Personal Identity

From Guest Blogger, Shiying.

Personal identity is a field of philosophy that studies the definition of persons and under what conditions persons persist. There are three main accounts of personal identity. The psychological approach claims that a person at a time t1 persists to be the same person at another time t2 if and only if the person at t2 is psychologically continuous with the person at t1. The biological accounts say that bodily or physical continuity is a necessary and sufficient condition for personal identity. The soul theorists maintain that personal identity is defined by soul. There is a large amount of literature about the psychological and biological accounts of personal identity. I will not discuss them in detail here.

But both psychological and biological approach face various objections. I have always had a hard time deciding which of these two theories are more plausible to me since I first learned about these theories. I have also been thinking about a possibility to combine these two views. If we combine the two views brutally and require both psychological and biological continuity for personal identity, we are going to face the objections for both theories. However, maybe the problem exists in our attempt to find necessary and sufficient conditions for personal identity. If we consider Alston’s examples of defining “poem” and “religion”, we may be able to use a similar approach to define personal identity. Personal identity is not defined by the strict criterion of psychological or biological continuity. Personal identity requires a certain combination of psychological and biological continuities each to a certain degree. A large amount of psychological continuity may be able to compensate a small amount of biological continuity, and vice versa. There may be many possible variants of this view. One can say that each component needs to reach a substantial degree in order for personal identity to persist. I can also anticipate many disputes about the weight of each component and/or what counts as substantial for each component. However, instead of adopting a singular account of personal identity, this pluralist account may help us define and understand personal identity better. 

Some Thoughts About Personal Identity

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.