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

A mind is accustomed to mathematical deduction, when confronted with the faulty foundations of astrology, resists a long, long time, like an obstinate mule, until compelled by beating and curses to put its foot into that dirty puddle.

I much prefer the sharpest criticism of a single intelligent man to the thoughtless approval of the masses.

The roads by which men arrive at their insights into celestial matters seem to me almost as worthy of wonder as those matters in themselves.

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.

The wisdom of the Lord is infinite as are also His glory and His power. Ye heavens, sing His praises; sun, moon, and planets, glorify Him in your ineffable language! Praise Him, celestial harmonies, and all ye who can comprehend them! And thou, my soul, praise thy Creator! It is by Him and in Him that all exist.

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