There is some truth to this, but if you haven't yet surveyed the extensive literature on the subject, then perhaps the review articles that I posted at the top will go some way towards disabusing you of the notion that this is a settled issue in philosophy. — SophistiCat
I take it that nothing is ever settled in Philosophy. But I've also noted that if you swim against the tide, the onus then is usually on you to make a very strong case, and if you swim with the tide, you need say little to defend your position.
Does this make the tide necessarily right? Of course not. Tides change from time to time, and philosophical debates can rage for thousands of years. But if we are to believe that Philosophy is of any use at all, other than just as a means of honing one's ability to think and argue well and coherently, it seems that one must be committed to the belief that following the tide is the path that is generally most likely to lead to knowledge.
I did some skimming of the references you provided that were actually available to me. One thing I noted that was of interest is that in a closed timelike curve, there can be no consistent entropy gradient that gives time its forward arrow. If there were such a gradient, you couldn't return in the loop to the same point in space-time, since that point must have the same entropy, and consequently it wouldn't be a closed curve. It seems that this would make traveling around one unpleasant. But, I suppose if it were large enough, you could refrain from going all the way around the loop, and I suppose there could be a gradient that does not change direction in the part that you stay on. Well, this is probably neither here nor there for this discussion, but I found it an interesting worry.
So, I've been thinking about time-traveling wormholes instead. Let's say that you enter a wormhole headed for the past. Your lovely wife died and you are heartbroken. You wish to be with her again. While you were with her, she mentioned that she had had a wonderful boyfriend in the past who was a lot like you, only older. Unfortunately, he eventually died in a freak gardening accident, but they had been very happy together for many years while he was alive.
You decide that you must have been/will be this man, and so you enter the wormhole and begin your new life as your dead wife's sugar daddy. Only she's no longer dead from your new location in time.
So what is happening here with respect to existence? We already know the eternalist view, so I will elide that. But there are two other possibilities that I can think of:
(1) When you enter the wormhole, reality splits in two, and now there are two presentist universes. Though they are both on deterministic rails. Such a split happens every time someone enters the wormhole. Oh, but wait? What about random particles that enter the wormhole. Do they cause a myriad of forking realities?
I find this view to be highly unsatisfying.
(2) Presentism is correct and the only existing point in time is now. When you enter the wormhole you cease to exist. I.e., you die. You committed suicide. It's really very tragic.
But to soften this tragedy, there was a time in the past when there were two of you. Unfortunately, one of you just appeared without any cause or history, and so this mysteriously appearing version of you is not really you at all, but rather a weird clone of you made by space and time out of nothing but random particles and energy.
When you entered the wormhole, you were hoping for a continuity of consciousness. You expected to be traveling into the past. But nothing could be farther from the truth. You died. Nothing more. And it just so happens that someone else just like you, but not you, was brought into existence, at precisely the time and place you wished to travel to. Not only is your suicide a tragedy, but it is compounded by the fact that in the distant past some imposter got to spent all this wonderful time with the woman of your dreams.
I also find this view to be highly unsatisfying.
|>ouglas