This is the 57th post in my Theories of Knowledge and Reality series. The last post concluded discussing the psychological account of personal identity. This post moves on to the bodily account.
According to the dualist account of personal identity, being the same person is having the same immaterial mind or soul. According to the psychological account of personal identity, being the same person is having a continuation of the same set of psychological properties such as memories, desires, beliefs, personality traits, moral character, and so on. The main contender to those two approaches would be biological accounts, which base personal identity in some biological facts. The most common versions of biological accounts are the bodily account and the brain account. The bodily account takes someone to be the same person just in case they have same continuing body. Sometimes it's put in terms of whether there is a continuing organism.
The central intuition behind the bodily or organism view is that we are most fundamentally biological organisms. That's what it is to be a human being. So it would make sense if the criteria for remaining the same human being had to do with being the same biological organism, i.e. continuing to exist via having the same living body.
You get a counterintuitive result from the bodily view. Suppose we develop the technology to remove my brain and put it in your body. I think most people would then say I switched bodies, an intuition that favors the brain view. On the bodily view, you get the very weird result that I remain in my original body. If no brain is put in, then I might simply be a human vegetable. If your brain is put in my body, then I'd think I'm you and now would have all your memories, personality, moral beliefs, and character traits. But there's you, going around in your own body, thinking you're me and having my traits. According to the bodily view, it would still be you in your original body acting as me and me in my original body acting as you.
But Eric Olson gives a difficult argument to resist for a bodily view:
1. I could have been born without a
2. If something could have been different about me, then it's not essential to me.
3. Therefore, my brain isn't essential to me, to my being me. So I could continue to exist without my brain.
The first premise seems intuitively true. I could have had the condition of anencephaly, in which case I would have been born with no brain, just a brain stem, and I wouldn't have lived long.
The second premise seems obvious at first glance. An essential property is defined as something without which you wouldn't have been you. How could you gain and lose essential properties, then? It should be the sort of thing you would never be able to gain or lose.
I can think of three different ways someone might try to resist this argument.
dualism is true, there actually isn't anything disturbing about this argument.
If dualism is true, then our brains aren't essential to who we are. That's the
point of dualism, in fact. Descartes thought it was possible to exist without
your body at all, including your brain. So dualists might even accept the
argument as it stands without accepting Olson's organism view of what we
a biological view that considers the brain to be essential to who we are is
correct, then the first premise is false. The anencephalic baby that might have
resulted from the same egg and sperm I came from wouldn't have been me, because it would have had no brain at all and thus not my brain. So the argument begs the question against that view by assuming a premise that
no one holding that view would grant.
the psychological view is correct, then the second premise is false. I could
have been born without a brain, and at that point my brain wasn't
essential to me, but now it is because now my psychological properties
are present. This requires that what's necessary for you to be you can
change with time. Many philosophers would frown at this, since the idea was to
find what's central to your being you that doesn't change over time. But this
is a possible view. You could never lose an essential property. You'd stop
being you (and thus stop existing). But you can gain essential properties. Once
you have them, they're essential, but they weren't essential before you had
So it seems as if all three rival views have a response to the argument. That doesn't mean the argument is unsound. It just means the alternative views shouldn't accept the premises, so a careful proponent of the alternative views would be unconvinced. But you might not want to reject either premise except to defend a view you already hold, and so the argument might still convince someone who is inclined to accept the premises. Also, the notion that we're simply biological organisms does appeal to a lot of people, and that's the basic intuition behind this view, even if the view's implications in brain transplant cases and human vegetable cases might conflict with other intuitions some people have.
It's not clear that the arguments here are all that decisive, therefore. But it is clear that, though we have some intuitions that conflict with a bodily view, we also have some that conflict with it.
In the next post
, I'll look a little more closely at the brain view.