Ad 1. There are certain data that no one will dispute, whether materialist, dualist, or idealist. Among these data are the various correlations to which Malcolm is referring: stimulate this portion of the visual cortex in such and such a way and the subject experiences phenomenal blue, etc. Intelligent dualists have always been aware of such basic facts as that drinking alcohol alters the quality of one’s qualia, that a blow to the head can cause unconsciousness, and the like. It is important to realize that dualists are not in the business of denying obvious facts. The questions are not about the gross facts, but about their interpretation, about what they mean and what they entail. Hence dualists cannot be refuted by citing any obvious facts. Indeed, if dualism could be refuted by citing empirical facts, it would not be a philosophical thesis at all.

I stress this, because many don’t understand it. They think that substance dualists deny facts that are well-known or scientifically established. One commenter, for example, compared substance dualists to flat-earthers — which of course shows total misunderstanding.

“Why is this the case, if our minds aren’t simply something the brain is doing?” Because it could be the case even if our minds are not simply something the brain is doing. If substance dualism is true, then the mind is a substance. But note the following definition:,

D1. X is a substance =df X is metaphysically capable of independent existence.

(D1) lays down what is meant by ‘substance’ in discussions about substance dualism in the philosophy of mind. That and that alone is what is meant by the term.

Note also that ‘substance’ has a half-dozen or so meanings, and that in this context, ‘substance’ does not mean stuff. Thus the dualist cannot be blown out of the water by some such cheap shot as saying that he is committed to something self-contradictory like immaterial matter. (Not that Malcolm would reach for such a cheap shot.)

So for the dualist, the mind can exist without being embodied. But my mind, with which I am rather well acquainted, is an embodied mind. It is embodied as a matter of contingent fact, though not as a matter of metaphysical necessity. So it is not surprising that what goes on in my mind affects and is affected by what goes on in my brain and central nervous system. It is not surprising that the states of an embodied mind will be affected by alcohol in the bloodstream. In general, it is not suprising that (some) changes in the brain will bring about changes in the mind.

Since the facts that Malcolm adduces can be explained both materialistically and dualistically,, his adducing of said facts does not support materialism over dualism. Since the facts are consistent with both schemes, they do not entail either scheme.

So what Malcolm says in #1 is not a good reason to reject dualism. Of course, what I said in rebuttal does not provide a good positive reason to accept dualism over materialism. What I have done is merely remove a threat to the rationality of dualist belief.

Now what exactly is the objection? It seems to be this. If mind and body belong to mutually irreducible ontological categories, and yet minds and bodies interact causally, then this violates conservation principles. For example, if my intention to paint the bathroom is an irreducibly mental state that causes the states of the brain that control the motions of my limbs, then there is presumably a transfer of energy into what is supposed to be a closed physical system in violation of the principle of conservation of energy.

The trouble with this objection is that it blatantly begs the question against the dualist by presupposing a transfer theory of causation that makes dualist interaction impossible from the outset. Obviously, there could be a violation of conservation principles only if causation is being viewed as the transfer of some physical magnitude.

But it is not at all clear that causation involves such transfer even among physical causes and physical effects. There are several theories of causation. Many empirically-minded philosophers, following in the footsteps of Hume, adopt some version of the Regularity Theory, the gist of which is this:

Event-token e (directly) causes event-token f =df (i) e and f are spatiotemporally contiguous; (ii) e occurs earlier than f; (iii) e and f are subsumed under event-types E and F that are related by the de facto generalization that all events of type E are followed by events of type F.

On this theory, what distinguishes a causal event-sequence from a non-causal one is nothing more than the former’s instantiation of a regularity. Causation ‘in the objects’ is just regular succession, just one event after another. Accordingly, nothing gets transferred or transmitted from cause to effect. On this theory of causation, the above objection to mental-physical and physical-mental causation collapses.

Of course, there are powerful objections to the Regularity Theory. But there are other theories on which mental-physical and physical-mental causation are unproblematic. On a counterfactual theory,

e causes f =df if e had not occurred, f would not have occurred.

Here too, there is no need for any transfer of a physical magnitude and hence no threat to conservation principles.

But suppose that, in the physical world, causation is a process that involves physical contact and the transfer of energy, momentum, or whatever from the cause to the effect. If causation is such a physical process, then it will be a spatiotemporally continuous one and one can attempt to trace the mechanism whereby the cause brings about the effect. But mental-physical causation is direct: there is no intervening mechanism. To demand that there must be one in the mental-physical case as in the physical-physical case is just to rule out by fiat mental-physical causation.

 Why then should there be any problem with a mental state directly causing a physical state? Once one has a specification of the relevant causal properties and the covering law, what more could one ask for?

In sum, the above objection unwarrantedly assumes that causation must in every case involve transfer of some physical magnitude. But it may be that causation never involves such transfer, or it may be that it involves such transfer only in the physical-physical cases. To make the above objection stick, therefore, one must do a lot of work; one must articulate a tenable transfer theory of causation. What one cannot do is simply repeat the canard given at the outset.

This is an amazing passage in that it compares the views of distinguished dualist philosophers such as Richard Swinburne to the views of astrologers, alchemists, and flat-earthers. It would be very interesting to hear precisely how the views of Swinburne et al. are in “defiance of modern science” — assuming one doesn’t confuse science with scientism. But let’s look at what Dennett has to say in his more substantial (511 page!) Consciousness Explained (1991).

Dennett there (mis)characterizes dualism as the doctrine that minds are “composed not of ordinary matter but of some other, special kind of stuff. . . ,” and materialism as the view that “there is only one sort of stuff, namely matter — the physical stuff of physics, chemistry, and physiology — and the mind is  nothing but a physical phenomenon.” (33) “In short, the mind is the brain.” (33)

But as I have said before,

A substance dualist such as Descartes does not hold that minds are composed of some extraordinarily thin intangible stuff. The dualism is not a dualism of stuff-kinds, real stuff and spooky stuff. ‘Substance’ in ‘substance dualism’ does not refer to a special sort of ethereal stuff but to substances in the sense of individuals capable of independent existence whose whole essence consists in acts of thought, perception, imagination, feeling, and the like. Dennett is exploiting the equivocity of ‘substance.’

The point is made very well by the prominent idealist, T. L. S. Sprigge:

It is often difficult to get people to realize that the non-physical mind of which Cartesians speak is not, as some have thought it, ‘a ghost in the machine’ of the human body, since ghosts and ‘spirits’ such as might appear in a seance are, in contrast to it, as physical, if made of a finer stuff, as our ordinary bodies. When we speak of the mental we do so mostly or entirely in metaphors (more or less sleeping) of a physical kind: we grasp ideas and have thoughts in our minds. Whatever the real source of this materialism which is endemic to most of our thinking, it is not surprising that there should be a theory of existence which follows its leadings. As thinkers we are subjects, but the natural object of thought is objects and it is only with effort that the subject turns its thoughts upon its own un-object-like nature. (Theories of Existence, pp. 46-47, bolding added.)

Dennett Plays the Interaction Card (Canard?)

Now Dennett trots out the “standard objection to dualism” which to Dennett is decisive. Ignoring non-interactionist types of substance dualism, Dennett tells us that mind and body, if distinct things or substances, must nonetheless interact. But how could the mind act upon the brain? How could a mental  make a difference to a brain state if mental states lack physical properties?

A fundamental principle of physics is that any change in the trajectory of any physical entity is an acceleration requiring the expenditure of energy, and where is this energy to come from? It is this principle of the conservation of energy that accounts for the physical impossibility of “perpetual motion machines,” and the same principle is apparently violated by dualism. This confrontation between quite standard physics and dualism . . . is widely regarded as the inescapable and fatal flaw of dualism. (35)

Now any unprejudiced person should be able to see that this “fatal objection” is inconclusive. Notice first of all that Dennett is presupposing that mental-physical causation must involve transfer of energy. For Dennett’s objection is essentially this:

a. Energy must be transferred to a physical entity to cause a change in it.
b. No energy can be transferred from an immaterial to a material entity.
Therefore
c. No immaterial entity such as a mind can cause a change in a material entity such as a brain/body.

But why should we accept the first premise? Why should we endorse a transfer theory of causation? Note that to assume a transfer theory of causation is to beg the question against the dualist: it is to assume that the mind must be material. For only a material thing can be a term in an energy transfer. Dennett thinks that dualism must collide with standard physics because he foists upon the dualist a conception of causation that the dualist will surely reject, a conception of causation that implies that there cannot be any nonphysical causes.

The materialist says: mind and body cannot interact because interaction requires transfer of energy, and only bodies can be the transferers and transferees of energy.

The interactionist dualist says: Since mind and body do interact, interaction does not require transfer of energy.

Let M be a type of mental event and B a type of brain event, and let m and b be tokens of these types. Perhaps there is nothing more to causation than this: m causes b =df (i) b follows m in time; (ii) Whenever an M event occurs, a B event occurs. On this regularity approach to causation, Dennett’s objection dissolves.

Indeed, on any theory of causation in which causation does not consist in a transfer of a physical magnitude from cause to effect, Dennett’s objection dissolves. Therefore, the objection can be made to stick only it is assumed that the transfer theory of causation is true of all types of causation. But then the question has been begged against dualist interaction.

There are two key points here that need to be developed in subsequent posts. One is that the nature of causation is not a physics problem. The natural scientist can tell us what causes what, but he is singularly ill-equipped to tell us what causation is. The second point is that it is not at all clear that causation, even in the physical world, is a physical process. It is not all clear, in other words, that the causal structure of the physical world is itself something physical.

Dennett thinks that the incoherence of dualism is so obvious that it doesn’t require “the citation of presumed laws of physics.” (35). Casper the Friendly Ghost is all the help one needs. He can pass through a wall, yet grab a falling towel. But that’s incoherent, since something that eludes physical measurement cannot have physical effects. The mind, as ‘ghost in the machine,’ is no better off. Only physical things can move physical things. But the mind of the substance dualist is not a physical thing, ergo, the mind cannot act upon the body.

But again, Dennett is just begging the question against the dualist as I have already explained.

. . . The objection to interactionism that causation, in either direction, as between psychical [mental] and physical events is precluded by the principle of the conservation of energy (or of energy-matter) is invalid for several reasons.

A. One reason is that the conservation which that principle asserts is not something known to be true without exception but is . . . only a defining-postulate of the notion of a wholly closed physical world, so that the question whether psycho-physical or physico-psychical causation ever occurs is (but in different words) the question whether the physical world is wholly closed. And that question is not answered by dignifying as a “principle” the assumption that the physical world is wholly closed.

B. Anyway, as C. D. Broad has pointed out, it might be the case that whenever a given amount of energy vanishes from, or emerges in, the physical world at one place, then an equal amount of energy respectively emerges in, or vanishes from that world at another place.

C. And thirdly, if “energy” is meant to designate something experimentally measurable, then “energy” is defined in terms of causality, not causality in terms of transfer of energy. That is, it is not known that all causation, or, in particular, causation as between psychical and physical events, involves transfer of energy. (Curt Ducasse, “In Defense of Dualism” in Sidney Hook, ed., Dimensions of Mind, Collier 1961, pp. 88-89)

I will now proceed seriatim through these points, supplying my own interpretation of them.

Ad (A). Any physicalist worth his salt will uphold the causal closure of the physical domain. That is just part (though not the whole) of what it means to be a physicalist. Borrowing from Jaegwon Kim, the principle may be stated thusly: Any physical event that has a cause at time t, has a physical cause at t. You QM enthusiasts out there will please note that this does not imply that every physical event has a cause. Note also that Kim’s formulation seems to allow for irreducibly mental events as causes of physical events. But if a physical event e is a sufficient cause of a physical event f, then any mental cause m of f will just be epiphenomenally along for the ride, if you catch my drift. In other words, m won’t do any work.

Adding to Kim’s formulation the notion that physical causes are sufficient for their physical effects yields a robust notion of causal closure. Robustly understood, the causal closure of the physical domain amounts to the thesis that all the causal work that gets done in the physical domain is done by physical events; if there are any irreducibly mental events, they don’t do any work in the physical domain.

Ducasse’s first argument, then, may be understood as follows. Appeal to conservation of energy is equivalent to appeal to causal closure of the physical. But one who objects to interactionist dualism on this basis begs the question against it by assuming the truth of a principle (causal closure) that immediately entails the falsity of interactionism.

The objection from conservation/closure is therefore not decisive against the interactionist. It would be decisive if the closure principle were known to be true. But that would be tantamount to knowing that physicalism is true. But we don’t know it to be true. Of course, physical science proceeds by searching for physical causes. That is the kind of game it plays. Its procedure is methodologically naturalistic. But there is a logical gap between methodological and substantive naturalism.

Ad (B). I don’t find Ducasse’s second point all that impressive. Assume conservation of energy. Then, if causation involves transfer of energy, and some mental events are causally efficacious in the physical domain, then energy must enter the physical domain at some point, call it the locus of interaction. Does this violate conservation of energy? Only if it is assumed that energy does not vanish at some other point. Since this is logically possible, the objection is not decisive. In other words, there could be a net conservation of energy or matter-energy in a system in which energy arose and vanished in different places.

Ad (C). Assume the causal closure of the physical domain. One could still be an interactionist dualist by denying that mental-physical causation involves transfer of a physical magnitude such as energy. Of course, if we know that every instance of causation is an instance of energy transfer, then of course we know (via some simple inferences) that mental-physical causation is impossible. But we don’t know this. Therefore, to object to interactionism on the ground that all causation involves energy transfer is to beg the question against the interactionist.

Note the difference between the first and third objections. The first objection begs the question against the interactionist by assuming that it is known that the physical domain is causally closed. The third objection begs the question by assuming that it is known that causation always involves energy transfer.

It looks like we ought to distinguish between the interactionist who accepts a transfer theory of causation but rejects causal closure, and the interactionist who accepts causal closure but rejects a transfer theory of causation.

Ducasse also alludes to the following point. Isn’t transfer itself a causal notion? How then can causation be analyzed in terms of transfer? Even if every instance of causation were an instance of energy transfer, that would not entail that causation consists in energy transfer. But this is a subtle point best reserved for a separate post.