Why does Galileo believe God approves of his discoveries? According to your Cartesians [followers of Descartes], everything is performed by an impulsion, of which we have very little notion; and according to Sir Isaac Newton, it is by an attraction, the cause of which is as much unknown to us. At Paris you imagine that the earth is shaped like a melon, or of an oblique figure; at London it has an oblate one. A Cartesian declares that light exists in the air; but a Newtonian asserts that it comes from the sun in six minutes and a half. . . . The very essence of things is totally changed. . . . How furiously contradictory are these opinions!