Vitality is rather a physiological than a mental characteristic; it is presumably always present where there is perfect health, but it tends to ebb with advancing years, and gradually dwindles to nothing in old age. In vigorous children it quickly rises to a maximum before they reach school age, and then tends to be diminished by education. Where it exists, there is pleasure in feeling alive, quite apart from any specific pleasant circumstance. It heightens pleasures and diminishes pains. It makes it easy to take an interest in whatever occurs, and thus promotes objectivity, which is an essential of sanity. Human beings are prone to become absorbed in themselves, unable to be interested in what they see and hear or in anything outside their own skins. This is a great misfortune to themselves, since it entails at best boredom and at worst melancholia; it is also a fatal barrier to usefulness, except in very exceptional cases. Vitality promotes interest in the outside world; it also promotes the power of hard work. Moreover it is a safeguard against envy, because it makes one’s own existence pleasant. As envy is one of the great sources of human misery, this is a very important merit in vitality. Many bad qualities are of course compatible with vitality--for example, those of a healthy tiger. And many of the best qualities are compatible with its absence: Newton and Locke, for example, had very little. Both these men, however, had irritabilities and envies from which better health would have set them free. Probably the whole of Newton’s controversy with Leibniz, which ruined English mathematics for over a hundred years, would have been avoided if Newton had been robust and able to enjoy ordinary pleasures. In spite of its limitations, therefore, I reckon vitality among the qualities which it is important that all men should possess. Courage--the second quality on our list--has several forms, and all of them are complex. Absence of fear is one thing, and the power of controlling fear is another. And absence of fear, in turn, is one thing when the fear is rational, another when it is irrational. Absence of irrational fear is clearly good; so is the power of controlling fear. But absence of rational fear is a matter as to which debate is possible. However, I shall postpone this question until I have said something about the other forms of courage.