Psychology is the science of the intellects, characters and behavior of animals including man.

Human beings are accustomed to think of intellect as the power of having and controlling ideas and of ability to learn as synonymous with ability to have ideas. But learning by having ideas is really one of the rare and isolated events in nature.

The restriction of studies of human intellect and character to studies of conscious states was not without influence on a scientific studies of animal psychology.

The un-conscious distortion of the facts is almost harmless compared to the unconscious neglect of an animal's mental life until it verges on the unusual and marvelous.

So the animal finally performs in that situation only the fitting act.

All that exists, exists in some amount and can be measured.

Psychology is the science of the intellects, characters and behavior of animals including man.