It is just that we should be grateful, not only to those with whose views we may agree, but also to those who have expressed more superficial views; for these also contributed something, by developing before us the powers of thought.
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.
The life of theoretical philosophy is the best and happiest a man can lead. Few men are capable of it and then only intermittently. For the rest there is a second-best way of life, that of moral virtue and practical wisdom.