The vices respectively fall short of or exceed what is right in both passions and actions, while virtue both finds and chooses that which is intermediate.
The investigation of the truth is in one way hard, in another easy. An indication of this is found in the fact that no one is able to attain the truth adequately, while, on the other hand, no one fails entirely, but everyone says something true about the nature of all things, and while individually they contribute little or nothing to the truth, by the union of all a considerable amount is amassed.
Some vices miss what is right because they are deficient, others because they are excessive, in feelings or in actions, while virtue finds and chooses the mean.
What the statesman is most anxious to produce is a certain moral character in his fellow citizens, namely a disposition to virtue and the performance of virtuous actions.
Opinion involves belief (for without belief in what we opine we cannot have an opinion), and in the brutes though we often find imagination we never find belief.