" (p. 55) Socrates doesn't argue the point during that discussion but expresses his concern. He later gives many examples to illustrate why morality and justice are more beneficial. However he doesn't specifically answer the argument that given a chance, everyone would sin. Socrates however makes it clear that a man with a moral sense deeply embedded in him wouldn't commit sin even if he were to remain invisible from his fellows because he knows that morality has greater rewards. This person is moved by the inner conviction that morality is indeed as good as God makes it sound. He therefore sticks to moral actions in order to please the God and to get ample rewards. "...morality does have the reputation it enjoys among gods and men. We've found that actually being moral entails benefits..." (p. 369)

Socrates is a suitable person for making this argument because he remained just even when he had a chance to commit injustice. In the Apology, we learn that Socrates was offered a choice that could lead to a life in exile but would have saved his life. Socrates...

till the very end, Socrates remained true to his moral sense and thus it won't be wrong to counter the previous argument by saying that visibility or invisibility are not the issue and those who have a strong inner moral compass are more inclined to do justice even when no one is looking.
At the back of our minds, if we accept that morality has greater benefits, then we are more likely to follow that path in tricky situations. However a person who doesn't accept the benefits accruing from justice would be greatly inclined to commit acts of immorality as and when an opportunity arises. It is more about acceptance and conviction. One doesn't really need to constantly be afraid of being caught in order to do justice. If he only keeps in mind the long-term benefits, he will choose the path of justice instead of injustice under all circumstances.

Works Cited

Plato, Republic, trans. Robin Waterfield (Oxford: Oxford University Press, 1994)