Nicolaus Copernicus

For I am not so much enamored of my own opinions that I would disregard what others may think of them.

Perhaps there will be babblers who, although completely ignorant of mathematics, nevertheless dare to pass judgment on these things, and because of some passage of Scripture, twisted to their purpose, will presume to condemn and censure my project. I pay them no heed.

For it is the duty of an astronomer to compose the history of the celestial motions from careful and expert study.

The motion of the Earth is a necessary consequence of the fact that the Sun is the center of the universe.

Therefore, when I had long considered this uncertainty of the traditional mathematical doctrines concerning the ordering of the spheres of the world, I began to be annoyed that no more accurate explanation of the movement of the world machine, set up for our sake by the best and most perfect Craftsman, was agreed upon by the philosophers, who otherwise have investigated with such meticulous care the minutest details of this world.

Thus, the sun is placed in the center of the universe. All this is suggested by the order in which the planets follow each other and by the harmony of the entire world, if only we look at it with both eyes, as the saying goes.

We are not to imagine that the heavens are made of crystal, or that the stars are fixed in solid spheres.

The Earth, together with its surrounding waters, is a sphere.

It is not necessary that the hypotheses be true, or even probable. It is enough that they provide a calculus which fits the observations.

For the universe, wrought for us by the best and most orderly Workman, is a machine divine, not human.

The sphere is the most perfect of all figures, and it is therefore fitting that the universe should be spherical.

I am aware that a philosopher's ideas are not measured by the common yardstick, for it is the duty of an astronomer to compose the history of the celestial motions from careful and expert study.

For it is not the business of the astronomer to know the true causes of the motions, but only to conceive and devise such hypotheses as, being assumed, the motions may be exactly calculated from them according to the laws of geometry, and arithmetic, for the time both past and future.

I have indeed been at great pains to learn the true motions of the heavenly bodies.

The Earth has three motions: a daily rotation, an annual revolution around the Sun, and a third motion of its axis.

The vastness of the heavens is so great that the Earth is but a point in comparison.

For it is manifest that the planets are not carried about by solid spheres, but move freely through the heavens.

The order of the planets is as follows: Saturn, Jupiter, Mars, Earth, Venus, Mercury, and the Sun in the center.

I am not unaware that the opinion of the Earth's motion is not new, but very old.

For it is the property of the human mind to be eager for new things.