In the classic film Lawrence of Arabia When Lawrence returns with the man lost upon God’s Anvil and presumed beyond hope of saving he tells Ali that ‘Nothing is written.’ His meaning is that nothing is predetermined by Allah or God but that our fates are our own. The question about what is or is not predetermined is not one that is restricted to matters of gods and theology but is strikingly relevant to science-fiction. No where is this more on point than in the sub-genre of science-fiction, time travel.

A common conceit in time travel stories is that the past is fixed but that the future is open to change, however that view is one that upon closer inspection, at least to me, falls apart

Let’s consider a person we shall we refer to Character Delta-0, he or she is a person living in their ‘present. Delta-0 can look back at their past and perceive their earlier selves but under the ‘past if fixed’ perspective nothing about that history can be changed. Every earlier version, lets call them Character Delta-minus, is stuck on a fixed path that leads to Delta-0. Looking forward in time Delta-0 can see innumerable possible paths, each containing different versions of their future selves that we’ll call Delta-Plus. Which Delta-Plus Delta-0 become depends on Delta-0’s choices, there is no fixed path.

So far this is a very classic time travel interpretation, but it is fixed upon a single point of reference.

The truth of the matter is that all of them are Delta-0, Delta-minus, and Delta-plus from each other’s viewpoints. If we step back and center on Delta-Minus, the two other Delta are both Delta-pluses to this character and there are an endless number of paths forward through time and one some lead to those particular Delta-Pluses. If we center our focus on Delta-Plus, both of the other characters are Delta-Minuses and there is an immutable path leading through their histories to that particular Delta-Plus who of course sees himself as a Delta-0.

This the essential contradiction in moving forward and backward in time. The future is merely someone else’s past and the past cannot be fixed without also fixing the future because of its nature are an even more distant future’s past.

If we simply unfix everything, then the past becomes a fog of possibilities and any particular past hold no essential prominence as true ‘history.’ The history I know is just that what I know and no more valued than any other. There can be no time police ensuring a stable past without that same unit enforcing an unchanging future.