Ahh...this is a classic scenario that is brought up when there is a question about the moral aspect of how people value life. I think it's often combined with another question where both groups are going to die but you don't have to push anybody down and you have to choose a lever where it will send it to either the group with the largest or smallest number of people. I think the first time I read about this question a long time ago (or something very close to this question) I thought long and hard about it and came to the conclusion that I wouldn't kill one person in this question just to save the others as I figured it was wrong. I'm also assuming that the question doesn't have some ambiguity in it where the people in the trolley might die anyhow, where your defending yourself against future death and somehow the world's at state, or anything like that and it's just to determine who's life you would allow to live. The flaw in the question, if you could call it that, is the fact the deaths of them are different while some people that ask the question don't realize it. Some would tell you that you are in effect killing people either way and that's not the case. I think the difference in letting the people on the trolley die is that it's in effect fate or some quirk of reality that is killing them and not yourself. It's effectively reality's fault if they die and not your own. Your choosing to let people die is the choice that has been forced upon you. If you push somebody over to save the rest of the people however then in effect you are directly responsible for that person's death in a way your weren't with the others. I think that is the difference between the two and if that difference isn‘t understood then it‘s not really a fair question.