The attempt to construct moral codes on the basis of an inventory is an attempt to understand something which is always in process of change by treating it as a still life and taking snapshots of it. That is what moralists have almost always attempted to do. They have tried to capture the essence of a changing thing in a collection [p171] of fixed concepts. It cannot be done. The reality of human nature is bound to elude us if we look only at a momentary cross-section of it. To understand it, therefore, for the purposes of moralizing, we have to revise our intellectual apparatus, and learn to look upon each moment of behavior not as the manifestation of certain fixed elements in human nature, but as a stage in the evolution of human nature. We grow up, mature, and decline; being endowed with memory and the capacity to form habits, our conduct is cumulative. We drag our past along with us and it pushes us on. We do not make a new approach to each new experience. We approach new experiences with the expectations and habits developed by previous experience, and under the impact of novelty these expectations and habits become modified. 6. _The Matrix of Humanism_ The conception of human nature as developing behavior is, of course, accepted by all modern psychologists. If they study the child they are bound to consider him as potentially an adult. If they study the adult they are bound to regard him as originally a child. Abnormal psychology makes sense only insofar as it can be understood as an abnormal development of the personality, regardless of whether that abnormality is traceable to pre-natal variations, to organic disease, or to functional disturbance. Folk psychology, whether or not one accepts the interesting but speculative hypothesis that there is a parallel between the development of the individual and the development of the race, is another mode of investigating the evolution of behavior. The concept of development [p172] is thoroughly established in psychology as the major clue to the understanding of human nature.