Love of play is the most obvious distinguishing mark of young animals, whether human or otherwise. In human children, this is accompanied by an inexhaustible pleasure in pretence. Play and pretence are a vital need of childhood, for which opportunity must be provided if the child is to be happy and healthy, quite independently of any further utility in these activities. There are two questions which concern education in this connection: first, what should parents and schools do in the way of providing opportunity? and secondly, should they do anything more, with a view to increasing the educational usefulness of games? Let us begin with a few words about the psychology of games. This has been exhaustively treated by Groos; a shorter discussion will be found in William Stern’s book mentioned in the preceding chapter. There are two separate questions in this matter: the first is as to the impulses which produce play, the second is as to its biological utility. The second is the easier question. There seems no reason to doubt the most widely accepted theory, that in play the young of any species rehearse and practise the activities which they will have to perform in earnest later on. The play of puppies is exactly like a dog-fight, except that they do not actually bite each other. The play of kittens resembles the behaviour of cats with mice. Children love to imitate any work they have been watching, such as building or digging; the more important the work seems to them, the more they like to play at it. And they enjoy anything that gives them new muscular facilities, such as jumping, climbing, or walking up a narrow plank--always provided the task is not too difficult. But although this accounts, in a general way, for the usefulness of the play-impulse, it does not by any means cover all its manifestations, and must not for a moment be regarded as giving a psychological analysis. Some psycho-analysts have tried to see a sexual symbolism in children’s play. This, I am convinced, is utter moonshine. The main instinctive urge of childhood is not sex, but the desire to become adult, or, perhaps more correctly, the will to power.[11] The child is impressed by his own weakness in comparison with older people, and he wishes to become their equal. I remember my boy’s profound delight when he realized that he would one day be a man and that I had once been a child; one could see effort being stimulated by the realization that success was possible. From a very early age, the child wishes to do what older people do, as is shown by the practice of imitation. Older brothers and sisters are useful, because their purposes can be understood and their capacities are not so far out of reach as those of grown-up people. The feeling of inferiority is very strong in children; when they are normal and rightly educated, it is a stimulus to effort, but if they are repressed it may become a source of unhappiness.