Philippa Foot is most known for her invention of the Trolley Problem thought experiment in the 1960s. A lesser known variation of hers is as follows:
Suppose that a judge is faced with rioters demanding that a culprit be found for a certain crime. The rioters are threatening to take bloody revenge on a particular section of the community. The real culprit being unknown, the judge sees himself as able to prevent the bloodshed from the riots only by framing some innocent person and having them executed.
These are the only two options: execute an innocent person for a crime they did not commit, or let people riot in the streets knowing that people will die. If you were the judge, what would you do?
The entire point of these problems is that they serve as an intuition pump for what people are morally prepared to do.
If the scenario doesn’t make sense, people will respond to it in unpredictable ways.
In the real world, if I push a fat man in front of a train it won’t slow the train down and save the lives of five people people further down on the tracks, it’ll just kill six people and I’ll be a murderer.
So when we find that people are more uncomfortable with pushing someone under a train vs throwing a switch to make the train hit them, does that mean that they instinctively don’t trust the premise and think maybe that they’ve killed someone for no reason, or that they prefer the extra layer of indirection. We don’t know, and this really reduces the value of the thought experiments.