You have to use ex ante probabilities—just because the fat dude stops the trolley once in a million times doesn’t make it a moral act that one time. In practice we almost never know the probabilities, which leads to the ends-means conclusion. What’s interesting is how many folks are willing to, in the face of not knowing the probabilities, substitute intentions. Which has its own saying.
Doug S,
You have to use ex ante probabilities—just because the fat dude stops the trolley once in a million times doesn’t make it a moral act that one time. In practice we almost never know the probabilities, which leads to the ends-means conclusion. What’s interesting is how many folks are willing to, in the face of not knowing the probabilities, substitute intentions. Which has its own saying.