“I am certainly interested in a tribunal in which, for having used my reason, I was deemed little less than a heretic.”

Philosophy is written in this grand book, the universe, which stands continually open to our gaze.

We see only the simple motion of descent, since that other circular one common to the Earth, the tower, and ourselves remains imperceptible.

What greater stupidity can be imagined than that of calling jewels, silver, and gold “precious,” and earth and soil “base”?

I do not know what to say in a case so surprising, so unlooked for and so novel.

I entertain no doubts as to the truth of the transfinites, which I have recognized with God’s help.

The Bible shows the way to go to heaven, not the way the heavens go.

The Milky Way is nothing else but a mass of innumerable stars planted together in clusters.

You can’t teach anybody anything, only make them realize the answers are already inside them.

Holy Writ was intended to teach men how to go to Heaven not how the heavens go.

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.

I believe that the intention of Holy Writ was to persuade men of the truths necessary to salvation; such as neither science nor other means could render credible, but only the voice of the Holy Spirit.

I give infinite thanks to God, who has been pleased to make me the first observer of marvelous things.

We must say that there are as many squares as there are numbers.

If I were again beginning my studies, I would follow the advice of Plato and start with mathematics.

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

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.