Assume for a moment that time travel into the future was possible. Would this be evidence that our existence is deterministic?
Agreed. But traveling back words? My answer to the OP would be...maybe. That is a tough one. I'm going to think about this one.
A few years ago MIT had a meeting for time travelers. Inviting time travelers from the future to the meeting. No one showed up.
There is a new theory-that time is actually not a 'dimension'. It is a construct that our brains 'invented' to help us explain and deal with our reality.
What if people can't come back in time yet because time-travel wasn't invented yet, and time is linear right now? So then, when time travel is invented, they will be able to come back to the past. So then, effectively, there will be two time-spaces, the one pre-time travel, that ended when time travel began; and the second one post-time travel. But we live in the first?
So we are the first. Still let's say in 20 years we perfect time travel-we could still travel back in time to any time. Time travel basically removes time. All things are happening at the same time. Right now- I am typing this on my computer. U2 is playing a few miles away. There are hundreds of cars travelling on I-95. These are all happening in my 'time'. If I could time travel-everything is happening 'at the same time'. I am just going there. Just like I could be here right now typing or I could be at the U2 concert. But if I could time travel I could travel to any time (could I travel to any space? of just stay in my one place thru time?) so basically everything in history is happening all the time-so I could go anywhere-including travelling back to the MIT party.