The
analogy of the sun (or
simile of the sun or
metaphor of the sun) is found in
The Republic VI (507b–509c), written by the
Greek philosopher
Plato as a dialogue between
Glaucon (Plato's elder brother) and
Socrates (narrated by the latter). Upon being urged by Glaucon to define goodness, a cautious Socrates professes himself incapable of doing so. Instead he draws an analogy and offers to talk about "the child of goodness" . Socrates reveals this "child of goodness" to be the sun, proposing that just as the sun illuminates, bestowing the ability to see and be seen by the eye, with its light so the
idea of goodness illumines the intelligible with truth. While the analogy sets forth both
epistemological and
ontological theories, it is debated whether these are most authentic to the teaching of Socrates or its later interpretations by Plato. The sun is a metaphor for the nature of reality and knowledge concerning it.