[polishdude20]

Yes exactly. These scenarios assume some perfect world where, in the spur of the moment, you have guarantees of your actions. In the real world we can't guarantee a fat man will stop this train. In the real world, does you causing torture to save 5 people cause downstream future effects that actually make the world worse?

Say I tortured someone to save 5 people. Sure, 5 people would be saved and the argument this website makes says that where we stop. But what about the future consequences of you causing torture? The person you tortured comes back later and kills others because of the psychological harm you caused. Or the media makes you a hero and people start to think "Hmm torture, not that bad of a thing.".

If we are maximizing happiness for the largest group of people, we need to think about it over the largest span of time. And that's when things get really uncertain and murky.