4. The Threshold In Nature and In Man

Now, this heliocentric picture of the world already existed in earlier ages. Plutarch is a writer from whom we can learn a great deal concerning the men of olden times, and how they thought about the world. Let me read you a passage translated from his writings. Plutarch is speaking of Aristarchus of Samos, and he describes the way in which Aristarchus conceived the world. We are therefore taken back into early Greek times, into an epoch many centuries before the Middle Ages, and before Copernicus. In the opinion of Aristarchus, says Plutarch, the universe is much bigger than it looks; for Aristarchus makes the assumption that the stars and the sun do not move, but that the earth revolves round the sun as centre, while the sphere of the fixed stars, whose centre is also in the sun, is so immense that the circumference of the circle described by the earth is to the distance of the fixed stars as is the centre of a sphere to its entire surface.