The standard trolley case is where a trolley is heading to a track with five people, and you can redirect it to a track with one person. It seems permissible to do so.
But now imagine that a trolley is heading to a track with five people, and you can redirect it to another track also with five people. Why would you bother? Well, suppose that you enjoy turning the steering wheel on the trolley, and you reason that there is no overall harm in your redirecting the trolley.
This seems callous.
Yet we are in cases like the five-five trolley all the time. By the butterfly effect, many minor actions of ours affect the timings of human mating (you have a short conversation with someone as they are leaving work; this affects traffic patterns, and changes the timing of sexual acts for a number of people in the traffic), which then changes which sperm reaches an ovum, and hence affects which human beings exist in the next generation, and the changes balloon, and pretty soon there are major differences as to who is in the path of a hurricane, and so on.
But of course there is still a difference between the five-five trolley and the butterfly effect cases. In the five-five trolley, you know some of the details of the effects of your action: you know that these five will die if you don’t redirect and those five if you do. But note that these details are not much. You still may not know any of the ten people from Adam. In the butterfly effect cases, you can say a fair amount about the sort of effects your minor action has, but not much more than that.
What’s going on? I am inclined to think that here we should invoke something about the symbolic meaning of one’s actions. In the case where one turns the steering wheel on the trolley for fun, while knowing epistemically close effects, one exhibits a callous disregard for the sanctity of human life. But when one has a conversation with someone after work, given the epistemic distance, one does not exhibit the same callous disregard.
It is not surprising if callousness and regard for sacredness should depend on fine details of epistemic and other distance. Think of the phenomenon of jokes that come “too soon” after a terrible event: they show a callous disregard for evil. But similar jokes about temporally, personally and/or epistemically distant events may be acceptable.