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3.5.2: II

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    In the above section I have tried to develop four separate arguments in order to show that it is inaccurate to say that according to Locke personal identity consists in memory, that memory is the criterion (in the strong sense) of personal identity.[11] Rather it appears that Locke thinks that personal identity consists in spatiotemporal continuity of consciousness in rather the same way in which the identity of a tree consists in spatiotemporal continuity of a 'common life'. Memory is good evidence (perhaps for us the best evidence) for such continuity in rather the way that observations of the tree are good evidence for its continued identity as a tree. I want to support this line of reasoning by making a number of more general observations.

    Locke undoubtedly thinks of memory as being necessary for personal identity, but in what sense he takes it to be necessary requires carefully spelling out. There are three senses in which he regards memory as necessary and each of these falls short of memory being logically necessary for continued personal identity. In the first place Locke does allow that it is logically necessary for being a person at a given time that the individual in question has the capacity to remember. Such a capacity seems to be part of what Locke means by 'consciousness'. A person 'can consider itself as itself, the same thinking thing in different times and places' (section ix). But it is not logically necessary for being the same individual as someone in the past that one remembers certain things in the past. So that to say 'Memory is logically necessary for personal identity' is ambiguous. If it means 'Memory is logically necessary for something's being a person at a time' then Locke is committed to this by his view of consciousness. If it means 'Memory of doing A is logically necessary for being the person who did A' then there is no evidence that Locke held this view.

    But he did hold that memory was necessary for personal identity in other senses. It is epistemically or evidentially necessary, necessary for knowing that one is the same person as some individual in the past. Throughout his treatment of this topic Locke assigns priority to direct memory as against indirect memory. At the Great Day it will not be sufficient for God to tell me what I am responsible for. I must remember what I am responsible for for myself. At present it is not epistemically necessary that someone else should remember, but it is that I should remember myself. 'Whatever past actions it (viz. the self) cannot reconcile or appropriate to that present self by consciousness, it can be no more concerned in than if they had never been done' (section xxvi). This links with Locke's strongly forensic emphasis. Memory is necessary in order for me to have evidence that I am identical with some person in the past and hence necessary for me regarding myself (and being justly regarded by others) as responsible for some action in the past.

    Further, what is logically sufficient for being the same person is that the individual consciousness in question can recall some action in the past, not that he does recall it. Locke emphasizes this point in various ways, straight- forwardly in his first statement about his concept of a person (section ix), and then negatively when he considers the possibility of an incommunicable consciousness (section xx), and the possibility of losing a memory irretrievably, and the possibility of two incommunicable consciousnesses 'acting the same body' (section xxiii). Finally in section xxvi he considers the case of a man punished now for what he had done in another life 'whereof he could be made to have no consciousness at all' and asks: 'What difference is there between that punishment and being created miserable?'

    While Locke emphasizes in such passages the logical possibility of memory being logically sufficient for being the same person this is not to be taken as implying that Locke thinks that in fact memory is generally untrustworthy. An individual consciousness does not have to remember everything that it has done, only some of the things, and Locke seems never to doubt that the human memory has such powers. But because memory is only logically sufficient for continued personhood, this practical emphasis in Locke does not mean that he is open to the objection that he allows personal identity to be limited by what an individual consciousness can recall at any time, and that an individual consciousness might recall different things at different times. If individual consciousnesses could in fact recall very little then this would be a difficulty, but in fact they are quite successful, and hence the appeal to memory is of practical use, as well as having the theoretical role that I have tried to indicate above.[12]

    So the relation between memory, consciousness and personhood assumes more complicated proportions than is usually thought. The essential features of this relationship can be expressed in the following five theses

    1. Spatio-temporal continuity of consciousness is logically necessary and sufficient for personal identity over time.
    2. Consciousness, including the ability to remember, is logically necessary and sufficient for being a person at any given time.
    3. Augmented or ideal memory is logically sufficient for continuous personal identity and hence for personal responsibility for past actions. 
    4. Memory is evidentially necessary and sufficient for personal identity over time, for an individual consciousness knowing that it is identical with some individual consciousness in the past.
    5. Unaugmented memory is logically sufficient for continuous personal identity.

    It would seriously misrepresent Locke's views to add to these five theses the thesis that unaugmented memory is logically necessary for continued personal identity and hence for personal responsibility for past actions.

    [11] Like Mackie I think that it is necessary not to slur over the distinction between truth-conditions and evidence by the use of the term 'criterion' (Mackie, op. cit., i85-I 86). By 'criterion in the strong sense' I mean 'truth-conditions'. 

    [12] Cf. Hughes, op. cit., I72.


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