An argument is a set of premises leading to a conclusion. The strength of this “leading” can vary. Sometimes, that all the premises should be true but the conclusion false is logically absurd, and sometimes it’s only unlikely. We’ve all encountered arguments such that its premises are lovely, the connection between its premises and conclusion is very strong, and its conclusion is incompatible with other propositions we believe. When this happens, we’re forced to give up either some of the premises or these other beliefs. We should give up whatever we are less sure of. In my experience, arguments with the most unpleasant conclusions have premises such that one is far less sure of them than he is of the beliefs he would have to give up to accept the conclusion.