“However, it is not the case that in any genus—even [the genus] of motion—we come to an unqualifiedly maximum and minimum. Hence, if we consider the various movements of the spheres, [we will see that] it is not possible for the world-machine to have, as a fixed and immovable centre, either our perceptible earth or air or fire or any other thing.
“Hence, the world does not have a [fixed] circumference. For if it had a fixed center, it would also have a [fixed] circumference; and hence it would have its own beginning and end within itself, and it would be bounded in relation to something else, and beyond the world there would be something else and space (locus). But all these [consequences] are false. Therefore, since it is not possible for the world to be enclosed between [a physical] center and a physical circumference, the world—of which God is the centre and the circumference—is not understood. And although the world is not infinite, it cannot be conceived as finite, because it lacks boundaries within which it is enclosed” (Nicholas of Cusa, On Learned Ignorance, trans. Jasper Hopkins [Minneapolis: Banning, 1981], II.11; p. 114).
Karsten Harries associates this quotation with the Camille Flammarion woodcut (pictured above) in her Infinity and Perspective (pp. 46-8). The caption on the woodcut reads Un missionaire du moyen age raconte qu’il avait trouvé le “point où le ciel et la Terre se touchent”. Nothing more to add just now, but I really dig this.