Psychology helps to measure the probability that an aim is attainable.

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

Just as the science and art of agriculture depend upon chemistry and botany, so the art of education depends upon physiology and psychology.

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.

Fight for your highest attainable aim/ But never put up resistance in vain.

This growth in the number, speed of formation, permanence, delicacy and complexity of associations possible for an animal reaches its acme in the case of man.