Locus of mind-body interaction

Ladevel asked:

‘In resolving the problem of interaction, Epiphenomenalism shows itself to be a stronger theory than Cartesian Substance Dualism.’ How do I offer a critical analysis and evaluate this in a high school essay for philosophy? I need a solid argument that encompasses objections, weaknesses etc but also arrives at a solid, well justified conclusion.

Answer by Gershon Velvel

Don’t you love it when philosophy instructors tell you in advance what conclusion you should come to in your essay? What if you decided, after looking at the arguments for and against, that substance dualism is the stronger theory? Would you automatically get a D?

It is at least arguable that epiphenomenalism as a solution to the mind-body problem — the theory according to which the brain ’emits’ consciousness in a similar way to a factory emitting smoke — is a feeble attempt to account for our seeming awareness of something ‘inner’. When an epiphenomenalist writes, ‘I believe in epiphenomenalism,’ the causal chain that led to those words appearing on paper or on a computer monitor is physical all the way. The ‘inner’ never came into it, because according to epiphenomenalism, the ‘inner’ is merely an inert by-product of physical processes.

On this count, at least, substance dualism is a clear winner. As Descartes observes in his own case, I am aware of something — my thinking, my experiencing — that could exist even if the physical world did not. When the dualist writes, ‘I believe in dualism,’ the causal chain goes from the actions of ‘mental substance’ — my Cartesian ‘soul’ — to changes in physical substance.

But how could such action, or interaction, possibly take place? Where is the locus of mind-body interaction? This is a point on which Descartes was pressed by several critics, including Pierre Gassendi and Princess Elisabeth. That’s only part of the problem, because the idea of physical changes being brought about by something outside the physical realm clashes with the Law of Conservation of Energy.

The latter, apparently, wasn’t an issue for Descartes because his physics was non-Newtonian. In Cartesian physics, no physical force is required to change the direction of motion of the ‘animal spirits’. If that seems crazy to us today, remember that for Descartes, mental substance and physical substance are maintained in existence by God’s continuous action. The ‘laws’ of physics are based purely on the geometry of extended bodies. The only violations that these laws forbid are geometrical violations (for example, two bodies existing in the same place at the same time). The rest is up to God, who by decree has endowed mental substance with the power to affect, and be effected by the animal spirits.

Well, of course, we don’t believe that now. Our physics is Newtonian (at a first approximation), not Cartesian. But, still, given indeterminacy at the quantum level it not inconceivable that, God or not, mental substance might still have the power to alter local probabilities without violating any laws.

For example, suppose I discover to my extreme surprise that whenever I think of a proposition from Wittgenstein’s Tractatus, say, ‘The world is all that is the case,’ the words appear on the fluorescent tube light in my kitchen. The energy emitted by the fluorescent tube remains the same, all that is altered is the pattern of ‘random’ photon emission. That would be very spooky, and one would want to know the explanation. But one candidate explanation which can’t be logically ruled out is that I did it, myself, by a form of telekinesis. Maybe with God’s help. But the laws of nature remain more or less intact. (No mentally knocking vases off mantelpieces, for example.)

The locus of interaction at first sight seems a more intractable problem. Descartes said that this occurs in the pineal gland located in the brain. At what location, exactly? You might be thinking that, as a ‘unextended substance’, the soul could only occupy a geometrical point. But this is wrong. The soul is not in space, because it does not possess any of the essential attributes of extension. It acts  at a specific place, which could be the whole body, or the brain, or the pineal gland — whichever hypothesis seems the most plausible.

Our naive view of causation requires contiguity of cause and effect. Gravity, which at first sight seems to be an example of action at a distance, in fact (according to physics) involves a ‘gravitational field’. Our experience of causes and effects is an acceptable starting point for defining ‘causation’, but it is only a starting point. Descartes believed that he had given a powerful argument against the idea that all causation involves physical pushes and pulls.

Is Cartesian substance dualism a ‘strong’ theory? That all depends on how favourable you are to the alternative view to either substance dualism or epiphenomenalism: namely physical monism. There’s no question that if you give up physicalism, there’s a price to pay, but the question remains open. In academic philosophy, doubts about physicalism are on the rise, though relatively few philosophers would be prepared to go the whole hog and defend Descartes, as I would.

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