This is an extract of our Essay Personal Identity document, which we sell as part of our Epistemology and Metaphysics Notes collection written by the top tier of University Of Oxford students.
The following is a more accessble plain text extract of the PDF sample above, taken from our Epistemology and Metaphysics Notes. Due to the challenges of extracting text from PDFs, it will have odd formatting:
What is it for a person to exist over time?
The notion of personal continuity is a complex one. Intuitively we are habitually certain that if we arrange on Wednesday to meet a friend on Thursday, the person that we do indeed meet on Thursday is the same person with whom we arranged such a meeting the previous day, but what precisely it is that determines that this is the case is unclear. Most simply, it is often physical or bodily similarity that makes us certain of personal continuity, but in more specifically philosophical terms a number of features have been advanced as indicators of continuity of identity. We should begin by making clear the nature of the 'persistence question' to which the title question directs us, before moving on to first examine empirical theories of personal identity and continuity. We will see that such theories are ultimately unsatisfactory, and should subsequently go on to examine a final theory of personal continuity that modifies the traditional language of identity itself, and I will conclude that it is likely that only through such a reformulation of our understanding of identity that any resolution to the search for a means of establishing personal continuity will be resolved. The 'persistence question' of personal continuity regards what it is for the same person to persist from one time to another - that is, to have existed without interruption from time a to time b - and asks what the necessary and sufficient conditions are for a past or future person to be you or I. The question regards numerical identity, rather than qualitative identity. a and b are numerically identical if they are one and the same thing, rather than two, whilst a and b are qualitatively identical if they are indistinguishable from each other - identical twins, for example. It is clear why qualitative identity does not affect the persistence question, since one can be expected to change over time, becoming taller, or thinner, or balder. One confusion we must be careful to avoid is not to understand the persistence question as asking what it is for someone to remain the same person over time, or whether losing my memory, or undergoing a dramatic change in personality would mean that I were no longer the person I was before. Whilst this seems intuitively similar to the persistence question, it is in fact unrelated to the question of numerical identity, since by the logic of identity nothing can make me numerically different from the person I am now - a person's numerical identity is immutable. We should begin, then, by examining empiricist theories of personal identity. Swinburne identifies what is meant by an 'empiricist' theory in this instance by positing two questions that relate to personal identity1:
1. What are the logically necessary and sufficient conditions for a person P2 at time T2 being the same as person P1 at time T1?
2. What evidence of observation and experience can we have that a person P2 at T2 is the same person as P1 at T1?
Swinburne suggests that many theories of personal identity give only one account for both questions,
since their understanding of the necessary and sufficient conditions for personal continuity is in terms of the 1 R Swinburne, Personal Identity: The Dualist Theory, in E Sosa and J Kim (eds.), Metaphysics: an Anthology (1999)
Buy the full version of these notes or essay plans and more in our Epistemology and Metaphysics Notes.