Who is this strange person “Me”? Obviously I am “Me”, but you claim that “Me” is you. How could that be? And when you say “You”, you mean me! You are you and I am me and that’s an end of it! It is absurd for you to claim to me when, patently, you are you.
Have you (yes, YOU! I know that I have!) ever read science fiction? An SF story might revolve around a device, maybe invented by Professor MacGuffin, which allow the actors in the drama to move instantly from one place to another. The ‘transporter’ may be a simple tool to place the actors in a situation from which they have to extract themselves (as in the Startrek TV series and movies), or a device central to the plot, such as the machine in movie “The Fly” (‘Help me! Help me!)
Sometimes, for plot reasons, the device may malfunction and instead of transporting the person from A to B, it essentially copies the person so that he exists at both A and B. (Both you and I agree that he is ‘he’ or she is ‘she’, don’t we? I’m glad that that is sorted out, at least).
So if I walk into the transporter at A, I walk out of it at B, don’t I? But the person at A claims to be me and to have walked into the transporter at A and walked out of it at A, thinking that it hadn’t worked. He, (obviously “he”, since he isn’t me and he isn’t you), also claims that my car, my dog, my wife, are all his, and they are because he was me when he walked into the transporter. Obviously “his”, since they aren’t yours and they aren’t mine. Hang on a minute! They ARE all mine! This is getting tricky.
So which of us is me, and which isn’t? Which is ‘him’? Which of us gets my things? Do we get half each? It’s a puzzle.
Even when we exclude transporters as ‘impossible’ (but who would be so bold as to rule them out entirely), even then, there are other ‘mes’ to consider. There’s the ‘me’ from five minutes ago. The ‘me’ who had yet to write this sentence, who didn’t even have this sentence in mind, in fact. There’s the ‘me’ of five minutes in the future, who know what the next sentence brings. (I can’t even guess what it will bring). Are they the same ‘me’? Well the future me knows things that I don’t, and I know things that the past me doesn’t (yet) know.
It gets worse as you consider moments further from the ‘now’. When I was at school, I was not the same person as I am now – I have years of experiences that the schoolboy had not yet had. I’ve no idea what will happen in the future, but the future me does. So are the future ‘me’ and the past ‘me’ really me? They are different from me in terms of their memories and experiences. They have different bodies, maybe sporting scars that I don’t have or vice versa.
Most people would think that they are ‘me’, in spite of these differences. There is a continuity of memory, a thread of remembrance, that joins all these ‘mes’ in a continuous thread of experience. But if you take two widely time separated ‘mes’ they in fact have little in common. The schoolboy ‘me’ has not learned things that the future ‘me’ knows and the future ‘me’ may have forgotten much of what they schoolboy has experienced.
From some points of view they are very much not the same person. It reminds me of the saying by Heraclitus “No man ever steps in the same river twice, for it’s not the same river and he’s not the same man”. While it may seem to me that the memories I have connect me to the school boy that I was, as I can work backwards down the stream of memories and say ‘I was that school boy’, that same stream of memories makes me different from him. Even in my own mind I think of the school boy as ‘him’ and refer to him as ‘myself, X years ago’.
It’s not uncommon for people to say things like “If I hadn’t done so-and-so, something else would have happened”. “If I hadn’t read that book in school, I wouldn’t have chosen to study history at university…” There is a probabilistic component to personality. If things had been otherwise I would be a different person, probably living in a different country, and certainly with different memories and desires. “I’m glad I went to the moon, even though it meant giving up that opportunity to live and work in Antarctica”. Well, something like that!
So this mysterious ‘me’ lives only in the present, and is different to all other ‘mes’ through time. Yet this ‘me’ is singular, for I am the only ‘me’, and your claim to be ‘me’ is patently false. This ‘me’ is not any of the possible ‘mes’ that could have been, had things been different. This ‘me’ is not the same as the ‘mes’ that have been and the ‘mes’ that will be, even considering the chain of memory that connects us. The ‘me’ that goes through a transporter device is not the ‘me’ that stepped into it, as the new ‘me’ is composed of different atoms (presumably, ducking a few questions), even though the transported ‘me’ feels otherwise. But then again neither is the ‘me’ who stayed since time separates him from the ‘me’ that entered the transporter, even if it is only seconds.
The more that I consider ‘me’, the stranger ‘me’ (or ‘I’) appears to be. Each ‘me’ exists only in the now, but is linked in more ways than one to future and past ‘mes’, just as the river exists today, and is different to the river yesterday, though they are connected by the flow of time.