The chief aim of all investigations of the external world should be to discover the rational order and harmony which has been imposed on it by God and which He revealed to us in the language of mathematics.

Once miracles are admitted, every scientific explanation is out of the question.

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.

The squares of the periodic times are proportional to the cubes of the mean distances from the sun.

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.

It is a right, yes a duty, to search in cautious manner for the numbers, sizes, and weights, the norms for everything [God] has created. For He himself has let man take part in the knowledge of these things ... For these secrets are not of the kind whose research should be forbidden; rather they are set before our eyes like a mirror so that by examining them we observe to some extent the goodness and wisdom of the Creator.

If God himself has waited six thousand years for someone to contemplate his works, my book can wait for a hundred.