What is needed is a readiness to undervalue the world altogether. This is only possible for a Christian. Willingness to laugh at the pompous hyperboles and banalities of moon-shots may need to be cultivated by some. The "scientific mind" is far too specialized to grasp very large jokes. For example, Newton did not discover gravity, but levity, not earth-pull, but moon-pull. To this day no scientist has a single clue as to what "gravity" is. In the eighteenth century it was defined as: "a mysterious carriage of the body to conceal the defects of the mind." The comedy of science as presented by Swift in the third book of Gulliver 's Travels (Leputa, the floating island) employed the principle of levity to enlarge the gaiety of nations.