John Archibald Wheeler Quote
Of all obstacles to a thoroughly penetrating account of existence, none looms up more dismayingly than time. Explain time? Not without explaining existence. Explain existence? Not without explaining time. To uncover the deep and hidden connection between time and existence, to close on itself our quartet of questions, is a task for the future.
From "Hermann Weyl and the Unity of Knowledge", American Scientist, Vol. 74, July-August 1986, pp. 366-375. Reprinted in At Home in the Universe (1993), p. 171.