Is the idea of personal identity exhausted by the views of physicalism and dualism?

There are more things in heaven and earth than are dreamt of in our philosophy.

Personal identity has been proposed as a concept to account for the nature of the identity of a person over time, but apart from math, terms like identity lack clear definition, and a term like person has no place in an advanced science. It is not, nor can it be, a natural kind.

Nonetheless, let's tentatively regard the term personal identity as an idea, a philosopher's idea, one that is best to eschew, but which meanwhile philosophers have used as an umbrella term to be able to talk about a loose set of related ideas that actually do have a bearing on practical matters. Follow me down this rabbit hole.

We ask if there is more to our existence than this, our three score years and ten, and of course we do not know, but erring on the conservative side, many of us conclude that since there is no evidence of life after death that there is no life after death. Still others, for various reasons (no doubt optimism being one driver), wish to believe that there is life after death. In order to conclude as much, such people often posit souls, something immaterial which we are said to be really or essentially.

Does one have to posit the existence of a soul in order to believe in life after death? I don't think so. Not enough someone believes in reincarnation, that is. What do I mean? How would reincarnation work without souls? Well, it could be the case that the specific physical constitution that gives me this first-personal feeling of what of what's like to be could be or could have been constituted or reconstituted functionally so that this exact same first-personal feeling is replicated in another being. There would be, then, something of what it feels like to be me now and also at a former or later time.

Now you may ask how could an entirely different human body generate the same first-personal feeling? The answer to that question would be just as mysterious, I assume, as it is to account for something as immaterial as a soul. And of course there's no evidence for it.

Also, you know, it would be a very funny cosmic irony for the universe to replicate beings that have identical first-person feelings and yet these beings would have no idea that they have been here before or might be here again. You could easily see how the entertaining of such an idea might seem like a kind of hell, and it would help make sense of the Buddhist idea about trying to break this cycle of birth, death, and rebirth.

But as I said, there's no evidence for these extravagant claims. In the interests of rationality, therefore, it's best to err on the side that all there is is this three score years and ten. However, I wouldn't want to rule out irrational and yet pragmatic reasons for why one would want to believe in life after death. For some who have lost loved ones, the idea can be a comfort. And for those who are about to die, the idea can be a comfort. It's not always best to disabuse people of their irrational beliefs, ourselves included.

Thales

There's an urban legend that says that Thales was such the absentminded philosopher that one night while he was staring at the stars, he tripped and fell into a well, sending a nearby slave girl into hysterical laughter. And yet this was the same man who predicted not only a solar eclipse but a boom year for the olive harvest. With respect to that harvest, he was so enterprising that he bought up all the olive presses in the area so that he would have a monopoly on olive oil. And he did it.

Thales was born in 626 BCE and died in 548 at age 78. He spent most of his professional life as a statesman in a town in Asia Minor called Miletus, famous for its trade in wool, and rich. Fortunately for history, this world gave Thales enough time to philosophize. Unfortunately for us, we know very little of his actual philosophy, and this for the first known philosopher.

Here are two pieces of Thales' philosophy we know about. One is that he believed water was fundamental for life. This view anticipates our contemporary view of water's necessity for life. We don't know how Thales arrived at his conclusion. Perhaps he observed his very own civilization's proximity to water or people's reliance on potable water, or perhaps he watched the growth of plants and crops and thought that their growth generalized to the rest of life. We just don't know.

But we do know about this other piece of philosophy, and this through Aristotle. Thales noticed the effects of magnetism and concluded that there must be some particles within the objects that created these effects of attraction and repulsion. He called these souls. He posited that all things were full of souls. This isn't exactly modern particle theory or our understanding of force fields but this careful observation, using the vocabulary of his day, surely presages modern scientific conceptions of how subatomic particles operate in force fields.