Man has three kinds of power. Each is independent in its nature, and each has its own laws and composition. But the sources of their formation are the same.
The first power is what is called physical power. Its quantity and quality depend on the structure and tissues of the human machine.
The second power is called psychic power. Its quality depends on a man’s thinking center and the material it contains. What is called “will” and other similar things are functions of this power.
The third is called moral power. It depends on education and heredity.
The first two can easily be changed for they are easily formed. Moral power, on the other hand, is very hard to change, for it takes a long time to form.
If a man has common sense and sound logic, any action may change his opinion and his “will.” But changing his nature, that is, his moral make-up, needs prolonged pressure. ~ G