The life of the mind is the life of pursuit of knowledge, from mere childish curiosity up to the greatest efforts of thought. Curiosity exists in animals, and serves an obvious biological purpose; but it is only in men that it passes beyond the investigation of particular objects which may be edible or poisonous, friendly or hostile. Curiosity is the primary impulse out of which the whole edifice of scientific knowledge has grown. Knowledge has been found so useful that most actual acquisition of it is no longer prompted by curiosity; innumerable other motives now contribute to foster the intellectual life. Nevertheless, direct love of knowledge and dislike of error still play a very large part, especially with those who are most successful in learning. No man acquires much knowledge unless the acquisition is in itself delightful to him, apart from any consciousness of the use to which the knowledge may be put. The impulse to acquire knowledge and the activities which center round it constitute what I mean by the life of the mind. The life of the mind consists of thought which is wholly or partially impersonal, in the sense that it concerns itself with objects on their own account, and not merely on account of their bearing upon our instinctive life. The life of the spirit centers round impersonal feeling, as the life of the mind centers round impersonal thought. In this sense, all art belongs to the life of the spirit, though its greatness is derived from its being also intimately bound up with the life of instinct. Art starts from instinct and rises into the region of the spirit; religion starts from the spirit and endeavors to dominate and inform the life of instinct. It is possible to feel the same interest in the joys and sorrows of others as in our own, to love and hate independently of all relation to ourselves, to care about the destiny of man and the development of the universe without a thought that we are personally involved. Reverence and worship, the sense of an obligation to mankind, the feeling of imperativeness and acting under orders which traditional religion has interpreted as Divine inspiration, all belong to the life of the spirit. And deeper than all these lies the sense of a mystery half revealed, of a hidden wisdom and glory, of a transfiguring vision in which common things lose their solid importance and become a thin veil behind which the ultimate truth of the world is dimly seen. It is such feelings that are the source of religion, and if they were to die most of what is best would vanish out of life.