future already from when you said that the future doesn't exist. I might have the means to travel back in time now & come & turkey slap you...Sorry I wouldn't really do that...but get my point??? :o) Post Edit: Jkool has a great answer ..in fact I have a book that deals with that very topic. Time travel IS possible and we all do it. You could say that reality is an illusion that exists only in our mind ..( the old If a tree falls in a forest & nobody is there to hear it fall..did it really fall ..routine) From the point of view that all reality is within our brain...then surely we can and do travel back in time when we use our memory. There are also weird Quantum Physics involved that say this is possible. Quantum Entanglement and De-coherence come into it somewhere and the flux of 'particles' popping into and out of existence. But this is at the sub-atomic level. How that translates into our macro level of existence is that your guess is as good as any body else's. Post Post Edit: The movie.."The Butterfly Effect" gives a wonderful example of what could happen if we were able to go back in time and change things. It's not what you would expect. Psychologically speaking...we all fantasise about time travel as it gives us the opportunity to do the WHAT IF scenario. What if I had only done this or that..my life would be better.