But progress in knowledge has made us aware of the superficiality of Plato's lumping of individuals and their original powers into a few sharply marked-off classes; it has taught us that original capacities are indefinitely numerous and variable. It is but the other side of this fact to say that in the degree in which society has become democratic, social organization means utilization of the specific and variable qualities of individuals, not stratification by classes.
Plato defined a slave as one who accepts from another the purposes which control his conduct. This condition obtains even where there is no slavery in the legal sense. It is found wherever men are engaged in activity which is socially serviceable, but whose service they do not understand and have no personal interest in.
The breakdown of Plato's philosophy is made apparent in the fact that he could not trust to gradual improvements in education to bring about a better society which should then improve education, and so on indefinitely. Correct education could not come into existence until an ideal state existed, and after that education would be devoted simply to its conservation. For the existence of this state he was obliged to trust to some happy accident by which philosophic wisdom should happen to coincide with possession of ruling power in the state.
While [Plato] affirmed with emphasis that the place of the individual in society should not be determined by birth or wealth or any conventional status, but by his own nature as discovered in the process of education, he had no perception of the uniqueness of individuals. For him they fall by nature into classes, and into a very small number of classes at that.