Wouldn't it make logical sense that the present is unalterable by actions done in the past because if you're there to attempt going about doing it, it already failed?

For example, if I go back in time to assassinate Gandhi, I already failed because I didn't do it.

I suppose the essense of my point would be if time travel/alteration did exist, none of us would ever know about it because the change made would always be how it happened.

Seem like cyclical logic? It should.

The god reference fascinates me, because if you think about god enough to reference it, then no one has, or apparently ever will, go back in time to erase it. Why? Because that's not how it is now.