A group of philosophers tried to throw out every unanswerable question at once
In 1920s Vienna, a circle of philosophers and scientists proposed that a statement is only meaningful if it can, at least in principle, be verified by observation or experience. On that standard, most of traditional metaphysics, ethics and theology wasn't false so much as meaningless, literally nonsense dressed as deep questions. The movement eventually collapsed under its own rule: the verification principle itself turned out to be unverifiable.