To: Stuart B.
From: Geoffrey Klempner
Subject: Hume on the problem of personal identity
Date: 18th February 2009 13:45

Dear Stuart,

Thank you for your email of 8 February, with your essay for the University of London Modern Philosophy Descartes. et. al. module, in response to the question, 'Why did the problem of personal identity cause Hume such severe difficulties that in the end he admitted that he could see no way of providing a coherent account?'

What is so special about the case of personal identity, that it should have caused Hume to see a problem which his own theory of identity in terms of 'fictions' was not able to solve? That seems to me to be the key question here.

Hume has a theory -- the theory of 'fictions' -- which although it is (by implication) an error theory, implying that we have false beliefs, nevertheless does a lot of work in explaining how we as human beings form the concepts that we are able to form.

This essay is about personal identity; however, it is important to see the problem in the context of what Hume says in 'On Scepticism With Regard to the Senses' where he finds an insuperable problem in accounting for the 'continued and distinct existence of bodies'.

As you state, the account of the fiction of identity goes like this: You are looking at an unchanging object. Because there is no difference in the quality of your successive impressions, your mind forms the idea of an identity, each successive impression belonging to the 'same' object.

In the case of the self, by contrast, there is as Hume observes, no 'object' given in experience whose successive impressions would even be capable of giving rise even to a fiction of identity. Here is the crucial passage (which you quote -- in fact twice, on successive pages!):

'That action of the imagination, by which we consider the uninterrupted and invariable object, and that by which we reflect on the succession of related objects, are almost the same to feeling.'

-- The annoying thing here is that Hume as a solution here, although he doesn't seem to realize it. There are two mental actions: recognizing sameness, and recognizing difference. In both cases, at least two perceptions are involved. But there are many such actions, and every additional action brings in more perceptions to the 'set'. Hence,

'I may venture to affirm of the rest of mankind, that they are nothing but a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity...'.

The bundle theory. Why isn't this a perfectly good theory of personal identity, given the constraints of Hume's theory of impressions, ideas and fictions? There is no identity across time, for anything. However, there is something that does the job of identity, for the things we perceive, and also for the self that does the perceiving.

Contrast now the case of the continued and distinct existence of objects: All that our experience of the world could ever teach us is that perceptual objects come into existence and go out of existence. Their nature depends on our perception. And yet, we somehow form the idea that one of these objects can exist *unperceived* and *distinct* from the act of perception. This truly is a contradiction which Hume has no way to solve, other than to remark that this is the point where we just have to recognize that philosophy has its limits (and he goes off to play a game of backgammon).

So I don't actually think that Hume is caught in an inconsistency with regard to personal identity, as you claim. That is not to say that the account can't be criticized. Logically, the explanation goes like this:

1. Ideas/ impressions A and B are bundled together if and only if there is an awareness of A with B. (Don't ask for the 'what' that bundles them together because no idea or impression corresponds to this.)

2. Any two bundles, large or small, which overlap give rise to a larger bundle which contains the ideas/ impressions which constitute the union of the ideas/ impressions in the two bundles.

3. At any given time, the self 'is' the bundle of all 'its' ideas/ impressions. All the ideas and impressions in the universe are thus divided up into distinct, non-overlapping sets. Any idea or impression I am aware of is part of 'me', and otherwise not.

4. Amongst the ideas in a currently existing bundle are ideas which represent ideas belonging to bundles which existed in the past (memories).

5. The sense of identity over time derives from memory: the fiction of a 'self' is constructed out of an awareness of a temporal succession of bundles of ideas/ impressions.

But still we are left with the question raised by the title of this essay: Hume evidently did feel unsatisfied with the account that he had given, as you quote, 'I cannot discover any theory, which gives me satisfaction on this head.' My feeling is, for what it is worth, that Hume is seeing beyond the logic of the bundle theory, realizing that it is after all merely a label for the problem to be solved, viz. the explanation of that in virtue of which perceptions get sorted into bundles in the first place.

What Kant saw and Hume missed, was that we are not required to find some physical or metaphysical 'glue' that accounts for the existence of bundles. This gets things completely the wrong way round. It is because experience has the given structure that it has, that it becomes possible to simultaneously form a hypothesis about a world of external objects and a self (itself an empirical object, like the objects which it perceives) which traces a path through that world. Beliefs concerning a unitary 'soul' merely arise because the mind mistakes the necessary identity of apperception for the 'perception of identity'. ('Paralogisms of Transcendental Psychology'.)

-- This of course also solves the problem with the continued and distinct existence of objects.

This is a good, careful piece of work (apart from the repeated quote). Despite what I've said here, an examiner would accept that you have made a good enough case for the claim of 'inconsistency'. I would give a mark in the upper 60's.

All the best,

Geoffrey