24.00: Problems of Philosophy Prof. Sally Haslanger October 15, 2001 Personal Identity I There are several questions that might arise concerning personal identity. When we ask "Who am I?" we might be wondering about what "makes us tick", what we ultimately value, what matters to us. We might also be asking what sort of being we are, what our possibilities are, under what conditions "I" would continue to exist. We'll begin our discussion of personal identity with the latter set of questions. Consider a parallel set of questions: (Id) Under what conditions are baseball-events events in the same game? E.g., under what conditions are a particular batter batting and a particular runner running parts of the same game? Break (I) into two questions. First, the question of synchronic identity: (SI) Under what conditions are simultaneous baseball-events events in the same game? Let a baseball "stage" consist of all the events at a given time that are part of a single game. Then we can formulate the question of diachronic identity as follows: (DI) Under what conditions are two baseball stages stages in the same game? E.g., what makes the beginning of the third inning and the end of the eighth inning stages of the very same baseball game? Restate the questions for persons: Synchronic identity: under what conditions are two simultaneous person-events events in the life of the same person? Diachronic identity: under what conditions are two person-stages stages in the life of a single person. In particular, what makes a particular person-stage a continuation of me as I am right now? Synchronic unity relation: the relation that unites simultaneous person-events into a stage of a single person. Diachronic unity relation: the relation that unites person-stages into a single temporally-extended person. Perry Dialogue, First Night: 1. (Weirob) Is survival of death possible? ? What we want is survival of me (not the molecules of my body...). ? What survives must do justice to possibility of anticipation and memory. 2. (Miller) Postulation of soul. Soul criterion: x is the same person as y iff x and y have the same soul. ? What is a soul? The subject of consciousness? A spiritual/disembodied self? The ghost in the machine? 3. (Weirob) Practical applicability condition on adequate response: ? An adequate account of the survival/identity of persons must also be able to justify our practices of recognizing and identifying each other. 4. (Weirob) The soul not a good basis for recognition. ? We can recognize each othersí bodies, but not each othersí souls. 5. (Miller) Body-soul correlations provide a basis for recognition. ? We do observe the soul indirectly by observing the behavior of each others' bodies. 6. (Weirob) But how do you know that there is a body-soul correlation? By observation? ? Chocolate example shows that correlation between body and soul untestable; if not testable, it must just be a matter of faith. 7. (Miller) Personality-Soul correlations provide a basis for body-soul correlations. ? If the soul is the subject of mental states, the soul must be what explains the pattern of mental states, i.e., it must be what provides us with our personality or character. So there must be a correlation between soul and personality. 8. (Weirob) But even if soul does account for personality, thereís no reason that one must have the same soul to exhibit the same personality. ? We can't infer from sameness/similarity of personality to sameness/similarity of soul. ? River analogy: rivers have the same appearance even though the water molecules are constantly changing; better example: Martians/God/mad scientist could make a duplicate of you with the same personality, but without the same soul. ? [Also, don't people sometimes undergo changes in their personality, e.g., after a conversion, a tragic experience, falling in love, etc.?] 9. (Miller) But maybe the relevant correlations must be established by 1st person observations. ? I know of myself that there is a body-personality-soul correlation. 10. (Weirob) But how do you know that even in your own case? ? All that you introspect is thoughts and feelings, but isnít this compatible with a sequence of souls passing through? How do you know that God doesnít give your body a new soul each morning? How would you tell if when you woke up there was a new soul responsible for your thoughts, or just the old one? 11. (Weirob) Does the postulation of soul really help? Doesnít it push the question back? ? E.g., suppose I say that a flower blooming in my garden is the same one that was blooming yesterday; someone asks: on what basis do you say that? I say that it has the same flower-spirit as the previous one. Doesnít the question arise: what are the identity conditions for flower spirits? What does it take for a flower-spirit to continue to exist? 12. Gretchenís bodily solution: ? Do I doubt my own soul? Not in the sense of doubting that Iím conscious. But my consciousness is a property of a body, and that body is me. But if I am my body, then the destruction of my body is the destruction of me. So: Body criterion: x is the same person as y iff x and y have the same living human body. In other words: Person-stage x is part of the same person as person-stage y iff x and y are person stages linked by bodily continuity (where bodily continuity is understood in terms of the continuity of a living human body).