ABSTRACT
Rational human beings living as part and parcel of animate nature have always known a great deal about and have accepted evolution quite independently of any formal theory of evolution. Our mode of treatment, which may be characterized as that of comparative psychobiology, involves an assumption of the kinship of man with the rest of the living world, and of an especially close kinship with the upper levels of the animal world. An aspect of the evolution problem which adds to its complication both in its phenomenal phase, and in its psychological-logical phase is the difficulty of including in our conception of an organism the potentiality or latent capacity which every organism has in any one of its developmental stages to pass into the next stage. Common knowledge accepts evolution as the mode of the origin of individual men and all other organisms, animal and plant.
