The study of science teaches young men to think, while study of the classics teaches them to express thought.

Almost all rich veins of original and striking speculation have been opened by systematic half-thinkers.

My father taught me that the question Who made me? cannot be answered, since it immediately suggests the further question, Who made God?

A cultivated mind is one to which the fountains of knowledge have been opened, and which has been taught, in any tolerable degree, to exercise its faculties.

Accordingly, France Had Voltaire, and his school of negative thinkers, and England (or rather Scotland) had the profoundest negative thinker on record, David Hume: a man, the peculiarities of whose mind qualified him to detect failure of proof, and want of logical consistency, at a depth which French skeptics, with their comparatively feeble powers of analysis and abstractions stop far short of, and which German subtlety alone could thoroughly appreciate, or hope to rival.

The pupil who is never required to do what he cannot do, never does what he can do.

The successful conduct of an industrial enterprise requires two quite distinct qualifications: fidelity and zeal.