Astronomy Is Written For Astronomers

We Regard It As A Certainty That The Earth, Enclosed Between Poles, Is Bounded By A Spherical Surface.

Those Things Which I Am Saying Now May Be Obscure, Yet They Will Be Made Clearer In Their Proper Place.

So Far As Hypotheses Are Concerned, Let No One Expect Anything Certain From Astronomy, Which Cannot Furnish It, Lest He Accept As The Truth Ideas Conceived For Another Purpose, And Depart From This Study A Greater Fool Than When He Entered It.

For When A Ship Is Floating Calmly Along, The Sailors See Its Motion Mirrored In Everything Outside, While On The Other Hand They Suppose That They Are Stationary, Together With Everything On Board. In The Same Way, The Motion Of The Earth Can Unquestionably Produce The Impression That The Entire Universe Is Rotating.

Those Who Know That The Consensus Of Many Centuries Has Sanctioned The Conception That The Earth Remains At Rest In The Middle Of The Heavens As Its Center, Would, I Reflected, Regard It As An Insane Pronouncement If I Made The Opposite Assertion That The Earth Moves.