ABSTRACT
This chapter argues that the psychologist should and must choose the fundamental categories appropriate to his science, if he is to make progress toward his proper goal, the better understanding and control of human nature and human behavior. It also provides the various marks of behaviour. The principle of the tropism has been confidently offered as adequate to explain the lower sub-reflex forms of behavior. The study of animal behavior teaches different lessons of high importance for psychology some of them are: It makes clearer the nature of purposive action and reveals its prevalence throughout the whole of the animal world. It eidates the very foundations of human nature, by displaying in relative simplicity among the animals the modes of action which are fundamental in human behavior, but which in human life are so complicated and obscured by the great development of our intellectual powers that their full importance is only now beginning to be recognized.
