   Combined with the assumption that ‘Pegasus’ is not a name but a disguised definite description—that it is short for e.g., ‘the winged horse’—Russell’s theory of definite descriptions thus leads to a solution to the puzzle of true negative existential beliefs. The solution is to accept the second horn of the dilemma: the proposition is not about Pegasus. On this account, one can correctly believe that Pegasus does not exist, since what one believes is what is expressed by an utterance of (7), namely the true proposition that there does not exist a unique individual that is a winged horse. Clearly, Russell’s solution to the puzzle of true negative existential beliefs shows how, in Brentano’s own terms, “if someone thinks of something, the one who is thinking must certainly exist, but the object of his thinking need not exist at all” and furthermore the thought may be true. For further discussion, see the entry on  Bertrand Russell.