Locke
First, a little bit about Locke. It should be pretty easy to find summaries of Locke’s views on personal identity using a search engine. I provide a couple of links to videos above. Locke’s view is simple: what makes you who you are is your consciousness, and so if you can now remember an event in the past, say a year ago, then you are the same person as the person who had that experience. Locke does not endorse any theory of consciousness, since he thinks it is mysterious. He does not understand how a brain could create consciousness, but equally he does not understand how an immaterial soul could do it. So he does not endorse a soul theory or a brain theory of personal identity. His view is, however consciousness works, it is consciousness that makes us who we are.
Locke’s theory has plenty of intuitive appeal. But it also has lots of problems. First, there are details that need filling out. What does he want to say about:
• The time before we had consciousness, whenever that was. Say we get it at 6 months old as an embryo in the womb. Is that when we started existing? Not at birth and not at conception?
• Since we can’t remember our first consciousness, (at least most of us cannot — although a few claim they can remember being in the womb) does that mean that we are not the same person as we were in the womb? (It is hard to even state the question without some kind of paradox.)
• What about episodes of memory loss? If I get a knock on the head and lose memories of the past week, then am I the same person as the person who occupied my body during that week? If not, then who was in my body?
• If we get the technological possibility of copying the parts of my brain structure that make up my memory for some event E, and also get the technology to put that brain structure in someone else’s brain, so they can now “remember” event E, does that mean that they now become the same person as me? That’s what it seems his theory implies. If we can put the memory in 1000 people, then do I become the same person as those 1000 people? Could that make any logical sense?
These questions might be answerable, but it will mean making Locke’s theory much more precise. It seems that however we make the theory more precise, we will end up with some strange consequences that go against our “common sense” about personal identity.
Swinburne
Swinburne takes a very different view, arguing that we are essentially non-physical entities, and we have souls that are our essential being. This is obviously close to a religious view, but he argues for it using careful argument rather than appeals to faith or reference to sacred texts. His main idea is that physicalism cannot explain our consciousness, and the only way we can explain consciousness is to suppose that there must be a spirit that enables our minds to operate. He also adopts the view that that spirit is us — the human body is more like a temporary location where the spirit lives for a while. His latest book is Are We Bodies or Souls?.Obviously his answer is “souls”. (Some might say “neither.”) In the extract we have in the book he adopts arguments very similar to those of Descartes in the Meditations. The basic idea is that I am essentially a thinking thing, because I can imagine myself without a body but I can’t imagine myself without a mind. He concludes that we are essentially minds, and that we are not essentially bodies. This sort of argument has been analyzed a great deal, and can be doubted at many stages.