What are minds, and how are they related to bodies and other physical stuff?

Descartes’ Dualism

    Descartes contends that a person or human being such as you or me is a two-part composite, of a mind and a body.  (Alternatively speaking, the person is just the mind but has a body.)  And according to him, a mind is an entirely immaterial, nonphysical thing, not even located in physical space.  Yet what unites a mind with a particular body is that it causally interacts with that body, in a distinctively intimate way.
His main argument is this:

    1.  I can doubt that my body [or any other physical thing, such as my brain, or anything with any spatial properties] exists.

    2.  I cannot doubt that my mind exists.
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So 3.  My mind is distinct from my body [and from every other physical thing, such as my brain, or anything with any spatial properties].   [1,2]

    Several objections were made in class.

    Objection 1:  Cartesian minds seem to flout well-established science.  (a) They are supposed to be in real time even though they are not in space; but according to General Relativity (?), nothing can be in time but not in space.   (b) It doesn’t seem that immaterial entities could cause physical motion consistently with the conservation laws of physics, such as conservation of motion and conservation of matter-energy; physical energy would have to vanish and reappear inside human brains, which from the scientific point of view would have to be magic.  Reply:  It’s possible that that does happen, in the inner recesses of human brains.  Who says it doesn’t?  No one has ever shown that it doesn’t.  Rejoinder:  But in view of the generality of physics, that’s not very likely, is it?
    More generally, Cartesian minds fit ill with our otherwise physical and scientific picture of the world, uncomfortably like ghosts or ectoplasm.  They are not needed for the explanation of any publicly observable fact, for neurophysiology promises to explain the motions of our bodies in particular and to explain them completely.  Ghost-minds are scientific excrescences.  Reply:  Despite WGL’s constant references to Descartes’ “theory,” Cartesian minds are not scientific posits, hypothesized to explain physical events.  They are known from the inside, and shown to be nonphysical by Descartes’ Doubt argument.  If they’re scientifically ill-behaved, too bad.

    Objection 2, the Interaction problem:  How could a thing so utterly nonphysical as a Cartesian mind directly affect your physical body, or be directly and intimately affected by it?  Replies:  Descartes first appealed to the pineal gland, as the gateway or locus of mind-body interaction.  But (rejoinder by Princess Elisabeth of Bohemia<1> :) the pineal gland is just another physical entity; so that appeal is no answer to the question of how a Cartesian mind could interact with anything physical.  Descartes then likened mental causation to the force of gravity; gravity isn’t a physical object like a billiard ball or a fist, yet it causes physical motion.  But (rejoinders:) gravity is physical in at least the weaker sense that a gravitational field is always the gravitational field of some physical object; also (her Highness again), gravity is physical in Descartes’ own favorite sense of being a spatial phenomenon and working according to well known laws of physics.  The trouble with Cartesian minds is that they do not have any spatial properties at all.

    Objection 3, Ryle’s epistemological objection:  Descartes’ picture makes it a complete mystery how we could ever know what’s going on in someone else’s mind.  All we perceive of another person is her/his body; what could possibly license an inference from physical observations to a conclusion about immaterial goings-on in a nonphysical, nonspatial substance?  Reply (Johnathan):  On Descartes’ view, relevant bodily motions, speech in particular, are caused by mental states and events.  In everyday life we usually do know things by way of their observable effects, so it’s not a complete mystery how we could know things about Cartesian mental states.  Rejoinder (Ryle):  All right, but Descartes still gets the shape of the epistemology wrong.  We don’t have to perform a risky inference from effects to ghostly causes.  Often we know perceptually what is going on in someone else’s mind:  We know what they think because we hear them say it; we can just see that the accident victim is in terrible pain.  Also, we often know another person’s mental state—a mood, say, or a belief—better than they themselves know it; on Descartes’ view that is impossible.

Evaluating the Doubt argument

    Although the argument may at first sound correct, it is not valid.  In general, from “I can doubt the existence of X; I cannot doubt the existence of Y,” we cannot infer that X and Y are distinct.  Compare:

    1.  I can doubt that the winner of the 1999 All-Ohio Cross-Dressing Contest exists.  [Say, because I doubt that there is any such contest.]

    2.  I cannot doubt that my daughter exists.  [Say, because she is standing right in front of me and we are chatting.]
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So 3.  My daughter is not the winner of the 1999 All-Ohio Cross-Dressing Contest.   [1,2]

Behaviorism

    The Behaviorists held that to ascribe a mental state to someone is only to say something about that person’s actual or hypothetical behavior.  To be in pain is just to behave, or at least be disposed to behave, in the ways we stereotypically associate with pain—crying out, wincing, favoring the injured part, etc.  To be sad is to be disposed to weep, to droop, not to show enthusiasm, etc.  To believe that motorcycles are dangerous is just to be disposed to say that they are, to avoid them, to recommend them warmly to your enemies, etc.
    The Behaviorist theory avoids all three of our objections to Cartesian Dualism at one stroke.

    But.  (As always.)  Objections to Behaviorism:

    Objection 1:  The Behaviorist identifies each mental state with a specific behavioral disposition.  But that presupposes that every type of mental state has a unique, identifiable behavioral syndrome, and we can’t be sure that’s true.  In particular, the behavioral syndromes associated with a given mental state may vary across cultures—say, when an American is embarrassed, s/he tends to blush and shrink and mumble, while an embarrassed Chinese laughs loudly.  Reply:  There can’t be all that much cultural variation, or actors would not be able to do their thing on stage.  And where there is, it may be that the relevant word, such as “embarrassed,” means something somewhat different as between the two cultures.  Even if not, we can simply relativize the associated behavior to culture; that does not seem to affect Ryle’s identification of mental states with behavioral dispositions.

    Objection 2:  It seems inescapable that there are, in some sense, inner mental episodes that we know from the inside—thoughts, feelings, experiences, that occur in real time and that aren’t constituted either by any actual behavior or simply by the mere truth of a hypothetical “If X were to happen, you would do Y.”  Indeed, we introspect them.

    Objection 3:  The Behaviorist maintains that for a person to be in mental state M just is for that person to have the appropriate behavioral disposition, and vice versa.  That entails that it is impossible for anyone to have the appropriate behavioral disposition and yet not be in M; no mental difference without (at least a dispositional) behavioral difference.  But it is perfectly possible to be behaving in all the right ways and have all the right hypothetical/dispositional properties too, yet not be in the associated mental state.  Examples:  Inverted spectrum; the Tinfoil Man.