Thrasymachus was a Greek sophist born in Chalcedon who was active in the late 5th century BCE. In Plato's Republic, he argues that justice is nothing more than the advantage of the stronger or ruler, and that the just person is simply obedient to the laws of the state, which are designed to benefit the ruler. Thrasymachus claims injustice or acting in one's own self-interest is more beneficial than justice. He believes rulers cannot make mistakes in lawmaking as might makes right.