I often use the made-up term "time-travel fallacy" to describe certain poor arguments. I'm wondering two main things:
- is this an already existing concept, and I just don't know the right name?
- is it ok to use this term in conversation as long as imply that I made it up?
- and maybe thirdly, is there anything wrong with this concept as I described it?
The way this kind of mistake arises is from the fact that it is extremely easy for people to imagine two distinct time-frames and argue from both time-frames at once, when they never could have been in a real position to do so.
In a real situation, they either would be in the past time-frame with no knowledge of the future, and no moral obligation to it either, or else they would be in the future time-frame, and the past time-frame would be in the past, and any knowledge gained from hind-sight would be irrelevant as far as decisions made in the past go.
Arguing as if both the earlier time-frame and later time-frame are both a part of the same present is the "time-travel" fallacy. The state of the later time-frame cannot be used to make decisions in the past. One way of describing this is with the phrase "hind-sight is 20-20", but I think that "time-travel fallacy" is a little more broad than that, since "hind-sight" is only one way of making this mistake.
A potentially controversial example that I am hesitant to use since I don't want to get side-tracked by the issue itself is abortion, but it's a good example. (It's not the only example, though.)
A common argument against abortion is to think about the future person that you would be aborting, or to point to existing people and ask whether you would have aborted them. This is the time-travel fallacy, conflating the future with the present, or the present with the past.
A person that exists presently exists presently, and you can't make decisions in the past based on the present. Similarly, a person that does not exist yet, but will in the future, still does not exist in the present, and you can't make decisions in the present based on the inferred state of the (distant) future.
(This is not meant to avoid consequences of actions; if A causes B, and B is bad, then you should avoid doing A, but if A and B are sufficiently removed from each other to the point that B can only be loosely imagined, and the future that B exists in is completely imaginary, then there is no such obligation. The point as far as the abortion thing goes is that you are not "murdering" the future person, because that person does not exist yet. You cannot argue as if the future is the present.)