Case Study:  HOW COSMOLOGY BECAME A SCIENCE

The Book of the Cosmos. Imagining the Universe from Heraclitus to Hawking. 

Ch. 16. If a Man Were in the Sky and Could See the Earth Clearly, Nicole Oresme. “A medieval churchman, astronomer, and minister of finance considers the ‘economical’ idea that the earth rather than the rest of the universe rotates every twenty-four hours.”

• What does the term relativity mean, in the most general sense? How is it related to subjectivity and objectivity?

• Before putting his own arguments forward, Oresme presents the arguments of those with opposing views. Why does he do this? Wouldn’t this undermine his own arguments? Is it customary to this in science? Outside of science?

• Oresme argues for relativity of motion in the context of a moving ship. Why does he not just make abstract or philosophical arguments? Why use a ship as his example, rather than some other moving object?

• As part of his argument that the earth may as well be moving, Oresme asks the reader to imagine two hypothetical situations involving the motion of the earth and the heavens. How does relativity play a role in the argument?

• According to Oresme, “anybody with good sense” may easily imagine that they see the earth rotating below, from the vantage point of the sky. How might a common person be affected by this “experience?”

• Oresme again puts forward a ship as a model for the earth, to show that the air could move along with the earth, without causing great winds for those on its surface. How might this change a person’s conception of the earth as a whole? I.e., if the earth is like a ship, then what else might we conclude about the earth?

• If you shot an arrow straight up from a swiftly moving ship, would it come straight back down to the same spot? How do you know?

• Oresme refers to Aristotle as an authority several times, even though Aristotle had been dead for seventeen hundred years. Why was he still considered to be a legitimate source of knowledge, and a valid foundation for rational arguments? What did Aristotle do, that was so enduring?

• Does Oresme actually believe that the earth rotates, not the heavens? Does it matter?