Hello, My name is Kyle, I'm a physics student. I have zero training in philosophy, save for an introductory philosophy course in my freshman year. I've been thinking about something quite frequently, and would like to hear an opinion from somebody who is knowledgable in the subject; The mind and the ego is a construct of the brain( at least as far as I know), and it's experiences. And I think it's fair to say that the brain is a clever organization of atoms, in what is essentially a computer. It has memories, which I think forms the ego, in a seemingly contiguous storyline. The hardware of the brain is however constantly changing, with atoms being lost and gained, through cell death, reproduction, respiration, and other biochemical functions, and yet our subjective experience remains. Suppose this effect is recreated in hypothetical setting where it is possible to create an exact replica of a person(A) to an artificially constructed person (b). Now, the copy is an exact replica, with every electrochemical charge in the brain at their respective locations. The copy(b) would be finishing the thought that person (a) was thinking at the start of the process, with every memory in place. Suppose the process kills person (a) leaving only person (b) who feels as if nothing happened. This process is analogous to the natural biochemical exchange discussed before. This thought experiment leaves me a bit puzzled as to the implications on the ego and subjective experience. If anyone could derive a conclusion, I would love to hear.

Good for you! You've stumbled on a central question in contemporary philosophy, and the thought experiment you offer is very similar to ones proposed by (among others) philosopher Derek Parfit, whose views on this question are much-discussed. The problem is what makes someone the same person over time. Put another way, what makes a person at one time the same person as a person at another time? The standard term for the bundle of questions here is the problem of personal identity. Usually, having the same body/brain is enough; your example points out that this might not be the only thing that matters. In particular, someone might think that continuity of consciousness is what's needed. The 17th-century philosopher John Locke held a view like this.

As you'd expect, different philosophers have come to different conclusions. Parfit thinks that identity is shallow and not what we really care about. On Parfit's view, psychological continuity is what matters, and he would say that in the case you've offered, we could say that A has survived; the copy, for all purposes that matter, is A. But Parfit thinks that the "is" here doesn't matter as much as we might think. Suppose the process doesn't destroy the original A-body. In that case, Parfit would say that the person in the original A-body and the copy are both psychologically continuous with the earlier stages of person A. A's consciousness has, n effect, divided. On Parfit's view the question of which person is "really" A is a shallow one. We could say that nothing have equal claim to being A. But they can't both be A, because two people can't be one person. So on Parfit's view, neither of them is A. Nonetheless, since both of them carry A's consciousness forward, what's happened is at least as good as ordinary survival from A's point of view.

My own view is that we understand all this less well than many philosophers tend to think, but that's neither here nor there. One place to start exploring the question further is by reading the article on personal identity in the Stanford Encyclopedia of Philosophy. You can find that HERE

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