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.

Evolution pays and that is why there is evolution

To render aid to the worthless is sheer waste. Rain does not freshen the Dead Sea, but only enables it to dissolve more salt.

Let truth be a banner big enough to hide the man who holds it up.

A calculating engine is one of the most intricate forms of mechanism, a telegraph key one of the simplest. But compare their value.

A tree nowhere offers a straight line or a regular curve, but who doubts that root, trunk, boughs, and leaves embody geometry?

Doubt is the beginning, not the end, of wisdom.