Boundaries which mark off one field of science from another are purely artificial, are set up only for temporary convenience. Let chemists and physicists dig deep enough, and they reach common ground.
Discovery begins by finding the discoverer.
A calculating engine is one of the most intricate forms of mechanism, a telegraph key one of the simplest. But compare their value.
Error held as truth has much the effect of truth. In politics and religion this fact upsets many confident predictions.
Some young folks have wind-fall minds, prematurely detached from the tree of knowledge for a life-long sourness and pettiness.
When a learner, in the fullness of his powers, comes to great truths unstaled by premature familiarity, he rejoices in the lateness of his lessons.
Nothing cools so fast as undue enthusiasm. Water that has boiled freezes sooner than any other.
We despair of changing the habits of men, still we would alter institutions, the habits of millions of men.
A tree nowhere offers a straight line or a regular curve, but who doubts that root, trunk, boughs, and leaves embody geometry?
No gun is perfectly true. So the marksman, that he may hit the bull's-eye, points elsewhere.
Truth is better disengaged from error than torn from it.
Ten builders rear an arch, each in turn lifting it higher; but it is the tenth man, who drops in the keystone, who hears our huzzas.
To render aid to the worthless is sheer waste. Rain does not freshen the Dead Sea, but only enables it to dissolve more salt.
They will listen with both ears to what is said by the men just a step or two ahead of them, who stand nearest to them, and within arm's reach. A guide ceases to be of any use when he strides so far ahead as to be hidden by the curvature of the earth.
Dumbness and silence are two different things.
A superstition is a premature explanation that overstays its time.
Doubt is the beginning, not the end, of wisdom.
A man's own addition to what he learns is cement to bind an otherwise loose heap of stones into a structure of unity, strength, and use.
Ignorance may find a truth on its doorstep that erudition vainly seeks in the stars.