Identity

A. We think of identity in two ways:

  1. a-temporal identity, e.g. 3+2 = 5.  (Since numbers are not in time, their relations are a-temporal)
  2. temporal identity:
    3.           example: what makes a ship yesterday the same ship as today?
    NOTE: here we'll study diachronic identity
Righty or wrongly, pre-philosophically, we also distinguish between numerical and qualitative identity, and hold that B. Two basic approaches to diachronic identity:
  1. Substantial approach: a continuant  endures, like the kernel of a thing, wholly existing at each time, without temporal parts, and unchanged through time, thereby providing diachronic identity.
  2. Relational approach: there are various successive thing-stages S1,....Sn  which, when  appropriately linked (e.g. causally), constitute one thing O existing through time.

    3. NOTE:
    1. O doesn't wholly exists at any time t at which S1,..Sn exist, in the same way in which a spatially extended object M doesn't wholly exists in any place in which any if its parts exists.  O is "extended" in time just as M is extended in space.
    2. O is a perduring continuant, each part of which exists at a time only.
    3. This view is similar to that of continuous creation, but with causation in rebus.
C. Personal Identity

1. Two points suggested by language and our pre-philosophical views:

  1. there's some entity to which the various experiences are attributed (experiences are owned, they don't float around, as it were).
  2. experiences are owned by the same subject  at different times ("I" seems to refer to the same subject at different times).
2. The two basic approaches to identity applied to personal identity:
  1. Substantial approach: experiences are exemplified or inhere in a single enduring continuant which constitutes the person (Reid, Chisholm., etc.)

    2. Hence:
  2. Relational approach: the experiences subsist prior to the person, and the person is nothing above experiences appropriately related.

    3. Hence:
3. Development of a memory based relational approach (quasi-Locke)

This theory of identity makes use of two basic ideas, psychological connectedness and psychological continuity:

Two person-stages Q and R are person-stages (temporal parts) of the same person P iff they are psychologically continuous.
NOTE: hence possibility of personhood transfer from one thing (e.g., brain or soul) to another (tele-transportation).
NOTE: It's possible to add further requirements for psychological connectedness, e.g., character, basic beliefs, etc.
Problems: 4. Development of substantial approach: see Reid and Chisholm below

Hume: On Identity and Personal Identity

1. Hume's analysis of identity is based on the juxtaposition of two notions, that of identity and that of a succession of related things

  1. The idea of identity is that of a thing which goes through time as invariable and uninterrupted.

    2.  NOTE: this is a strict substantial theory of identity.
  2. The idea of succession of related things is that of several things existing in  succession and linked by a close relation.

    3. NOTE: This is close to the relational theory of identity.
2. We tend to confuse these two ideas and assume that there's identity when a succession of items linked in an appropriate relation is all there is.  For example, we confuse the following cases of succession with ones of identity 3. Personal identity
H. notes the following: Consequently, concerning the self: 4. So, issues of identity are merely verbal, except in so far as often we confabulate on our confusion by invoking the existence of something persisting along the  succession, e.g. substance. This especially evident in the case of PI, when we appeal to the self or the soul.
NOTE: The problem, then, is that with respect to things or persons, all we get is a relational theory of identity, while for H. what's needed is the strictest substantial theory of identity.

Reid: Of Identity

1. The belief of my identity through time is pre-philosophical and absolutely fundamental: since human reasoning is successive, memory is required for thought, and it's impossible to have memory without personal identity.

2. Identity is a relation between two things known to exists at different times, and it presupposes an uninterrupted continuance of existence.
NOTES:

3. The self is a unity as the necessary unity of consciousness shows.  Hence, PI involves the continued existence of the self (a soul).
  Problem: How do I know my self persists?
  Reply:


 PI of myself is:

 PI of others is: 4. Identity of objects:

Chisholm: Problems of Identity

1. Three puzzles, (A), (B), (C):

A)
Elm st. and Peach st. both start at S, go together for a while and then split going to P and Q ( a Y shape). If I start at A and stay on the same street, do I end up at P or Q?
Solution:

B)
Theseus’s ship variation: start with a boat at t1; then, change its boards; suppose now that at t2 the boat undergoes fission, so that at t3 we have 2 boats, one northbound and one southbound.  If you boarded at the beginning and remained on same ship, would you be on the one going south or going north?
Solution:
same as above.
NOTE: Both in (A) and (B), street spatial stages and ship temporal stages are intrinsically unconnected to each other much as Edwardian people (continual creation), with no enduring continuant.

C)
I know at t1 my body undergoes fission at t2 and that at t3 there will be two men, X and Y, such that X has my brain waves, fingerprints, genetic markers but none of my memories, and Y different brain waves, fingerprints, etc., but my memories.  Will I   be Y or X?
NOTE: the previous solution doesn't work. PI is an intrinsic feature of persons because of the unity of consciousness (it would be hard to imagine that what makes me, say, X is the fact that some people decided that I'm X).

2. The unity of consciousness is both:

Hence,