Galileo Galilei

The universe is written in the language of mathematics and its characters are triangles, circles and other geometric figures.

I think that in the discussion of natural problems we ought to begin not with the Scriptures, but with experiments, and demonstrations.

In the judgment of the law of nature, a man is always an accomplice of his own crimes.

The prohibition of science would be contrary to the commands of God.

To command the professors of astronomy to confute their own observations is to command them not to see what they see and not to understand what they know.

Nothing physical which sense-experience sets before our eyes, or which necessary demonstrations prove to us, ought to be called into question (much less condemned) upon the testimony of biblical passages.

The intention of the Holy Ghost is to teach us how one goes to heaven, not how heaven goes.

Parole non udite, ma perfette si vedde le sue azioni in tal segno che non si lasciano addurre a dire, ma fanno dire a gli altri che le veggiono.

Wine is sunlight, held together by water.

The nobility of man is his capacity to reach the stars.

I abhor the man who on frivolous pretense will ignore the use of that divine instrument the telescope.

Nature is relentless and unchangeable, and it is indifferent as to whether its hidden reasons and actions shall be discovered or hidden.

The greatest tragedy for a scientist is to observe the universe without being able to explain it.

By denying scientific principles, one may maintain any paradox.

Simplicity is the keynote of all true science.

The Milky Way is nothing else but a mass of innumerable stars, like the stars we see.

I wish, my dear Kepler, that we could have one hearty laugh together.

There are those who reason well, but are so prejudiced they do not even notice it.

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

The habit of an opinion often injures the reason.