Is psychology enough to preserve one’s personal identity? I have been reading through the different notions of personal identity, and I am not convinced the psychological view resolves the issue. The psychological view asserts that what secures a person’s identity over time is something within their mind, i.e. memories, consciousness, beliefs, etc. For example, the reason I am the same person as I was when I was ten is due to the fact that I remember the time when I was ten and certain events occurred.
Eric Olson presents a thought experiment in his book The Human Animal, which brings out a potential incongruity for the psychological view. Suppose there was a man A who had his cerebrum transplanted into the skull of another man B. After the operation, the A-body dies; the memories of A now reside in the brain that is in the B-body. Is it safe to say that A merely switched bodies, meaning A now lives in the B-body (aside from the bodily or material difference, it is the same person)? This example would be perfectly aligned with a view that something in psychology preserves identity.
Let’s take it further. Suppose that the A-body survives this operation. Who is A? He must be the vegetative A-body or the B-body with A’s memories or both or neither. Many might be inclined to support the initial example because it seems plausible that one’s memories could be transplanted into another body, especially if the original body was no longer functioning. But what happens when there are two survivors with some kind of basis for claiming to be A [we are ignoring that B had a mind at some point, but that’s another problem altogether]. Does A survive in two bodies or one? Well, for a consistent supporter of the psychological approach A would survive in B’s body and the A-body is no longer a person.
Can this example be pushed even further? Suppose A’s cerebrum gets cut in half and transplanted into two different bodies. Olson refers to these beings as Lefty and Righty. Presumably, they would each have A’s memories, along with other psychological features. This example leads to the primary incongruity of the psychological approach, which seemed capable of handling the previous examples. Does A now exist as two people, since the cerebrum was cut and transplanted into two different bodies? If yes, when Lefty goes to Rwanda and Righty goes to Hungary, does A go to Rwanda or Hungary or both? It seems reasonable to assert that A cannot go to both places. One could only decide arbitrarily that Lefty is A, not righty, or vice versa. If something psychological is the only element that preserves identity, then one would have to claim that A is identified with both Lefty and Righty. Wouldn’t one?
I thought this was an interesting presentation of why Olson does not adhere to the psychological approach. Olson claims that one’s biology alone is what preserves personal identity. The biological view is in the minority, but in some ways, it makes more sense to me at the moment. Unfortunately, it will not be expounded in this entry. Suffice it to say, I believe that an aspect of psychology might be important for personal identity, but I don’t think it encompasses it. I think there must be something more than just a psychological component.
I agree with you and Olson that psychology is at the very least insufficient to preserve personal identity, partly due to the thought experiment, and partly due to the fact that it assumes that personhood is accidental to human life.
However I’m not quite clear how biology can accomplish this? Every seven years, nearly all the cells in one’s body are replaced by newer cells, yet we don’t assume that there is a new biological being.
How does Olson approach this? Is it due to DNA? If due to DNA, then clones would be identical to their ‘parent.’ Is it the intrinsic directedness of an organism (an organism grows to be a certain sort of thing- invoking final causality)?
I’m not sure what Olson would do with cell replacement. Of course, this problem goes all the way back to Theseus’ ship. My guess is that since all the cells are not replaced at one time, the new ones have a chance to assimilate into the human animal one at a time. Basically, the cells, even new ones, are not part of a heap [as Aristotle calls it], but they are part of a unified whole. The unity of the being causes the cells to part of the person’s identity, rather than something different.
On the other hand, maybe there is a sort of functional explanation. A human animal is just the sort of thing that changes its cell every 7 years.
These are my first atempts at answering your queries, and they are likely insufficient.
My first thoughts mirror Davis’. If personal identity is biological then I am not the same person I was when I was ten. I guess my question is what does “assimilation” mean in this context. Does it mean that since the new cells have a chance to interact with previously existing cells that the new cells are not part of the person?
It seems to me that maybe the answer isn’t psychological or biological but metaphysical. I’m not simply talking about the form of human-ness but some individual metaphysical reality that unifies a person and allows for continued existence though the being experiences physical change.
I might be making an unnecessary distinction between metaphysics and psychology but even though both of these disciplines deal with the same subject matter than approach them in different ways and for different ends.
Then again…the Mormons could be right.
By ‘assimilation’, I meant that the new cells become a part of the human animal at some point in time, perhaps even instantly. If we replace one plank of wood on a boat, then the new plank becomes a part of the overall ship. This ‘assimilation’ seems to follow if we eventually replace all the planks.
I do agree that the problem is metaphysical in nature, and I think the animal view is lacking in some areas. But I tend to think the animal view has more merit than people have wanted to grant it.