The concept of value has its most direct and obvious application in the realm of human action and character. Thoughts on these matters develop into the issues in ethics and political theory that occupied Plato and have continued to be debated over the long centuries. In some philosophies (examples are the Stoics, the Neoplatonists, Gottfried Leibniz, George Berkeley) value is also contemplated in cosmic or metaphysical terms, where it is the goodness not of humans specifically but of the universe and the nature of things that is under consideration. Plato discusses value in both these contexts and regards them as closely related.

THE SOCRATIC PARADOXES AND MORAL PHILOSOPHY

Socrates is associated with a number of paradoxes concerning virtue. These are that virtue is single, that virtue is knowledge, and that no one does wrong willingly. These claims are closely connected, with each of them depending on assigning a central place to knowledge in the prescription for the good life. Plato investigates different facets of the good life in various works; but the one theme that runs through all his discussion is that without knowledge of what it is best to do, there is no guarantee that any other aspect of life – power, inheritance, environment – will deliver a good result. Conversely there is nothing that can prevent a person who has such knowledge from acting well.