It’s Halloween, and philosophers everywhere are dressing up as obscure ideas and concepts that they’ll have to spend too much time explaining. Costumes are fun, but let’s not forget the horror, shall we?Philosophy has the power to strike fear into people’s hearts. Even the professionals. So let’s ask:

Which philosophical idea’s truth do you most fear?

(Yes, this question does not specify whether you’re supposed to take the probability of an idea’s truth into account when identifying it as the one you most fear. Such unsettling ambiguities you’ll just have to cope with this Halloween.)