable of. But this is a prejudicial and atrophied understanding of causation. Still, the idea of 'interaction' between two things defined as intrinsically metaphysically distinct does seem to be foundational for his worries about dualism (of the modern sort).

He presents three arguments explaining his rejection of dualism as usually conceived:

(1) If mind and matter are conceived of as totally and irreconcilably distinct, then any dualism is necessarily mysterian and repugnant to reason.

For one thing, I object in principle to all dualistic answers to any question. Every duality within a single reality must be resoluble to a more basic unity, a more original shared principle, or it remains a mystery. Simply to juxtapose two disparate substances and then declare that, just by being associated with one another, they’ve been reconciled is to trade in paradox. If body and mind are distinct and yet interact, then there’s some ground of commonality that they share, more basic and encompassing than the difference between them.... (p.46)

No, in the end, a dualism can never be more than a provisional answer to any question; for two qualitatively different relata to be reconciled, there must be some broader, simpler, more encompassing unity in which they participate, some more basic ontological ground, a shared medium underlying both and repugnant to neither (p.48).

(2) If mind and matter are really wholly distinct and incommensurable, then it's not clear how even God could reconcile them (*contra* Malebranche). How could completely irreconcilable principles flow from the same simple God? How could even he do the apparently logically impossible act of connecting substances that have no logical connection?

So I have to believe that, to whatever degree body and soul differ from one another, they’re also always already reconciled to one another at a deeper level where they operate as a single agency. Anyway, the “will of God” isn’t a real answer to anything, since “will” is neither a logical nor an ontological principle. After all, not even God could reconcile intrinsically irreconcilable substances, any more than God could create a square circle. Omnipotence extends as far as the very ends of all that’s possible; but it doesn’t extend to the logically impossible. If the world of God’s creation contains both mind and matter as fully distinct realities—which, again, I don’t really grant— then it seems strange to suggest that they’re mutually inimical principles; how could they both proceed from the one divine nature, then? (p.47)

(3) Most problematically, dualism unmakes the human being, who is clearly both mind and body. I am not an irreconcilable mishmash of different substances, I am this being which with *my physical hand* plucks a flower because of my *mental appreciation* of its beauty. If mind and body are totally distinct substances, then *I* as I typically conceive of myself do not exist.

If I consist in two separate causal streams that can never really interact, then I, as an embodied soul or an ensouled body, do not actually exist; and I have the impertinence to believe that I do. When I pluck a rose, it’s my hand that does the work; when a thought passes through my mind, it’s that thought itself that causes certain regions of my brain to flicker and flare. I’m not a fiction composed from two separate histories, only apparently combined with one another as a kind of divine stage effect. (p.47)

He begins to hint here at his positive view, already suggested to some degree by his negative arguments. The materialist, at least, tries to reconcile mind and body by grounding both in a more fundamental idea of material substance. Hart argues this approach is bound to fail. So he thinks the proper approach must be a type of idealism, one which sees both mind and body as distinct expressions of a more fundamental idea of mind/soul/spirit. While there is some sort of conceptual dualism, here, there is "not an ultimate duality, no. Chiefly I believe that ‘soul’ is simply the rational life principle that expresses itself in the whole organism, body and mind alike" (p. 48).

Note that this requires a broader conception of mind/soul than the individual thinking ego of Descartes (what he calls the psychologistic fallacy). I'll probably address that in another post.