From guest blogger, Tim.
I’ve been thinking about personal identity and how we determine the continuity of an individual person’s existence. The mind theory and the body theory seem unsatisfactory to me.
One interpretation of the body theory claims that I am the same person over time if my body is the same body over time. But our bodies change. The cells that make up my body are constantly changing. That the body changes doesn’t show enough to dismiss the theory however. The body theorist could claim that the body only has to be numerically identical. Certain thought experiments show that the body theory is inconclusive, at best. Consider the teleporter example, in which my body is teleported between two points. As the process goes, my body is scanned and destroyed at point A. Then my body is reconstructed exactly at point B. Can we claim that, for the brief period after my body is destroyed and before it is reconstructed, that I cease to exist?
The mind theory encounters similar problems. John Locke holds a view that personal continuity is dependent on memory. I am the same person over time if I can reflect on these memories. An objection to this and broader mind theories when considering a person with amnesia. Assume that the person has no previous memories and none of their previous thoughts persist. The mind theorist would have to say that the person prior to developing the amnesia no longer exists and the person after just pops into to existence. If the amnesia is reversed, the original person would come back into existence.
These are just a few objections to these theories, but I think they highlight some concerns one might have with the theories. If we find these theories unsatisfactory, then we only have two options. We can accept that there is no personal continuity and that there is no self, or we must define personal identity in a different way. This could be a soul theory or a theory that combines the mind and body theories.