In the Republic , Socrates presents men as prisoners in a dark cave, bound and forced to look at a wall against which are projected images that they take to be the beings and that are for them the only reality. Freedom for man means escaping the bonds, civil society's conventions, leaving the cave and going up to where the sun illuminates the beings and seeing them as they really are. Contemplating them is at once freedom, truth, and the greatest pleasure. Socrates's presentation is meant to show that we begin from deceptions, or myths, but that it is possible to aspire to a nonconventional world, to nature, by the use of reason. The false opinions can be corrected, and their inner contradictions impel thoughtful men to seek the truth.
Education is the movement from darkness to light.
Reason projected on to the beings about which at first we only darkly opine produced enlightenment. The moderns accepted that reason can comprehend the beings, that there is a light to which science aspires. The entire difference between ancients and modern concerns the cave, or nonmetaphorically, the relation between knowledge and civil society. Socrates never suggests that, even in the unlikely event that philosophers should be kings and possess absolute wisdom, the nature of the cave could be altered or that a civil society, a people, a demos , could do without false opinions. The philosophers who returned to the cave would recognize that what others take to be reality is only image, but they could not make any but the happy few able to see the beings as they really are.