Two truths cannot contradict one another.

In the sciences, the authority of thousands of opinions is not worth as much as one tiny spark of reason in an individual man.

I have never met a man so ignorant that I couldn't learn something from him.

Measure what is measurable, and make measurable what is not so.

Two truths cannot contradict one another.

The surface of the Moon is not smooth, uniform, and precisely spherical as a great number of philosophers believe it to be, but is uneven, rough, and full of cavities and prominences, being not unlike the face of the Earth, relieved by chains of mountains and deep valleys.

Nature...does not act by means of many things when it can do so by means of a few.