Platonist theories postulate number as a fundamental category itself. The first postulate of special relativity declares the equivalency of all inertial frames. Such a hypothesis was termed a "postulate". Therefore, we can postulate the existence of immortality. He spoke literally of "the postulate of relativity". Nasir al-Din attempted to derive a proof by contradiction of the parallel postulate. This conclusion by Bunnett is a contradiction from the Hammond postulate. "Non-Euclidean geometry" refers usually to geometrical spaces where the parallel postulate is false. This postulate is a physical postulate of existence. Non-Euclidean geometry considers spaces where Euclid's parallel postulate fails. It exists today as the basic postulate of classical homeopathy. But since there are no explicit representation, one can only postulate a possibility. But since there is no explicit representation, one can only postulate a possibility. Posidonius was one of the first to attempt to prove Euclid's fifth postulate of geometry. This fact is equivalent to Euclid's parallel postulate.