I talked with a friend recently and he proposed the theory that there are an infinite number of time "periods" and that each one was in no way dependent on any other, meaning, even if I went back to February 8, 1998, 12 hours 16 seconds 89 miliseconds, and so on, and assasiinated a major political leader, that when I returned to my time period (However unlikely that may be) that leader would still be alive because his life on February 8, 1998 and son on, was not dependent on his life at the present. Opinions?