Butler on Identity

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Butler selection on identity
Butler aims to criticize Locke's memory theory, and especially the idea that the self might be something other than a substance.

• Butler argues that whether a person is the same person over time (e.g., whether one body harbors the same person over time) should be seen as a question of "similitude or equality."
• Butler's standard for similitude or equality appears to be very strong: something on the order of Leibniz's principle of the indiscernability of identicals. In second order logic, (a=b) --> /\F(Fa <--> Fb).
• Butler makes on important distinction, however: he includes that we perceive that identity is the same over time. Thus, any properties directly concerned with time are apparently ruled out.
• What then is this thing that has all the same properties (except for, for example, age) over time? It is some special substance.
• Butler's notion of this substance might be something like the collection of essential properties of the self. Otherwise, it would seem to fall to Locke's poignant criticism that spiritual substance should be like material substance and change to explain changes (we learn, for example).
• Butler argues that the idea of consciousness presupposes a self existing over time.
• Locke's use of the word "same" must not really be the right use of the word "same," Butler concludes. (I think that Locke could grant this without harm to Locke's position, by just noting that his use of "same" and Butler's use of "same" are different, but that both are as good a candidate for the colloquial use.)
• Butler describes three problems with a lack of personal identity. He means to attack Locke, but we might best read him to see some problems with any denial that there is a personal identity.
  1. A person who did not believe that he would exist tomorrow (e.g., that his body would not include him tomorrow) would not care about his conduct now. (NOTE: Parfit makes a virtue of something quite like what Butler thinks is here a vice: he argues we should not be selfish because our future selves are not much closer to our present selves than many other people's self now or in the future.)
  2. To say a being suffered or enjoyed is to admit that the being endured over time. We cannot deny that individuals endure without denying our use of such claims.
  3. We know that we are the same as the person we once were. This is recognition of a substance that exists in both times.