I don’t intend to make a habit of writing up notes for each meeting of section, but I thought that in this meeting we discussed some material that was complicated enough to make it worth the effort to quickly write up the main points covered.
After some preliminaries about identity, Leibniz’s Law, and the true solution to the Clark Kent/Superman puzzle, we focussed on Descartes’s argument for the Real Distinction between mind and body. I was pressing for a reading of Descartes which differed quite sharply from the reading Prof. Bays presented in his (excellent) lecture on 1/20.
The Conclusion of the Argument
The most important difference I have with TB is in our readings of the conclusion of the argument. Descartes argues that the mind is really distinct from the body. TB presented it as an argument for the non-identity of mind and body.
The Non-Identity of Mind and Body is a Very Weak Conclusion
The first thing to notice about the non-identity of mind and body is how weak a conclusion it is. I don’t think anybody — including the most strident physicalists — should deny this non-identity. In other words, even the most strident physicalists should avoid the claim that the mind is identical with the body. One way to illustrate how weak the non-identity conclusion is is to display a sound argument for this non-identity which utilizes premises everyone should accept. So, consider the Right Big Toe Argument, the main premises of which are:
1. My right big toe is a part of my body
2. My right big toe is not a part of my mind.
These two premises, together with Leibniz’s Law, yield the desired non-identity. The first premise is uncontroversially true. If there’s an interesting premise at all, it’s the second one. But it’s not very interesting. Even in my most physicalist of moods, I have no inclination whatsoever to deny the second premise. Truth be told, even in my most physicalist of moods, I have no inclination to deny the non-identity conclusion of the argument. We talked a lot about this point, so I’ll here just content myself with registering my opinion that this conclusion is too weak to be very interesting. (We discussed for a while whether the non-identity of self with body (I am not identical with my body) is an interesting conclusion, but I won’t summarize that here.)
Descartes’s Definition of Real Distinction
Fortunately, Descartes does not intend his conclusion to be so weak as this non-identity. He’s arguing for the real distinction between mind and body, and by “really distinct” he means something much stronger than non-identity. I don’t think he clearly explains his use of “really distinct” in the body of the Meditations. Fortunately, though, one of the “Objectors” asked Descartes to lay out the highlights of the Meditations in “geometrical” fashion, starting with definitions and axioms, and proceeding to the proofs of the main conclusions. Descartes complied with this request in the Second Replies, and in the “Geometrical Exposition”, we find this definition:
Definition X: Two substances are said to be really distinct when each of them can exist apart from the other.
— AT VII, p. 162 = CSM II, p. 114
What this definition amounts to depends a lot on the force of the “can” it contains (more on this below), but on any plausible reading, it means a lot more than non-identical. To illustrate this, consider a case of non-identity that Descartes wouldn’t count as a case of “real distinction”. In the Principles of Philosophy (see especially Principles 60-61), Descartes contrasts this notion of real distinction with the notion of “modal distinction”. This latter is the type of relation a substance bears to its own modes. I am not identical with (one and the same thing as) any of my modes. However, according to Descartes, my modes cannot exist without me. Thus, though they’re not identical with me, they’re not really distinct from me either.
The real worries Descartes is trying to combat, I’m fairly confident, are not that his mind — or even that he — might turn out to be identical with his body, but that (a) his mental properties might turn out to be modes of his body, with his mind itself being a mode or an aspect of his body or (b) it might turn out that, though his mind and his body are two non-identical substances, they might be so intimately and closely connected to one another that there’s no way for the one to be destroyed without the other going down along with it. To combat worry (a), he tries to show, not merely the weak conclusion that his mind is non-identical with his body, but the stronger, more interesting (in fact, downright contentious), and more hopeful (given Descartes’s strong interest in the prospects for continued existence after the demise of his body) conclusion that his mind is really distinct (and not just modally distinct) from his body — that it can exist without it. Indeed, as I’ll try to explain below, if the “can” of “can exist without” is strong enough, that conclusion will even help with worry (b).
Non-Identity and Meditation II
That the real distinction that Descartes proves in MVI is substantially stronger than mere non-identity provides a defense for interpretations of the type that TB attacked — interpretations according to which all the materials for the non-identity conclusion are available already in Meditation II. (I’m not advocating such an intepretation, but just noting that a proper understanding of Descartes’s conclusion provides a defense of such interpretations.) Against such interpretations, TB pointed out that Descartes not only waited until MVI to make the argument, but also insisted on several occasions that he wasn’t ready to make the argument — he didn’t have the necessary materials available — until MVI. Here’s another passage from a letter Descartes wrote, to the same effect:
You should not find it strange, either, that I do not prove in my second Meditation that the soul is really distinct from the body, but merely show how to conceive it without the body. This is because I do not yet have, at that point, the premises needed for the conclusion. You find it later on, in the sixth Meditation. –Letter to Mersenne, 24 December, 1640
But once we see that the conclusion Descartes reached in MVI is substantially stronger than mere non-identity, the fact that he felt he had to wait to establish that strong conclusion is compatible with his thinking he did have the materials for a much weaker non-identity conclusion earlier on. Perhaps God’s power is needed to establish the real distinction, but wouldn’t be needed for non-identity.
Now, I still think non-identity of mind and body is so weak a conclusion that Descartes was never really interested in that. But perhaps one might hope to find a case for the somewhat more interesting conclusion of non-identity of self with body in MII.
The Role of God in the Argument
When we actually look at the real distinction argument in the ninth paragraph of Meditation VI, we see that God plays a very large role in the argument. But, whatever other role God might be playing there, the key role is being played by God’s power. Though this is clear enough from Meditation VI itself, I think, it comes out even more clearly in the Geometrical Exposition, which was on the handout I distributed in section, but which I’ll here reproduce anyway:
(A) Geometrical Exposition
Definition X: Two substances are said to be really distinct when each of them can exist apart from the other.
— AT VII, p. 162 = CSM II, p. 114
Proposition IV: There is a real distinction between the mind and the body
Demonstration: God can bring about whatever we clearly and distinctly perceive in a way exactly corresponding to our perception of it (preceding Corollary). But we clearly perceive the mind, that is, a thinking substance, apart from the body, that is, apart from an extended substance (Second Postulate). And conversely we can clearly perceive the body apart from the mind (as everyone readily admits). Therefore, the mind can, at least through the power of God, exist without the body; and similarly the body can exist apart from the mind.
Now, if one substance can exist apart from another the two are really distinct (Def. X). But the mind and the body are substances (Defs. V, VI and VII) which can exist apart from each other (as has just been proved). Therefore, there is a real distinction between the mind and the body.
Notice that I introduce the power of God as a means to separate mind and body not because any extraordinary power is needed to bring about such a separation but because the preceding arguments have dealt solely with God, and hence there was nothing else I could use to make the separation. Our knowledge that two things are really distinct is not affected by the nature of the power that separates them.
— AT VII, pp. 169-170 = CSM II, p. 119
Following Descartes’s own summary of the argument very closely then, we can safely take the basic structure of the argument to consist of two premises — a God’s power premise and a conceivability premise — as follows:
1. God can bring about whatever we can clearly and distinctly conceive.
2. We can clearly and distinctly conceive of the mind existing without the body, and of the body existing without the mind.
Therefore, C. The mind can exist without the body, and the body can exist without the mind.
Now this looks very different from TB’s rendering of the argument, since it leaves out all the stuff about real essences, etc. But this difference is not as great as it appears, because, following Descartes, I’m only giving here the basic structure of the argument. Descartes was rightly subjected to a lot of pressure about this argument being too powerful. If we accept it, how will we reject various parallel arguments that we all reject? Can’t someone conceive of a right triangle without seeing that the square of its hypotenuse is equal to the sum of the square of its other two sides? Can’t such a person conceive of a right triangle of which the square of the hypotenuse is not equal to the sum of the square of the sides? And does this show that a right triangle can fail to satisfy the relevant geometrical theorem, since God can bring about whatever this person can conceive? (See Objections IV, AT 201-202; those with the Cottingham translation (the green book) can find this on p. 109 of their books.) Under such pressure, Descartes puts a lot of weight on the “clearly and distinctly” part of “clearly and distinctly conceive”. Nobody clearly and distinctly conceives of a right triangle in the way described. Well, then, what does it take to clearly and distinctly conceive of something in such a way as to assure you that God can bring about the scenario conceived? Descartes has a lot to say here, and it takes us down a long, torturous path through substances, “complete” conceptions, where the method TB discussed of discerning something’s essence seems to play a role, and at least arguably into the realm of real essences and whatnot. And this is all to be expected, since the argument in Meditation VI certainly makes use of the notion of my “nature” and “essence”. Here, for convenience is the argument itself:
(B) Ninth Paragraph of Meditation VI
First, I know that everything which I clearly and distinctly understand is capable of being created by God so as to correspond exactly with my understanding of it. Hence the fact that I can clearly and distinctly understand one thing apart from another is enough to make me certain that the two things are distinct, since they are capable of being separated, at least by God. The question of what kind of power is required to bring about such a separation does not affect the judgement that the two things are distinct. Thus, simply by knowing that I exist and seeing at the same time that absolutely nothing else belongs to my nature or essence except that I am a thinking thing, I can infer correctly that my essence consists solely in the fact that I am a thinking thing. It is true that I may have (or, to anticipate, that I certainly have) a body that is very closely joined to me. But, nevertheless, on the one hand I have a clear and distinct idea of myself, in so far as I am simply a thinking, non-extended thing; and on the other hand I have a distinct idea of body, in so far as this is simply an extended, non-thinking thing. And accordingly, it is certain that I am really distinct from my body, and can exist without it.
— AT VII, p. 78 = CSM II, p. 54
So I’m not out to deny the importance of such notions as natures and essences to Descartes’s argument. It is noteworthy that in his own GE version of the argument, these appear to drop out. But since they’re probably being smuggled in anyway under the banner of the clarity and distinctness of the conceptions involved, I don’t want to make too much of that. What I do want to insist on, though, is that we give a role to God’s power, which, as the GE version shows (but which really is pretty clear already in MVI), is absolutely critical to the argument.
Descartes’s “Can” and the Hope of Survival
Recall our discussion of the slipperiness of the word “can”. (Recall the sense(s) in which I can, and the sense(s) in which I cannot be in Chicago tomorrow night.) I think the only way to allow God’s power play the key role it quite clearly does play in Descartes’s argument is to understand Descartes’s “can” in a very “thick” way. (Well, I don’t think the understanding is unusually thick relative to most uses of “can”, but it is unusually thick relative to most philosopher’s uses of “can” in such settings.) To make it true, in the relevant sense, that my mind can exist without my body, it’s certainly not enough that it be non-identical with my body, and it’s not even enough (though this is certainly much more) that it’s “metaphysically possible” that my mind should have existed without my body, or without any body. There has to be a real potential for my mind to exist without my body: There has to be a power in universe capable of making that be the case.
Consider an analogy — a strange analogy, but it makes the point, I think. Suppose you live on an island where there’s a trap so powerful that once someone falls into it, only a God could ever free her from the trap. One day, some fellow islanders get drunk, and get it into their heads that it would be fun to throw you into the trap. They chase you, and you flee and almost escape, but they do manage to catch you and throw you into the trap. And there you sit. You can easily conceive of yourself as existing apart from the trap. Indeed, you once were apart from it. And you came so close to escaping your attackers that it’s not only “metaphysically possible” that you should have been, even right now, apart from the trap, but it’s only a matter of bad luck that you’re sitting there stuck in it. Still, none of that gives you much grounds for hope. However, you’ve heard that there may be a God, and you’ve even heard rumors to the effect that this God is favorably disposed toward freeing folks from such traps. There seems to be a fairly clear sense of “can” in which the issue of whether or not you can ever be freed from the trap depends on whether a God with such power does exist — whether there is a potentiality in the universe for your being freed. Philosophically speaking, this is a pretty thick “can”.
Could Descartes have meant anything so thick? Well, with all this in mind, take another look at the proof for the Real Distinction — both in the Geometrical Exposition and in Meditation VI, and judge for yourself. I think the argument makes great sense where the “can” is understood in such a way. Plus, I don’t see any other way to give God’s power the place it seems to deserve in Descartes’s argument.
I think such an understanding of Descartes’s conclusion is often missed because due to a failure to respect one of the main sources of Descartes’s interest in the relation between mind and body. If your interest is only the metaphysical one of understanding the nature of the mind, you’ll probably want a much “thinner” “can” than the one I’m claiming Descartes uses. Recall your predicament on the island. If your only interest were the metaphysical one of understanding what your nature is, it doesn’t matter whether any God exists. Metaphysically, your existence doesn’t depend on your being entrapped. Learning that God exists, and that, in the “thick” sense described above, you really can be freed from the trap, doesn’t help you to further understand your nature. And what difference does it make to the nature of the mind whether there’s a power out there capable of making it exist without the body? For the metaphysician, once you know that the mind “metaphysically” (very “thinly”) can exist alone, you’ve got all you want. And Descartes certainly was a metaphysician interested in the nature of the mind.
But he also had a very strong practical interest in the relation between mind and body. He wanted, as he put it in the Synopsis of the Meditations, “to show that the decay of the body does not imply the destruction of the mind” and to thereby “give mortals the hope of an after-life” (AT 13, on p. 10 of the green books and p. 9 of the white book). And he makes it clear that this practical interest played a very large role in why he was investigating the relation between mind and body in the Meditations. With such a practical interest — not unlike your practical interest on the island — strongly in play, the issue of whether you can exist without your body, in the “thick” sense of “can”, is very relevant indeed.
To be sure, one can derive even more hope from the knowledge that, not only does a God powerful enough to make my mind survive the demise of my body exist, but this God is favorably disposed toward the prospect of doing so. Descartes doesn’t think he can, through philosophy, give us that much hope. But he does think he can give us fairly strong grounds for hope — and a lot stronger grounds than one could get merely by demonstrating the non-identity of mind and body (which I don’t think anybody should deny anyway), or by merely showing that it’s metaphysically possible that the mind should have existed without the body.
A final issue: In the Geometrical Exposition version of the argument, and perhaps (though less clearly so) in the Meditation VI version, Descartes hints that, although he utilized God’s power to demonstrate the real distinction, that doesn’t mean he thinks it takes omnipotence to effect the distinction of mind and body. The hint seems to be that, though he uses God since God’s the only thing he’s proven to be powerful enough to effect the separation, he in fact believes that something so comparatively weak as, say, a well placed shot from a handgun could effect the separation and make my mind exist without my body. But whether Descartes is entitled to the position hinted at there is a very tricky manner, given his views on Continual Re-Creation — that in order for a substance to continue to exist, God must re-create it anew at each moment (that God must use the same power to cause it to exist at each new moment as He used in creating it in the first place). (Those who like good philosophical puzzles might want to think about this tricky issue.)
But it’s alright, Ma, it’s life, and life only.