With Plato the interest in ideas is very different. He is a mathematician. He is fascinated with ideas of number and of geometrical form. Mathematics to many minds seems to consist of a world of pure reason which is more permanent than the world of things. Philosophers before Plato had wrestled with the problem of change. Existence was seen to be a stream in which everything is carried along toward its inevitable destruction. Every object at any moment is but the cross-section of the process of its becoming something different. Our bodies grow and perish, so also does all pass away. The rivers run to the sea, the plants die, the temples of the gods crumble. Even the mountains are but waves on the surface of a sea of time into which all things sink and are lost forever. How can the temporary objects which whirl past in the course of their transformation be said really to exist? Existence surely must be endurance. I think that Plato, like many thinkers since, saw the terrifying significance of the flow of things and sought security and “reality” in something permanent outside the process of change. What was more natural than that he should turn to the realm of abstract thought? The objects we perceive change, but a concept always means the same. The world may pass away, things may each turn into other things, as water into vapor and fire to smoke and the body to dust, but two and two are still four, and the sum of the angles of a triangle remains constant. Hence above and behind the world of objects there is a world of ideas into which the teeth of time cannot gnaw. You have only to believe that ideas have an existence independent of the minds which think them and all is transformed. Instantly you step out of Time into Eternity; form without content; number without things to be counted; common properties of objects stripped of the objects in which such properties inhere; the forms of logical discourse, minus the things talked about and the talkers as well; goodness, without anything in particular to be good; beauty in general, independent of any concrete beautiful thing, truth universal and absolute and outside experience. All this is now the _real_ world, and the world of troublesome, fleeting objects becomes a shadow and a delusion. Knowledge is knowledge of the “real.” In other words, knowledge is about itself. The more abstract and universal an idea is the more reality it has. The mind persuades itself that it possesses Being, Motion, the Good and the Beautiful merely by the magic of thinking about them in abstract terms. The universe is transformed into an ordered system of postulates and verbal exercises. Education now is something more than the clarification of concepts; it is initiation into the superworld of eternal verities.