What is it to be the same person over time?

Transcription

1 Personal Identity This book contains notes on John Locke's view of personal identity, as well as Daniel Dennett's essay, which reconsiders and challenges that view. Dr. Gina Calderone Table of contents What is it to be the same person over time? Are you essentially a soul? Are you just a living human being? It is consciousness that makes you, you. What is necessary for consciousness and memory? Are you your brain? Is your brain even necessary? Duplication What is it to be the same person over time? Please read the excerpt from John Locke, An Essay Concerning Human Understanding, Book 2: Of Ideas, Chapter 27: Of Identity and Diversity. The philosophical question of personal identity arises from a little conundrum: we know that, as a person moves through life, just about every aspect of that person changes in one way or another. You started out small with an underdeveloped brain, your body grew, your physical characteristics changed, you ve lost (and gained) parts, you ve acquired beliefs and values and personality traits some of which continue to evolve in response to your experiences. It s hard, in fact, to think of anything that doesn t change to some degree as one ages; and yet, it seems true that, for example, I am the same person, who, some years ago, was 2 feet tall and believed in Santa Claus, even though I am neither 2 feet tall nor believe in Santa Claus. So the question of personal identity is about how to make sense of being the same person throughout all the changes. One answer naturally presents itself. Many people believe that a person is essentially an immaterial soul, which remains the same throughout one s life, possibly into the next. We might put this idea

2 as follows: The Same Soul Theory: x=y if and only if x and y have the same soul. That is, at any given point on the timeline of one s life, we might pick out and name the person at that time. We can use a name, a nickname, or a variable like x, y, or z. Say that x picks out you when you were 4 years old and y picks out you today. This theory then says that x is the same person as y just in case x and y have the same soul. While lots of things have changed about you during all that time, your soul has remained one and the same. Are you essentially a soul? The Same Soul Theory is attractive since it also makes sense of the idea of surviving one s death, but it has problems, not the least of which is that the soul, being immaterial, lacks a principle of individuation. That is, one is hard-pressed to say when x is the same soul as y without drawing on some other individuating characteristic, like similarity of body, or similarity of psychological characteristics. As Locke puts the problem, how can one say when one has the same soul as, for example, Socrates, or for that matter, Nestor? Let any one reflect upon himself, and conclude that he has in himself an immaterial spirit, which is that which thinks in him, and, in the constant change of his body keeps him the same: and is that which he calls himself: let him also suppose it to be the same soul that was in Nestor or Thersites, at the siege of Troy, (for souls being, as far as we know anything of them, in their nature indifferent to any parcel of matter, the supposition has no apparent absurdity in it), which it may have been, as well as it is now the soul of any other man: but he now having no consciousness of any of the actions either of Nestor or Thersites, does or can he conceive himself the

3 same person with either of them? Can he be concerned in either of their actions? attribute them to himself, or think them his own, more than the actions of any other men that ever existed? So that this consciousness, not reaching to any of the actions of either of those men, he is no more one self with either of them than if the soul or immaterial spirit that now informs him had been created, and began to exist, when it began to inform his present body; though it were never so true, that the same spirit that informed Nestor's or Thersites' body were numerically the same that now informs his. For this would no more make him the same person with Nestor, than if some of the particles of matter that were once a part of Nestor were now a part of this man; the same immaterial substance, without the same consciousness, no more making the same person, by being united to any body, than the same particle of matter, without consciousness, united to any body, makes the same person. But let him once find himself conscious of any of the actions of Nestor, he then finds himself the same person with Nestor. According to Locke, once the connection of consciousness is established, it becomes clear that the soul is unnecessary to personal identity after all: so that whatever has the consciousness of present and past actions, is the same person to whom they both belong. Are you just a living human being? Why not suppose that sameness of living body (whatever its material constitution) is necessary and sufficient for sameness of person? Bodily Continuity Theory: x=y if and only if x and y belong to one continuous living body. This would mean that once this body dies, that s the end of me, which certainly seems like a real possibility. This, thinks Locke, does account for the idea of same man, which has as its principle of individuation the same principle as other animals: An animal is a living organized body; and

4 consequently the same animal, as we have observed, is the same continued life communicated to different particles of matter, as they happen successively to be united to that organized living body. And whatever is talked of other definitions, ingenious observation puts it past doubt, that the idea in our minds, of which the sound man in our mouths is the sign, is nothing else but of an animal of such a certain form. Since I think I may be confident, that, whoever should see a creature of his own shape or make, though it had no more reason all its life than a cat or a parrot, would call him still a man; or whoever should hear a cat or a parrot discourse, reason, and philosophize, would call or think it nothing but a cat or a parrot; and say, the one was a dull irrational man, and the other a very intelligent rational parrot. In other words, a parrot is still a parrot, however intelligent, and a man is still a man, however stupid; each in virtue of being a continuous live being whose material is organized in a particular parrot-like or man-like way. But when it comes to the meaning of person, that concept involves a thinking intelligent being, that has reason and reflection, and can consider itself as itself, the same thinking thing, in different times and places. Thus, the concept of same person is essentially tied to the way one identifies the self on different occasions. It is consciousness that makes you you. So how does a person identify herself, time after time? Locke writes: When we see, hear, smell, taste, feel, meditate, or will anything, we know that we do so. Thus it is always as to our present sensations and perceptions: and by this every one is to himself that which he calls self:- it not being considered, in this case, whether the same self be continued in the same or diverse substances. For, since consciousness always accompanies thinking, and it is that which makes every one to be what he calls self, and thereby distinguishes himself from all other thinking things,

5 in this alone consists personal identity, i.e. the sameness of a rational being: and as far as this consciousness can be extended backwards to any past action or thought, so far reaches the identity of that person; it is the same self now it was then; and it is by the same self with this present one that now reflects on it, that that action was done. In other words, your consciousness makes you the person you are now, and your memories connect your conscious experiences over spans of time it is this ability to remember that makes you the same person over time. So Locke's theory might be characterized as follows: Psychological Continuity Theory: x=y if and only if y contains memories of x. What is necessary for consciousness and memory? So what is it that remembers, if not necessarily a particular body or soul? This is an especially important question if we wish to make sense of the idea of same-person/different-man, as must be the case if you (the person) have existed before as some distinct man, or will exist again after the loss of this living body. For Locke, the thinking substance was likely an immaterial thing, though the matter of personal identity was tied to the thinking rather than the substance that does it. As long as consciousness is preserved, he argued, the person is preserved. More recently, a kind of scientific materialism emerged as the scientifically respectable way of accounting for all mental phenomena, including consciousness. For the materialist, all things are physical things, explainable in terms of physical stuff and laws, including the mind, and indeed, the person. Materialists sympathetic with Locke s arguments would similarly identify the person with his mind, but take the further step of identifying the mind with the brain. Brain science does suggest, rather forcefully, that memories are made and stored in the brain. Suppose then that a duplicate of your brain could be made that preserves consciousness, both present and potential (as when one recalls past moments of consciousness). This kind of duplication preserves the possibility of you after death, either when, say, God duplicates your brain, or when, alternatively, some future scientist does it. But this idea, when carefully

6 considered, leads to other difficulties for our notion of same-self. Are you your brain? Please read Where Am I, by Daniel Dennett (1978). In Daniel Dennett s Where Am I, Dennett imagines a scenario in which his brain has been removed and placed in a vat with radio transmitters communicating signals between his functioning brain and his functioning body. His mission involves a hazardous trip for his body, while his brain, via radio signals to and from his body, communicates from its safe place in the vat. Three possibilities present themselves: 1. The person goes where his body goes; 2. The person goes where his brain goes; or 3. The person is wherever he thinks he is. Let s put all of this in first-person perspective. When both brain and body exist simultaneously, communicating via nerves or radio signals, my consciousness appears to align with 1: I seem to be where my body is, regardless of where my brain is. That is, I feel like I m looking out my eyes, even if my brain happens to be two time zones to the east. Moreover, no matter how hard I try, it s nearly impossible to think my way back to my brain in the vat. This seems to count against 3. But if my body is destroyed in the mission (as Dennett s is), it is clear that I have survived, able to recall the event of losing all connection with my body. This points to the truth of 2, rather than 1. Is your brain even necessary? Dennett s story continues with his brain being hooked up (again via radio signals) to a new body. Dennett's brain still recalls Dennett s past so the new body, while perhaps a bit unsettling, seems unproblematic to the preservation of Dennett s identity. Again, this seems to provide further evidence for the truth of 2: that you go where your brain goes. But here s the rub: Locke and Dennett are supposing that it s consciousness that picks out the self, wherever it is and regardless of what it's made of. So consciousness is taken to be multiply

7 realizable. Descartes thought souls had it, materialist philosophers think brains have it, but maybe other kinds of things can have it too like machines. Duplication Dennett imagines that his cadre of brilliant scientistcaretakers had, as he puts it, constructed a computer duplicate of my brain, reproducing both the complete information-processing structure and the computational speed of my brain in a giant computer program. Only one of these structures either the computer simulation or the detached brain is at any given time operating (or communicating with) Dennett s new body, and as long as the two are in sync, Dennett can t tell the difference. Nevertheless, in such a scenario, there are now two things-- a computer simulation and a detached brain--that can remember being Dennett. Are they both Dennett? This should be impossible: The computer simulation (C) is not the brain (B), so how can both the computer simulation and the brain be Dennett (D)? If B=D, and C=D, then B=C; but B is not C, so which one, if either, is D? The problem is made especially vivid when the computer simulation and the brain go out of sync. At that point, the simulation and the brain have different thoughts, and yet each remembers Dennett s past. This strange possibility seems to count against Locke s theory of personal identity that memory of past consciousness is sufficient for being the same person over time. You're the philosopher: Suppose you had a chance at immortality but one that didn't preserve every aspect of who you are right now. Would you take it? What features of you must be preserved for you to consent, if at all?