To avoid a split between what men consciously know because they are aware of having learned it by a specific job of learning, and what they unconsciously know because they have absorbed it in the formation of their characters by intercourse with others, becomes an increasingly delicate task with every development of special schooling.

In the present state of the world, it is evident that the control we have gained of physical energies, heat, light, electricity, etc., without having first secured control of our use of ourselves is a perilous affair. Without the control of our use of ourselves, our use of other things is blind; it may lead to anything.

The path of least resistance and least trouble is a mental rut already made. It requires troublesome work to undertake the alternation of old beliefs. Self-conceit often regards it as a sign of weakness to admit that a belief to which we have once committed ourselves is wrong. We get so identified with an idea that it is literally a pet notion and we rise to its defense and stop our eyes and ears to anything different.

Teaching may be compared to selling commodities. No one can sell unless somebody buys.

A man really living alone (alone mentally as well as physically) would have little or no occasion to reflect upon his past experience to extract its net meaning.

All of us have many habits of whose import we are quite unaware, since they were formed without our knowing what we were about. Consequently they possess us, rather than we them. They move us; they control us. Unless we become aware of what they accomplish, and pass judgment upon the worth of the result, we do not control them.

Scientific principles and laws do not lie on the surface of nature. They are hidden, and must be wrested from nature by an active and elaborate technique of inquiry.