I'm not contented to capture the world. I want to change it.
The memory of benefits is a frail defence against ingratitude.
No human investigation can claim to be scientific if it doesn't pass the test of mathematical proof.
Knowledge ... shall always bear witness like a clarion to its creator.
Those who are inspired by a model other than Nature, labor in vain.
A deaf and dumb person who sees two men in conversation - may nevertheless understand from the attitudes and gestures of the speakers, how well their discussion is getting along.