Returning to the elements of truth contained in Rousseau's statements, we find that natural development, as an aim, enables him to point the means of correcting many evils in current practices, and to indicate a number of desirable specific aims. (1) Natural development as an aim fixes attention upon the bodily organs and the need of health and vigor. The aim of natural development says to parents and teachers: Make health an aim; normal development cannot be had without regard to the vigor of the body--an obvious enough fact and yet one whose due recognition in practice would almost automatically revolutionize many of our educational practices. "Nature" is indeed a vague and metaphorical term, but one thing that "Nature" may be said to utter is that there are conditions of educational efficiency, and that till we have learned what these conditions are and have learned to make our practices accord with them, the noblest and most ideal of our aims are doomed to suffer--are verbal and sentimental rather than efficacious. (2) The aim of natural development translates into the aim of respect for physical mobility. In Rousseau's words: "Children are always in motion; a sedentary life is injurious." When he says that "Nature's intention is to strengthen the body before exercising the mind" he hardly states the fact fairly. But if he had said that nature's "intention" (to adopt his poetical form of speech) is to develop the mind especially by exercise of the muscles of the body he would have stated a positive fact. In other words, the aim of following nature means, in the concrete, regard for the actual part played by use of the bodily organs in explorations, in handling of materials, in plays and games. (3) The general aim translates into the aim of regard for individual differences among children. Nobody can take the principle of consideration of native powers into account without being struck by the fact that these powers differ in different individuals. The difference applies not merely to their intensity, but even more to their quality and arrangement. As Rouseau said: "Each individual is born with a distinctive temperament. We indiscriminately employ children of different bents on the same exercises; their education destroys the special bent and leaves a dull uniformity. Therefore after we have wasted our efforts in stunting the true gifts of nature we see the short-lived and illusory brilliance we have substituted die away, while the natural abilities we have crushed do not revive."