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.

The Universe is a grand book which cannot be read until one first learns to comprehend the language and become familiar with the characters in which it is composed. It is written in the language of mathematics.

I therefore concluded, and decided unhesitatingly, that there are three stars in the heavens moving about Jupiter, as Venus and Mercury about the Sun; which at length was established as clear as daylight by numerous other observations.

Science proceeds more by what it has learned to ignore than what it takes into account.

By denying scientific principles, one may maintain any paradox.

Philosophy itself cannot but benefit from our disputes, for if our conceptions prove true, new achievements will be made; if false, their refutation will further confirm the original doctrines.