This is a slightly surreal one (inspired by a daydream).
You are visited by a vision of the future (or time traveller, or whatever). You see that in the future that ebola is going to become airbourne and extremely virulant, then spread around the world via birds (the science isn’t incredibly important). Most of the human race will be wiped out, say c.5,000,000,000 people dead.
You can stop this however, by perpetrating one massacre of 1,000 people, thereby stopping the mutation from occuring. (Somehow you have the means to carry-out this atrocity). There is no time or it is not possible to stop it otherwise (no-one will believe you etc). ie. your only option is to kill the future carriers.
Now, there are three different scenarios
1. This is going to happen in about a weeks time. Most people would say that they would kill the thousand to save the 5 billion. True liberals won’t, (and Catholics), but everyone else probably will.
2. This is going to happen in a year’s time. Again, I think that most people would choose the greater good.
3. This is going to happen in 200 years time. You have to kill the first carriers’ ancestors. This is the one that I wonder about. On the one hand, future people are still people. On the other, is it really right to kill people now, to save those who won’t be born for generations? At what point can you put up your hands and say “I can’t take this into account any more”, thats too far into the future?
In short, what do we owe to our descendants, and should a future life be weighed the same as someone in the here and now?