What role, according to Aristotle, does knowledge play in the exercise of the virtues of character? This is a simple question to ask, but a difficult one to answer simply. In order to answer this question, we have to tackle an elliptical passage in Nicomachean Ethics II.4, which is part of Aristotle’s solution to a different puzzle about virtuous action.
That puzzle is (very roughly) this: if we have to do the virtuous thing in order to become virtuous, but we have to be virtuous in order to do the virtuous thing, how do we ever get started? Aristotle notes that we talk about actions and corresponding states of soul in two different ways, (let’s label them) logically – the actions accord with a certain state – and causally – the actions are the product of that state. So, too, with virtue: there are actions that are courageous because they are what a courageous person would do and actions that are courageous because they flow from the courageous person’s courage. Puzzle solved: when we’re on the way to virtue, we have to do the first kind of action so that when we acquire virtue, we are capable of the second.
Where the terrain gets treacherous is when Aristotle decides to try to characterize the state of the soul that differentiates the latter from the former case: