Galileo Galilei

Witty retort to critics.

The profound silence of space.

Interesting fact: comets are illusions.

Notable: the double star system.

Every motion has a cause.

Profound: the unity of nature.

Interesting: the hydrostatic balance.

I do not feel obliged to believe that the same God who has endowed us with senses, reason, and intellect has intended us to forgo their use.

Mathematics is the language in which God has written the universe.

Eppur si muove! (And yet it moves!)

I think that in the discussion of natural problems, we ought not to begin at the authority of passages of Scripture, but at sensible experiments and necessary demonstrations.

It is surely harmful to souls to make it a heresy to believe what has been proved.

Philosophy is written in this grand book, the universe, which stands continually open to our gaze. But the book cannot be understood unless one first learns to comprehend the language and interpret the characters in which it is written. It is written in the language of mathematics, and its characters are triangles, circles, and other geometric figures, without which it is humanly impossible to understand a single word of it; without these, one is wandering about in a dark labyrinth.

To understand the universe, you must understand the language in which it's written: mathematics.

Facts which at first seem improbable will, even in scant explanation, drop the cloak which has hidden them and stand forth in naked and simple beauty.

Nature is relentless and unchangeable, and it is indifferent as to whether its hidden reasons and actions are understandable to man or not.

It is a beautiful and admirable thing to observe how the human mind, when it is applied to the investigation of truth, is able to penetrate the most hidden secrets of nature.

The senses, being the interpreters of natural effects, are the only true guides to the knowledge of nature.

The greatest wisdom is to know that we know nothing.

I give infinite thanks to God, who has been pleased to make me the first observer of admirable things unrevealed to past ages.