Moral dumbfounding is a term used in philosophy and psychology to refer to cases in which people hold moral intuitions that go against reason, or at least, that they do not or cannot support with rational arguments.
There are quite literally thousands of examples, some of which may work to 'dumbfound' you, and others that will not faze you at all. However, it is important to note that the dumbfounding occurs not when a person says "oh no! I am confused!", but when they are unwilling or unable to respond to a reasonable and relevant question.
Potentially dumbfounding situations include:
- If you hold that saving lives is inherently good, you should agree that switching a trolley from a track on which it will run over and kill five people to a track on which it will kill one is a morally good act.
- If you hold that saving lives is inherently good, you should agree that pushing a hefty person off a bridge to impact and derail a runaway trolley about to kill five people is a morally good act.
- If you believe that God is good, you should therefore accept that killing innocent babies is often a good act, and not protest things that cause babies to die.
- If you believe that saving lives is good, then you should give all of your money to causes that save lives, sparing only enough to keep yourself alive and employed. Also, you should donate a kidney, already.
- If you believe that incest is bad because it has negative effects on the genetics of resulting offspring, then you should be okay with cases of incest in which effective birth control is used.
- If you believe that global warming is a serious threat to humanity, you should believe that having children is, at best, a highly dubious moral act.
- The family dog runs into the street and is killed by a passing car; what moral rule do you refer to in order to justify not eating the delicious, delicious dog meat -- or at least feeding it to those hungry dogs at the dog pound?
The fact that moral dumbfounding is common has been used to argue that most people's morality is built on spurious moral intuitions caused by their subjective enculturation; this in turn has been used to argue by some that moral intuitions are weak and useless, and by others that they are one aspect of society that cannot be improved by rational thought, as they are functional and optimized for the norm, and not optimized for every conceivable edge case. It should be emphasized that just because someone cannot express a reason why a moral loophole is bad does not mean that it is not bad; it is often hard to express things that you have not expressed before, and, of course and always, the fact that one person cannot provide an argument for something does not mean that a good, sound argument does not exist.