Learning is the ally, not the adversary of genius... he who reads in a proper spirit, can scarcely read too much.

Books are the depositary of everything that is most honourable to man.

Invisible things are the only realities; invisible things alone are the things that shall remain.

No man must encroach upon my province, nor I upon his. He may advise me, moderately and without pertinaciousness, but he must not expect to dictate to me. He may censure me freely and without reserve; but he should remember that I am to act by my deliberation and not his. I ought to exercise my talents for the benefit of others; but that exercise must be the fruit of my own conviction; no man must attempt to press me into the service.

What can be more clear and sound in explanation, than the love of a parent to his child?

The subtleties of mathematics defecate the grossness of our apprehension, and supply the elements of a sounder and severer logic.

There must be room for the imagination to exercise its powers; we must conceive and apprehend a thousand things which we do not actually witness.