Ignorance, when voluntary, is criminal, and a man may be properly charged with that evil which he neglected or refused to learn how to prevent.

Integrity without knowledge is weak and useless, and knowledge without integrity is dangerous and dreadful.

Mankind have a great aversion to intellectual labor; but even supposing knowledge to be easily attainable, more people would be content to be ignorant than would take even a little trouble to acquire it.

Knowledge is of two kinds. We know a subject ourselves, or we know where we can find information upon it. When we enquire into any subject, the first thing we have to do is to know what books have treated of it. This leads us to look at catalogues, and at the backs of books in libraries.

There is nothing so minute or inconsiderable that I would not rather know it than not know it.

To talk in public, to think in solitude, to read and to hear, to enquire and answer enquiries, is the business of a scholar. He wanders about the world without pomp or terror, and is neither known nor valued but by men like himself.

The seeds of knowledge may be planted in solitude, but must be cultivated in public.

Knowledge always desires increase, it is like fire, which must first be kindled by some external agent, but which will afterwards propagate itself.

To understand the works of celebrated authors, to comprehend their systems, and retain their reasonings, is a task more than equal to common intellects; and he is by no means to be accounted useless or idle, who has stored his mind with acquired knowledge, and can detail it occasionally to others who have less leisure or weaker abilities.