Nothing occurs contrary to nature except the impossible, and that never occurs.

If you could see the earth illuminated when you were in a place as dark as night, it would look to you more splendid than the moon.

It vexes me when they would constrain science by the authority of the Scriptures, and yet do not consider themselves bound to answer reason and experiment.

And believe me, if I were again beginning my studies, I should follow the advice of Plato and start with the mathematical sciences, which proceed very cautiously and admit nothing as established until it has been rigorously demonstrated.

Measure what can be measured, and make measureable what cannot be measured.

To understand the Universe, you must understand the language in which it's written, the language of Mathematics.

The Grand Duke [of Tuscany] ...after observing the Medicaean plants several times with me ... has now invited me to attach myself to him with the annual salary of one thousand florins, and with the title of Philosopher and Principal Mathematicial to His Highness; without the duties of office to perform, but with the most complete leisure; so that I can complete my Treatises.