A few more thoughts.
But if he knew he traveled back in time, he could conceivably decide not to. Or does fate somehow push him in the right direction? That would be magical.
Swartz’s view on this is that it’s you who is assigning him magical powers in the first place. I think he’s got this bit right, at least.
If he knew he was going to travel back in time his future would be that he traveled back in time.
So in order to decide not to travel back in time under these circumstances he would need to have the power to change his future from what it will be.
But he can’t do that because it’s logically impossible.
We can’t change the present from what it is.
We can’t change the past from what it was.
And we can’t change the future from what it will be.
Time travel into the past involves no intrinsic contradiction. The appearance of contradiction arises only if one illicitly hypothesizes that the time traveler can change the past from what it was. But that sort of contradiction has nothing whatever to do with time travel per se. One would encounter the same sort of contradiction if one were to hypothesize that someone now were to change the present from the way it is or someone in the future were to change the future from the way it will be. All these latter notions are logically impossible. But none of them is intrinsic to the concept of time travel.
One should take care in describing time travelers not to give them logically impossible capabilities, e.g. the capacity to change the past from the way it was, the present from the way it is, or the future from the way it will be. But once one has done that, then there is no need to think the concept of time travel to be logically impossible.
(bold emphasise by me)
So all this I think is right, then he goes further.
It just turns out to be a contingent fact about this actual world that accelerated backward travel in time does not occur.
Here he takes the view that we know it will not happen because if so we would have met time travelers from the future. Seems we can’t be sure enough to know but I wouldn’t want to quibble over that.
The important point is he believes it’s a contingent fact that it doesn’t happen and knowing his philosophy, I know what he means is even if it were to be a contradiction of a physical law that would not restrict us from being able to do it because physical laws are contingent facts.
Here, it seems to me, he goes completely off the deep end.