Social laughter is momentary, soon burns itself out and passes away like the fire and smokes of straw, but genius shakes the very skies with its lasting, inextinguishable laughter.

The psycho-physiological hypothesis is both inductively and deductively the sine qua non of the science of psychology.

Psychology must postulate uniformity of interrelation of physical, physiological, and psychic processes.

Suggestibility varies as the amount of disaggregation, and inversely as the unification of consciousness.

The principle of recognition of evil under all its guises is at the basis of the true education of man.

Self-preservation is the central aim of all life-activities.

The general tendency of evolution is from structure to function, from bondage to freedom of the individual elements.