Some of what these pamphlets [of astrological forecasts] say will turn out to be true, but most of it time and experience will expose as empty and worthless. The latter part will be forgotten literally: written on the winds while the former will be carefully entered in people's memories, as is usual with the crowd.

There will certainly be no lack of human pioneers when we have mastered the art of flight....Let us create vessels and sails justed to the heavenly ether, and there will be plenty of people unafraid of the empty wastes. In the meantime we shall prepare, for the brave sky-travelers, maps of the celestial bodies.

When things are in order, if the cause of the orderliness cannot be deduced from the motion of the elements or from the composition of matter, it is quite possibly a cause possessing a mind.

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

Why are things as they are and not otherwise?

Where there is matter, there is geometry.

The sun alone appears, by virtue of his dignity and power, suited for this motive duty (of moving the planets) and worthy to become the home of God himself.