Temporal anomalies

Lots of folks like time-travel stories. They like time-travel paradoxes. Even if the scenario is implausible, they suspend disbelief if the story is enjoyable.

The classic time-travel paradox is the grandfather paradox. That's a genuine antinomy. An impossible state of affairs. Internally contradictory.

If a man travels back into the past and kills his granddad (before he begets his dad), then the future he came from never existed. He never existed in that future in the first place. The scenario negates a necessary precondition for him to exist at all. 

At least if there's only one past or future. If, on the other hand, you have an Everett universe, then these may represent forking paths. But I don't wish to pursue that line of thought. It's just a backdrop to discuss something else. 

In The Voyage Home, there's this exchange between Spock and  Kirk:

Spock: [in response to Kirk pawning his antique spectacles from The Wrath of Khan] Excuse me, Admiral. But weren't those a birthday gift from Dr. McCoy? 

Kirk: And they will be again, that's the beauty of it.

This, too, is paradox, but a different kind of paradox. A bootstrap paradox. Unlike the grandfather paradox, this temporal anomaly isn't internally contradictory. It doesn't negate a necessary condition for the scenario to be possible. 

Rather, it poses a different dilemma: a causal loop. A circular chain of cause and effect. The problem is, how does that get ever started?

Kirk having the glasses to sell in the past is the result of Bones giving him the glasses in the future, while Bones giving him the glasses in the future is the result of Kirk selling them in the past. It's a mutually dependent relation, where each is caused by the other and each causes the other. But that can't be. 

Yet unlike the grandfather paradox, this temporal anomaly doesn't seem to be contradictory. What is required is for something outside the causal loop to originate the causal loop as a whole. To originate the relation en bloc. 

That can't happen from within the causal loop itself. But can something independent of the loop, external to the loop, make that happen? 

Suppose the B-theory of time is true. Suppose God actualizes the entire timeline–past, present, and future–at once. In that case, history is a given totality–although we don't experience it all at once. We only experience the part of time we occupy.

On that model, it seems possible for the timeline to include causal loops. They can't be phased in incrementally, but if both the past and future ends of the relation, as well as intervening events, are instantiated at one stroke, then it seems to be metaphysically possible.

Mind you, if the Star Trek scenario wasn't fictional, if we could take it seriously, it would be unnerving. For it would mean they always do that. 

There's a sense in which a self-fulfilling prophecy is a causal loop. Where information about the future affects the past–and vice versa. Both rely on an agent that's outside the framework. Same thing with the predestination paradox. 

As a matter of fact, prophecy does affect the past. It has an influence on the choices and actions of people in the past who believe it. And that, in turn, impacts the future. Their choices and actions in response to prophecy contribute to the conditions of its eventuation.

If the world was a closed system, that wouldn't be possible, because knowledge of the future would have no independent source. Within the system, that can't happen. But since Biblical prophecy involves an open system, where God reveals the future to the prophet or seer, that's the point of origin.  Incidentally, this could be the case given either the A theory or the B theory of time. 

Why do I bring this up? Lots of people who like science fiction wish some temporal anomalies were feasible. That would be fun. And if a physicist proposed a realistic mechanism, they'd be more than happy to accept it.

When, however, it comes to divine prophecy, many will reject that out of hand, due to their antipathy towards God. Likewise, they ridicule mature creation, even though the metaphysics behind a temporal paradox are at least as exotic as mature creation.