Plato and Common Morality

Abstract

In the Republic, Socrates undertakes to defend justice as being in itself a benefit to its possessor. Does he do this, or does he change the subject? In a well-known article, David Sachs pointed out that there seems to be a shift in what Plato is defending. The challenge to Socrates is put by Thrasymachus, who admires the successful unjust man, and by Glaucon and Adeimantus, who do not, but are worried that justice has no adequate defence against Thrasymachus. In all these passages justice is discussed in terms of the non-performance of actions which are regarded as unjust according to common morality; Sachs calls this common concept of ordinary justice ‘vulgar justice’.