Phaedrus

When the souls we call "immortal" reach the rim, they make their way to the outside and stand on the outer edge of heaven, and as they stand there the revolution carries them around, while they gaze outward from the heaven. The region beyond heaven has never yet been adequately described in any of our earthly poets' compositions, nor will it ever be. But since one has to make a courageous attempt to speak the truth, especially when it is the truth that one is speaking about, here is a description. This region is filled with true being. True being as no colour or form; it is intangible, and visible only to intelligence, the soul's guide. True being is the province of everything that counts as true knowledge. So since the mind of god is nourished by intelligence and pure knowledge (as is the mind of every soul which is concerned to receive its proper food), it is pleased to be at last in a position to see true being, and in gazing on the truth it is fed and feels comfortable, until the revolution carries it around to the same place again. In the course of its circuit it observes justice as it really is, self-control, knowledge -- not the kind of knowledge that is involved with change and differs according to which of the various existing things (to use the term "existence" in its everyday sense) it makes its object, but the kind of knowledge whose object is things as they really are. And once it has feasts its gaze in the same way on everything else that really is, it sinks back into the inside of heaven and returns home.