So long as the mother, Ignorance, lives, it is not safe for Science the offspring, to divulge the hidden causes of things.

A most unfailing experience... of the excitement of sublunary (that is, human) natures by the conjunctions and aspects of the planets has instructed and compelled my unwilling belief.

When ships to sail the void between the stars have been built, there will step forth men to sail these ships.

Astronomy would not provide me with bread if men did not entertain hopes of reading the future in the heavens.

God gives every animal the means of saving its life-why object if he gives astrology to the astronomer?

O telescope, instrument of much knowledge, more precious than any sceptre!

Do we ask what profit the little bird hopes for in singing?

Eyesight should learn from reason.

The most true path of the planet Mars is an ellipse, which Dürer also calls an oval, or certainly so close to an ellipse that the difference is insensible.

I had the intention of becoming a theologian...but now I see how God is, by my endeavors, also glorified in astronomy, for 'the heavens declare the glory of God.'

I used to measure the Heavens, now I measure the shadows of Earth. The mind belonged to Heaven, the body's shadow lies here.

I am a Lutheran astrologer, I throw away the nonsense and keep the hard kernel.

Science is the process of thinking God's thoughts after Him.

Truth is the daughter of time, and I feel no shame in being her midwife.

Repudiating the sensible world, which he neither sees himself nor believes from those who have, the Peripatetic joins combat by childish quibbling in a world on paper, and denies the Sun shines because he himself is blind.

Since geometry is co-eternal with the divine mind before the birth of things, God himself served as his own model in creating the world (for what is there in God which is not God?), and he with his own image reached down to humanity.

Geometry existed before the creation. It is co-eternal with the mind of God...Geometry provided God with a model for the Creation.

If the moon and earth were not retained in their orbits by their animal force or some other equivalent, the earth would mount to the moon by a fifty-fourth part of their distance, and the moon fall towards the earth through the other fifty-three parts, and they would there meet, assuming, however, that the substance of both is of the same density.

If my false figures came near to the facts, this happened merely by chance ... These comments are not worth printing. Yet it gives me pleasure to remember how many detours I had to make, along how many walls I had to grope in the darkness of my ignorance until I found the door which lets in the light of the truth ... In such manner did I dream of the truth.

Ships and sails proper for the heavenly air should be fashioned. Then there will also be people, who do not shrink from the dreary vastness of space.