Plato's Republic: the argument with Polemarchus.--Plato's Republic: the argument with Thrasymachus.--Plato's Republic: the nature of the soul.--Plato's Republic: the comparison between the soul and the state.--Plato's Republic: the proof that the most just man is the happiest.--Aristotle's definition of moral virtue and Plato's account of justice in the soul.--Purposive action.--A comparison of Kant's idealism with that of Berkeley.--The syntheses of sense and understanding in Kant's Kritik of pure reason.--The schematism of the categories in Kant's Kritik of pure reason.--The concept of evolution.