  [E]ven if it is one thing for ‘this tree is an oak’ to be true, another thing for ‘burning live cats is cruel’ to be true, and yet another for ‘Buster Keaton is funnier than Charlie Chaplin’ to be true, this should not lead us to suppose that ‘true’ is ambiguous; for we get a better explanation of the differences by alluding to the differences between trees, cruelty, and humor. (Sainsbury 1996: 900; see also Quine 1960: 131)