In book two of Plato's The Republic, Glaucon provides us with an extensive theory of justice. For Glaucon, you can't have justice without injustice. If you want to discuss justice, we need to talk about injustice. Justice, in a sense, stems from injustice.

Glaucon posits that most humans would live an unjust life if they could. It's basically too tempting and too intoxicating to resist. "Injustice is far more profitable to the individual than justice," claims Glaucon.

To prove his theory, Glaucon tells about Gyges and his magical ring. The ring renders Gyges invisible. What does he do with this superpower-like ability? He commits injustice. He seduces the queen. Together, they kill the king. What happens next? According to Glaucon, Gyges "took the kingdom."

What does the above have to do with justice and injustice? It shows that minus the fear of justice, injustice would rein supreme. Glaucon argues that any person who possessed the powers of Gyges and didn’t commit a cascade of injustices would be “a most wretched idiot.” Yet Glaucon admits that people would “praise him” in public.

For Glaucon, the "best of all" is to commit injustice with impunity. Conversely, the "worse of all" is "to suffer injustice without the power of retaliation." Justice appears as a middle point between the two extremes. It's like a compromise. It is, says Glaucon, "the lesser evil."

You might think about the consequences of Glaucon's definition of justice. Does it present a favorable or unfavorable view of human nature? What happens if justice itself becomes a kind of injustice? Think about the justice system in the United States. Is that justice or injustice?