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!

what is the main idea of this passage?

sir isaac newton is the greatest scientist of this era.
light comes from the sun in fewer than seven minutes.
the followers of descartes know more than those who follow newton.
people still don’t understand how the world works.