The greatest and saddest defect is not credulity, but an habitual forgetfulness that our science is ignorance.

There is not one kind of food for all men. You must and you will feed those faculties which you exercise. The laborer whose body is weary does not require the same food with the scholar whose brain is weary.

Law never made men a whit more just; and, by means of their respect for it, even the well-disposed are daily made the agents of injustice.

As a true patriot, I should be ashamed to think that Adam in paradise was more favorably situated on the whole than the backwoodsman in this country.

if i repent of anything, it is very likely to be my good behavior. what demon possessed me that i behaved so well?

He is not a true man of science who does not bring some sympathy to his studies, and expect to learn something by behavior as well as by application. It is childish to rest in the discovery of mere coincidences, or of partial and extraneous laws. The study of geometry is a petty and idle exercise of the mind, if it is applied to no larger system than the starry one. Mathematics should be mixed not only with physics but with ethics; that is mixed mathematics. The fact which interests us most is the life of the naturalist. The purest science is still biographical.

The coward wants resolution, which the brave man can do without. He recognizes no faith above a creed, thinking this straw by which he is moored does him good service, because his sheet anchor does not drag.