To: James V.
From: Geoffrey Klempner
Subject: Strawson's claim that Cartesian souls cannot be individuated
Date: 23rd October 2008 11:33
Thank you for your email of 14 October, with your University of London Introduction to Philosophy Essay, in response to the question, 'Strawson states the principle: 'If we are to talk coherently about individual consciousnesses or minds we must notice the difference between one such item and two such items.' Is this principle correct? Does it create a problem for Descartes' account of the mind?'
You have gone all around this question, but I am not sure that you have answered it adequately. The main virtue of your essay is your stress on the positive, and valuable aspect of Descartes' insistence on the special nature of introspection. This is important, because whatever we say about the mind, we don't want to be forced into a conclusion which denies the reality of introspection, or its value as a source of genuine knowledge.
The question is in two parts. In the first part, you are asked to say whether you think 'this principle' is correct. Which principle? On the face of it, the principle is the one stated in the question, 'If we are to talk coherently about individual consciousnesses...'. However, the *general* principle in question is, 'If we are to talk coherently about F's, for any thing identified as being 'an F', we must notice the difference between one F thing and two F things.'
Well, is the principle correct? Towards the end of your essay, you say, 'Even if we were to look at two roses, for example, while they might look and seem the same, their innate cells might differ somewhat.' However, this is not the kind of 'identity' Strawson is talking about. There is no logical reason why there could not be two roses which were *qualitatively* identical in every respect. (The philosopher Leibniz famously denied this, but that is a separate issue which relates specifically to Leibniz's philosophy of 'monads': more below.) What makes the two 'identical' roses two, is simply their different spatial location. That is all we require to count roses, or indeed any material entity.
In other words, the 'identity' in question is numerical identity, or being 'one and the same F'. Suppose there is a twin James Vanstone on twin Earth, he is not you, even if he is thinking the very same thoughts, doing the same actions as you are doing now. By hypothesis, 'twin earth' is somewhere out there in space. There are two Earths, earth and twin earth, and hence two JV's, JV and twin JV.
Now, you might think that this principle is too strict. Surely there are 'things' we can talk about, which don't have clearly delineated 'criteria of identity'. For example, clouds or mountains. When do you have one mountain with two peaks, or two mountains? So there is a question here whether the identity principle allows any margin of vagueness.
However, Strawson's case against Descartes is not undermined by worries about vagueness. Strawson's argument is that qualitative identity is not sufficient for 'being one and the same'. In addition, we require spatial location. But souls by definition are not located in space. Therefore souls do not have criteria of identity.
The problem isn't only, as you seem to suggest, that I might legitimately speculate that 'James Vanstone' is two or twenty souls, all thinking their thoughts in unison. When I look into myself, nothing that is presented to my consciousness tells me that there is one GK rather than twenty GK's.
The same point can be made about the identity of a soul over time. You give a good example of how we can speak of the identity of a person, say Hitler, over time, despite considerable physical and mental changes. However, if the concept of mind or soul is cut loose from the physical, as Descartes claims that it is, then there would be no difference, in reality, between the hypothesis that JV or GK 'dies' every second and is replaced by a qualitatively indistinguishable JV or GK, and the hypothesis that GK or JV continue. (This point was made by Kant in his 'Critique of Pure Reason'.) Again, it makes no difference whether you are talking about me, or me about you, or each of us is gazing inwards trying to 'track' our own identity through time. There is nothing to track. The phenomena in themselves do not point to identity or non-identity, for the very reason that things would phenomenologically *appear* just the same either way.
Why space? I remember as a student at Birkbeck long ago answering this question (or a similar question) thinking that Strawson is simply assuming from the start the very thing that Descartes denies: that the only time we can speak of numerically different entities is when we are speaking of spatio-temporal particulars. Why can't Descartes just lay it down, as an absolute metaphysical principle, that even if we allow that there can be 'qualitatively identical' physical things, it doesn't follow that we have to allow that there can be qualitatively identical mental things. So the criteria of identity for a soul or mind is simply its unique mental properties, which no mind, in principle, can possess.
There is one possible way in which one might defend this objection, or at least a version of it. That requires denying the reality of space altogether, and hence denying Cartesian dualism, in favour of a Leibnizian view, where reality as such is constituted by unique points of view, or 'monads', each point of view being uniquely characterized by its subjective qualities. This is not good news for Descartes, although in the absence of any alternative he probably would have preferred Leibniz's mental monism to Hobbes' physical monism.
All the best,