"Wonder is the beginning of wisdom in learning from books as well as from nature."
"There are genuine mysteries in the world that mark the limits of human knowing and thinking. Wisdom is fortified, not destroyed, by understanding its limitations. Ignorance does not make a fool as surely as self-deception."
"A lecture has been well described as the process whereby the notes of the teacher become the notes of the student without passing through the mind of either."
"Is it too much to expect from the schools that they train their students not only to interpret but to criticize; that is, to discriminate what is sound from error and falsehood, to suspend judgement if they are not convinced, or to judge with reason if they agree or disagree?"