Men habitually use only a small part of the power which they actually possess.

Most people live, whether physically, intellectually or morally, in a very restricted circle of their potential being. They make very small use of their possible consciousness, and of their soul's resources in general, much like a man who, out of his whole bodily organism, should get into a habit of using and moving only his little finger.

Every man who possibly can should force himself to a holiday of a full month in a year, whether he feels like taking it or not.

Wisdom is learning what to overlook.

Theory must mediate between all previous truths and certain new experiences

To study the abnormal is the best way of understanding the normal.

The worst thing that can happen to a good teacher is to get a bad conscience about her profession because she feels herself hopeless as a psychologist.