on being a crackpot

I love science (and science fiction). In SF authors frequently drift into time travel through worm holes or other means and thus create a paradox (two physicians walking down a corridor) that threatens the real world. And I read claims made in scientific magazines or books that mathematically it should be possible to go back in time just as we can go forward in time. But I'm a crackpot. So I don't think it should be possible to go back. And we go forward in time, not because time exists, but because we and the universe around us are constantly changing. We may not be aware of it, but the I who existed five minutes ago is not the I that exists as I type these words. I have changed. What we think of as time is only a measurement of the rate of change. Thus it is possible to use time as a hypothetical mathematical construct without it actually existing. Time is a function of the human brain. It measures change, which occurs in a wave across the universe. When we see the light of distant stars in the now, we are seeing it when those light waves reach us, but the star itself may be long gone in the real present. Or if it hasn't died, it has moved on to some other location from which its light may not yet have reached us. We are, then, I think, on the leading edge of a big bubble of change and that is why we cannot go back in time. Nothing exists in the center of the bubble.