h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

If I could travel to any time, I would like to talk with myself in the past. Obviously, I would end up changing my own future, but since I would only mess up my future in a different universe, it wouldn't really matter. It's just that, there are a bunch of times in the past when I had questions I really wanted to have answered, and I'd like to go back and answer them.

Side note: If someone came up to me and said, "I'm a time traveler," I'd like to think that I would react reasonably. I would try to ascertain if they were in fact from the future, and then I'd discuss physics with them. I think that I would not freak out, as other people would. Anyway.

PhysicsMan

If you did travel back in time, and talk to yourself (ie at a time previously to now) wouldn't you already know you're going to do it, by having talked to your 'future' self?

Well, in a no-free-will, only-one-universe universe, yes. However, in a quantum multiverse, I could travel to the past of a different timeline, so that in the past of my own timeline, I was not visited.

PhysicsMan

So... you wouldn't actually be talking to 'yourself' as such? It would be more like an equivalent of you in a different part of the quantum multiverse?

Basically. With any luck, however, he would be similar enough to me at the given time that I would be unable to discern the difference.

PhysicsMan