[Tadao]

Because in order for there to be a past to go to, the future must happen. Or I guess the now works, but still... even if you went back in time this second to do something in the past, your past would have known you did something unless you went up to yourself and told yourself that you did that. But you might not for some reason, so your past might not know what you did until the future.

I guess you could go find the past you and tell yourself about your antics, but you didn't obviously.