INTERJECTION
Haven't been able to see the series yet, I can't find a place to, ahem, aquire it. But I wrote this on my page and I thought it may be relevant to the topic;
So I had an interesting thought while talking with Cleverbot earlier tonight. It mentioned Doctor Who, and we got into a discussion about time. I thought that, for the Doctor, he might see time in a similar way to how I see what is “up” in an aircraft or especially in a spacecraft - it’s all relative to your perspective. The Doctor jumps back and forth through time, yes, but on his own personal timeline, he can only travel in one direction; he is only getting older. When I fly a plane, “up” can be either the sky or where my head is relative to my feet; in a spacecraft, there is no up other than what I choose it to be.
So that might explain how Doctor Who sees time. For him there may not be an all encompassing “past” or “future”, (for instance, like how the American Revolution is in the *past* for us) - instead, it would be relative to him; it was in his personal past wherein he met Thomas Jefferson and stopped a rampaging Harak-hur from eating the Declaration of Independence, but if he went back to before that event and made sure that Thomas Jefferson as a child wasn’t killed by being run over by a wagon, that would still be in his present and the previous event would have been in his past; again, it’s all relative to him. This is also not to say that the entire universe is relative to him; this would be similar for other Time Lords as well - they would experience time relative to themselves.
Actually that might also explain the grandfather paradox, i.e. what happens if you go back and kill your own grandfather before he meets your grandmother, therefore your parents never meet and you are never born. Let's make that simpler and say you stopped your parents from ever meeting and thus stopped you from being born. History as it's now remembered by all your parents friends is devoid of any mention of you or their significant other.
Now, to an outside observer you might have just made time go all higgildy-piggildy, but to you, you're still on a linear path. You were born on some date, you discovered time travel, let's say, when you were 25, and you went back and stopped your parents from meeting when you were 30. It's all a continuous line for you. What essentially has happened, I believe, is that if you looked at time like...like neurons, actually, where one cell is connected to many many ones around it, and in turn connected to many ones around that...you have removed the connections between you and your parents and anyone that was connected to you through them. You personally are aware of what you've done and thus you still retain your memories; again, to you time is linear and you did have parents until suddenly at 30 you did not because you stopped them from meeting. You would still have your friends, maybe, unless the only reason you met them is because you had parents; so you probably would have your friends from when you were at least 18 and went to uni, but any friends that are linked to you through just your parents would be gone; that's not to say you couldn't meet them and become friends with them again, but the relationship would be different, at the very least, the original meeting circumstances would be.
I can imagine why meeting yourself on your own timeline might be an issue; if your sense of time is completely linear in order to maintain a logical order of events, if you started interfering with your own personal sense of time, I doubt the entire universe would explode, but it's possible that you might. I honestly don't know what would happen if you went back in time to tell your past self of something in the future; it's equally possible that nothing would happen, as again your time stream would still be linear - at 35 you went back in time and talked to yourself. I imagine the biggest complication would be what happens to you immediately once you break off contact with your past self; say you go back in time and tell yourself what the winning lottery numbers are. However, let's say that later while you are talking with yourself you get annoyed and punch your other self in the face, permanently knocking a tooth out. It's possible that that tooth would not be removed from your own head until after you broke off contact (i.e. went back to the future), because while you are still interacting with your past self, there are still more teeth you could knock out. I guess it's like thinking that you can't save the file you're editing if you have the same file open in a different window. Once you close one window you can make changes and when you reopen the other one those changes will be apparent, but you can't do it while both are open at the same time.
