One of the central themes of the present book, and one that will continue to recur, is the importance, for the way in which he writes, of Plato's awareness of the difference between his view of things – what, through Socrates, he calls the philosophical, or the true view – and the way things appear to ordinary non-philosophical folk, whether these are Socrates' interlocutors, or Athenians/Greeks in general; or, by implication, the generality of the readers of the dialogues. Plato's sense of his, and his Socrates', ‘out-of-placeness’ (their atopia), in relation to run-of-the-mill perspectives, and of the barrier to comprehension that this threatens to raise, is one of the chief determining factors shaping the dialogues. And – as I shall go on to argue in the following chapters – nowhere is this clearer than in the Republic. In this Introduction, I propose to try to demonstrate the point in relation to a particular context in the dialogue: the simile of the cave. The outcomes of the discussion of this one context will turn out to be unexpectedly wide reaching.

In the simile of the cave, the form of the good is still at the centre of the image that is presented to us, as it has been in the two similes that precede it (the sun and the divided line).