Common sense is not a good guide to reality

Edouard Machery at IAI:

You’ve probably heard of the famous Trolley case. Here is one version: suppose a runaway trolley is about to hit five workers who, by accident, happen to be working on the track. The only way to prevent their death is by pushing a switch that will redirect the trolley onto another track. Unfortunately, there is another worker on this sidetrack who will be killed if the switch is pushed. The question: Is it permissible to push the switch, saving five people but killing one?

You probably know that this scenario, and many other similar ones, have been used to study moral judgment, or as many say, moral intuition both in neuroscience and psychology. You might even know that they have been used to study the design of automated vehicles. But what you perhaps do not know is that Trolley cases have been a mainstay of moral philosophy for decades. They are not only used to study how people think about the right and the wrong or about the permissible and the forbidden, but also about the right and the wrong or about the permissible and the forbidden themselves. The goal is to determine what is morally right and wrong, required, permissible, and forbidden based on these very cases.

Moral philosophy is not an outlier in philosophy in its use of thought experiments such as the Trolley cases. Metaphysicians use them and epistemologists are addicted to them in their effort to understand knowledge, justification, and other important epistemic notions.

More here.