Johannes Kepler

1572–1630 · German mathematician and astronomer

Topics: learning, physics, mathematics

• Geometry has two great treasures: one is the Theorem of Phythagoras, the other the division of a line in extreme and mean ratio. The first we can compare to a mass of gold; the other we may call a precious jewel.

  — Johannes Kepler

• I reply in a single word to the sentiments of the saints on these questions about nature; in theology, to be sure, the force of authorities is to be weighed, in philosophy, however, that of causes

  — Johannes Kepler

• I was almost driven to madness in considering and calculating this matter. I could not find out why the planet would rather go on an elliptical orbit. Oh, ridiculous me!

  — Johannes Kepler

• Gravity is a mutual affection between cognate bodies towards union or conjunction (similar in kind to the magnetic virtue), so that the earth attracts a stone much rather than the stone seeks the earth.

  — Johannes Kepler

• Just as the eye was made to see colours, and the ear to hear sounds, so the human mind was made to understand, not whatever you please, but quantity.

  — Johannes Kepler

• If the earth were not round, heavy bodies would not tend from every side in a straight line towards the center of the earth, but to different points from different sides.

  — Johannes Kepler

• [W]ithout proper experiments I conclude nothing...

  — Johannes Kepler

• If the earth should cease to attract its waters to itself all the waters of the sea would be raised and would flow to the body of the moon.

  — Johannes Kepler