Introduction Plato Theory of Justice
The sub-title of the "Republic" shows the extra-ordinary importance; which Plato attached to justice. Plato wanted to bring to an end the prevailing degenerate conditions and political selfishness rampant in Athens, in order to save his beloved Athens from decay and ruin. He saw in justice the only panacea of saying Athens from degradation and decay and propounded his theory of justice.
Plato Definition of Justice
The fundamental issue raised by Plato in his book "The Republic" is the definition of justice. To understand the Plato Theory of Justice is essential to mention definitions of justice given by some early Sophists, which Plato narrated in his Republic.
The Theory of Cephalous (Traditionalism)
Polemarchus supports this Cephalous definition of justice by saying that justice means helping one's friends and harming one's enemies. Plato rejects their definitions. Similarly it is difficult to distinguish ones true friends from enemies because appearances are often deceptive and it is immoral and injustice to harm someone without proper inquiry.
The Theory of Thrasymachus (Radicalism)
Thrasymachus regards justice as the interests or the sovereign. Plato rejects on the basis that it leads to "Might is Right” which can be applied only in the forests and not in a human society.