Teaching can be compared to selling commodities. No one can sell unless someone buys ... yet there are teachers who think they have done a good day's teaching irrespective of what the pupils have learned.

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.

Forty years spent in wandering in a wilderness like that of the present is not a sad fate - unless one attempts to make himself believe that the wilderness is after all itself the promised land.

Social engaged intellectuals must accept reality as they found it and shape it toward positive social goals, not stand aside in self-righteous isolation.

In general, every stimulus directs activity. It does not simply excite it or stir it up, but directs it toward an object.

The origin of thinking is some perplexity, confusion or doubt.

The scientific-religious conflict ultimately is a conflict between allegiance to this method and allegiance to even an irreducible minimum of belief so fixed in advance that it can never be modified.