THE REPUBLIC: BY PLATO (428BC-347BC)

....Why do men behave justly ?
Is it because they fear societal punishment? Are they trembling before notions of divine retribution? Do the stronger elements of society scare the weak into submission in the name of law?

....Socrates asks permission to backtrack a little at the opening of Book VIII in order to analyze the forms of corrupt governments. This way they can also look at the individuals inhabiting them, thus cutting away the grist so that only the meat, the just man, may remain. There are four principle defective forms: timocracy, oligarchy, democracy, and tyranny. Aristocracy's (the republic) degeneration into timocracy occurs as a kind of hypothetical fluke, an error in population control. The timocracy is a government based primarily on honor not justice, and the timocratic man is torn between his philosophical ancestors and new, ingratiating contemporaries who flatter his vanity. Oligarchy arises when wealth becomes the standard. The State separates into two distinct and distant classes‹rich and poor. And the timocrat embodies the old, honorable ways in competition with avarice. After a revolution in which the rulers are overthrown by the discontented poor, democracy, the most liberal and various State appears. The democratic representative is ruled by appetites that hold sway well above reason or honor. The final dissolution into the worst and most wicked form of government, tyranny, is the result of democracy's supposed virtue: freedom. But is in excess and, after another revolution, a new ruler, the tyrant ascends. He has no unlimited freedom and thus no morals. He feels off the State, taxes his people, protects himself with mercenaries, and destroys any threat to this power. The book's most miserable character, the tyrant is antithetical to the guardian; he is injustice incarnate.

....The form of government Socrates points out, the human tendency, to corruption by power and thus the road to timocracy, oligarchy, democracy and tyranny: concluding that ruling should be left to philosophers, the most just and therefore least susceptible to corruption.