If time travel were possible would it wrong to kill people in the future?

If we traveled in time would it be OK to kill people from the future? After all they haven’t been born yet and once we observe them we could “kill” off a bunch of them by making perfectly legal choices such as choosing not to have children. And I am not sure what would happen once we went back to our original time, would this person even still “exist”? So what do think of going forward to kill people? Personally, I think it would be wrong because at the time you kill the people you are in their time and thus they do “exist”. However, I can’t see anything wrong with sending a bomb into the future to kill people and then sending yourself into the future a safe distance away to observe the death. Please ignore any time war consequences.
Obliviously, going back in time and killing people or interfering in anyway would be too dangerous.

This was inspired by the South Park on tonight.

In my view, you wouldn’t really be killing them. You’d just be preventing one possible future from being the future that you experience.

Dude, if you’re gonna get in a Time War, you want to attack the Past, not the Future.
Would you rather fight guys with lasers and jetpacks and killer robots or guys with sticks and spears who wipe their asses with corncobs?

But seriously, I’d have to argue that killing is always wrong, except in self-defense. Regardless of when or where, those people still die.

The fact that they’re there means that your decision to not have children didn’t work, for some reason or another. So I’m not sure that argument flies.

I’m not positive I understand the question.

If you go forward 50 years and kill someone then 30, how could that effect the person until he is 30? Isn’t he still going to be born and live in just the same way for the those 30 years, whether you time traveled or not?

In any case, killing a human generally requires some imperative – self defense or some overriding social motive such as war or knowing with some certainty allowing the person to live would led to substantially greater evil.

If, by killing someone from you future you mean acting in such a way in the present as to exclude the possibility of their ever existing, I don’t know that that would be a crime. I don’t even know if that would be immoral.


I get a time machine. I go ahead 20 years and find out I have a son who drives me nuts and is generally being a big pain in the ass. “No problem” I say to myself. “I’ve got your number!” Then I got back to the present and get a vasectomy, thus ensuring his never being born. Is that illegal? Immoral? Why? How?

What a weird prospect. Maybe I’ll get back to you after I think about it for a while.

Wouldn’t it just be easier to stop the future from happening by having all the men get in a big pile and have sex with each other?

“That’s it boys! Back in the pile!”

The question is really about travelling back in time. After all, if I were to wait 50 years and murder someone, I’ve travelled forward in time (at the usual rate) and killed them, exactly as you propose. It’s only interesting if I then travel back in time and prevent the victim from being born. Have I then “undone” my murder?

I say no. If their is only one timeline, and past and future are both determined, then you cannot change anything. Whatever you attempt to do when you go back, the person will still be born and will be murdered by you.

If their are multiple timelines (the many worlds version of time-travel) then what occurs in one world is as morally relevant as what occurs in another. (Of course you may argue that if every possible world exists, then nothing is morally relevant. In this case, you still haven’t undone your murder, you’ve just said that all murder is acceptable.)

Finally, if their is only one timeline, but only the past is determinate, while the future is mere potential, then you can, in fact, prevent someone from being born. But this theory would be disproven by the act of traveling back in time–what is potential to those in the past is actual to you; you can’t experience something which is not actual. If you experienced that future, then it clearly exits, if not as the future of the world you’re in now, then as the future of another world. You can’t “undo” anything.

Only to find out that the MWT was wrong when you get back to that time frame, and your SO was cheating on you, and you’ve just killed someone who was never your son to begin with.

You guys must really be bored…

We may be making the mistake here of assuming that there is a definitive answer to a problem that is rooted in a number of impossible hypotheticals.

Firstly, the whole if thing - if time travel was possible. Yeah, but what if it isn’t? if pigs could fly, would bacon taste like duck? We waste our time trying to think of a sensible, logical argument to a question that isn’t grounded in normal sense and logic.

Secondly, the question is really if I could perform an action, then cleanly undo the action, does the action matter? The answer to this one depends on your point of view; from the POV of the actor, yes, it matters as much as if you couldn’t undo it - you’ve performed the action and this is morally wrong, or it isn’t. From the POV of the subject, the ‘clean undo’ means it never happened, so there’s no question to answer.

Oops, pardon me. After a large meal last night, I’m afraid I just “moved the butterfly’s wings”.

Imagine my embarrassment if it kills 10,000 people in a July hurricane.

I DO own a time machine. Fortunately for our timeline it works only for moving forward in time, and usually takes me forward only about 8 hours. I certainly don’t see how killing someone tomorrow will be less a crime than Killing someone today.

If you ask me, you are always in the present. Time travel has nothing to do with morality, IMO.