Psychological Connectedness and Personal Identity
Let P1 and P2 represent persons. What makes a person at some time, t, identical to themselves at a future time, t*? What makes 'Joel right now' identical to 'Joel one year ago', or what will make 'Joel right now' identical to 'Joel one year from now'? The psychological criteria for personal identity goes as follows:
P1 is identical to P2 iff (if and only if) P1 at t is psychologically connected with P2 at t*.
P1 at t is psychologically connected with P2 at t* iff t* is later than t and "[P2] believes at t* a good bit of what [P1] believed at t, [P2] wants at t* a good bit of what [P1] wanted at t, [P2] seems to remember at t* a good bit of what [P1] experienced at t, and so on" [1].
Consider the character, Fred. Imagine that Fred's brain is surgically removed from his head and transplanted into the head of a different body (assume that the new body had its original brain removed). If, after the surgery, the survivor wakes up and claims to be Fred, has similar tendencies, beliefs, and memories as Fred, then the survivor is Fred, according to the above criterion. The pre-surgery Fred is psychologically connected with the survivor, and vice versa. Intuitively, we would want to affirm that Fred woke up from the surgery, even if he has a new body [2].
THE DUPLICATION DILEMMA
I submit that the psychological criteria for personal identity is not sufficient to guarantee personal identity. Consider a situation wherein Fred's brain is scanned and destroyed, and two separate brains are remodeled after Fred's brain and placed into the heads of two distinct bodies, resulting in two people: Bob1 and Bob2. Bob1 wakes up and is psychologically connected with Fred. Bob2 wakes up and is also psychologically connected with Fred. According to psychological criteria, both Bob1 and Bob2 are Fred. If Bob1 = Fred, and Bob2 = Fred, then Bob1 = Bob2. This is impossible. If Bob1 and Bob2 are experiencing their own stream of consciousness, from distinct vantage points and at the same time, they are not numerically identical. The psychological criteria, then, leads us to affirm logical absurdities.
METHOD FOR SALVAGING PC: THE 'NO COMPETITORS' CLAUSE
One can attempt to salvage the psychological criteria by adding a 'no competitors' clause:
P1 is identical to P2 (i) iff P1 at t is psychologically connected with P2 at t* and (ii) iff P1 is not psychologically connected to P3 at t* (in other words, there are no competitors with P2).
However, as Judith Thomson argues, the no competitors clause makes personal identity hinge on a matter that should be irrelevant to personal identity. If an exact replica of Fred's brain is placed inside Bob1's head (with the original brain being destroyed) and Bob1 wakes up acting like Fred and remembering most everything that Fred had experienced, we would likely be willing to say that Bob1 is Fred -- in other words, Fred survived the surgery. If, however, Bob1 and Bob2 receive replicated Fred-brains and each survives the surgery and each is psychologically connected to Fred, then they are not identical to Fred, or it is indeterminate whether they are identical to Fred, according to the no competitors clause. But surely, argues Thomson, if psychological connectedness is a good mark of personal identity, the survival of Fred and the identity of the post-surgery survivor(s) should not hinge on such peculiar circumstances as whether Bob2 (or Bob1) survives the surgery or whether two replicas of Fred's brain are created. Since it does, the no-competitors clause cannot salvage psychological criteria and, therefore, psychological connectedness is not a good criteria for personal identity [3].
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Footnotes:
[1] Thomson, Jidith J. "People and Their Bodies." Contemporary Debates in Metaphysics. Ed. Theodore Sider, John Hawthorne, and Dean Zimmerman. Oxford: Blackewell, 1997. 160. Print.
[2] The narrow psychological criterion states that both psychological connectedness and having the same brain are marks of personal identity. Thomson argues that it should be irrelevant whether the same lump of neurons and matter are preserved, so long as "psychological transplanting" occurs (Thomson: 159).
[3] Thomson writes, "...if the identity criterion a philosopher offers us is such that if that criterion were true, then it is obscure what people could possibly be, then isn't that a count against his or her criterion?" (Thomson: 157).
One can attempt to salvage the psychological criteria by adding a 'no competitors' clause:
P1 is identical to P2 (i) iff P1 at t is psychologically connected with P2 at t* and (ii) iff P1 is not psychologically connected to P3 at t* (in other words, there are no competitors with P2).
However, as Judith Thomson argues, the no competitors clause makes personal identity hinge on a matter that should be irrelevant to personal identity. If an exact replica of Fred's brain is placed inside Bob1's head (with the original brain being destroyed) and Bob1 wakes up acting like Fred and remembering most everything that Fred had experienced, we would likely be willing to say that Bob1 is Fred -- in other words, Fred survived the surgery. If, however, Bob1 and Bob2 receive replicated Fred-brains and each survives the surgery and each is psychologically connected to Fred, then they are not identical to Fred, or it is indeterminate whether they are identical to Fred, according to the no competitors clause. But surely, argues Thomson, if psychological connectedness is a good mark of personal identity, the survival of Fred and the identity of the post-surgery survivor(s) should not hinge on such peculiar circumstances as whether Bob2 (or Bob1) survives the surgery or whether two replicas of Fred's brain are created. Since it does, the no-competitors clause cannot salvage psychological criteria and, therefore, psychological connectedness is not a good criteria for personal identity [3].
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Footnotes:
[1] Thomson, Jidith J. "People and Their Bodies." Contemporary Debates in Metaphysics. Ed. Theodore Sider, John Hawthorne, and Dean Zimmerman. Oxford: Blackewell, 1997. 160. Print.
[2] The narrow psychological criterion states that both psychological connectedness and having the same brain are marks of personal identity. Thomson argues that it should be irrelevant whether the same lump of neurons and matter are preserved, so long as "psychological transplanting" occurs (Thomson: 159).
[3] Thomson writes, "...if the identity criterion a philosopher offers us is such that if that criterion were true, then it is obscure what people could possibly be, then isn't that a count against his or her criterion?" (Thomson: 157).
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