do this he says that Immortal Truth is not just change, as the followers of Heraclitus said. It is not just changeless being, as the followers of Parmenides said. Both these Immortal Truths coexist as Ideas, which are changeless, and Appearance, which changes. This is why Plato finds it necessary to separate, for example, ``horseness'' from ``horse'' and say that horseness is real and fixed and true and unmoving, while the horse is a mere, unimportant, transitory phenomenon.