Last spring, students from the Massachusetts Institute of Technology staged what was billed as the first convention for time travelers. Cleverly, they declared it would be the only time-travelers' convention ever needed, since anyone who missed the event could just travel backward in time to attend.
The chances of time travel are vanishingly small. First there is the problem that there would have to exist an infinite number of interwoven universes, each representing an instant in time, in order for there to be destinations to which time-travelers could journey. No one can prove there are not an infinity of universes each forever locked in an instant of time, but what are the odds? Second are the obvious causality paradoxes. If you went backward in time and prevented your parents from meeting, you would cease to exist; but if you ceased to exist, then you could not have traveled backward in time to prevent the meeting. Third is the already-altered problem -- if a future person went into the past and altered history, this would have already happened from our perspectives; history would already be altered and thus the current condition would be the normal condition, that is, not altered. The clincher is the free-will problem. If any future person with a time machine is debating whether to travel into the past, he or she would have no free choice in the matter, because from the standpoint of the past the journey has already either occurred or not occurred. For the theological flip side of this argument -- God cannot know the future because if the future is already determined then God has no free will -- see my favorite philosopher, Charles Hartshorne.
Wednesday, November 16, 2005
Since Mr. Pterodactyl apparently missed it, here's a tidbit from Tuesday Morning Quarterback: