The founder of the Academy gave a lecture "On the Good." Most of Plato’s audience came expecting to be told how to get rich, or stay healthy, or be happy, and were disappointed to hear a lecture full of mathematics, culminating in the statement that the Good is One. Its practical implications were not immediate.

Philosophy is more vulnerable than natural science to the populist belief that laypeople are just as qualified as professionals. This belief derives from the ideal of the radically autonomous inquirer, who takes nothing for granted and uses nothing second-hand. In other words, such a thinker refuses to learn anything from other people. That’s a recipe for the endless repetition of the same elementary mistakes, generation after generation. Anyway, the instructions cannot be carried out; all thinking takes much for granted. The ideal of the radically autonomous inquirer is itself stale and nth-hand.

I’ll never concede to them that the rich man can become really happy without being virtuous as well: to be extremely virtuous and exceptionally rich at the same time is absolutely out of the question. ‘Why?’ it may be asked. ‘Because,’ we shall reply, ‘the profit from using just and unjust methods is more than twice as much as that from just methods alone, and a man who refuses to spend his money either worthily or shamefully spends only half the sum laid out by worthwhile people who are prepared to spend on worthy purposes too. So anyone who follows the opposite policy will never become richer than the man who gets twice as much profit and makes half the expenditures. The former is a good man; the latter is not actually a rogue so long as he uses his money sparingly, but on some occasions he is an absolute villain; thus, as we have said, he is never good. Ill-gotten and well-gotten gains plus expenditure that is neither just nor unjust, when a man is also sparing with his money, add up to wealth; the absolute rogue, who is generally a spendthrift, is quite impoverished. The man who spends his money for honest ends and uses only just methods to come by it, will not easily become particularly rich or particularly poor. Our thesis is therefore correct: the very rich are not good; and if they are not good, they are not happy either.’