Abstract

In lieu of an abstract, here is a brief excerpt of the content:On Dante, Hyperspheres, and the Curvature of the Medieval CosmosWilliam EggintonIn the course of his lectures on medieval literature at Oxford University in the 1950s C. S. Lewis would ask students to walk alone at night, gaze at the star-filled sky, and try to imagine how it might look to a walker in the Middle Ages. It would not likely have occurred to him that some forty years later several astrophysicists would ask that their readers perform the same activity, at least figuratively—not, however, with the intention of experiencing medieval conceptions of the cosmos but rather in order to begin to imagine the shape of our own. One of the astrophysicists in question is Stanford Professor Emeritus Robert Osserman, whose 1995 book The Poetry of the Universe is an attempt to acquaint lay readers with what the most recent research suggests is the shape of the universe by leading them through a brief history of the mathematical and technological developments that made such boundary-breaking thought possible. Paradoxically, when it comes to trying to imagine that all-encompassing form which is derived from a four-dimensional mathematical model called a hypersphere, he turns not to ultra-modern computer-generated images nor to dry but technically accurate exegeses of mathematical formulae but rather to the verses of a fourteenth-century Italian poet, Dante Alighieri. His claim is that in the third canticle of the Divine Comedy, which details his ascent through the heavens, Dante describes the cosmos with astonishing precision as a hypersphere, exactly as modern physics has determined it to be.If the cosmology of the present makes use of Dante heuristically, however, it never asks the most obvious question: Why? Why does one need to go back to the fourteenth century for a poetic description of how the universe appears to modern science? Osserman assumes it to be a mere coincidence, and why should he not? What possible access would a thinker—a poet even—of the European Middle Ages have to the highest achievements of almost six centuries of subsequent thought? In answering this question, I am not proposing to naively interpret the past in our own image, claiming Dante to be a mathematical genius [End Page 195] before his time. I am, however, suggesting that there is an excellent explanation for why one must look to the fourteenth century for models of expression adequate to the challenges posed by nineteenth and twentieth-century advances in mathematics: namely, that in the course of the Scientific Revolution, wherein were laid the epistemological foundations for the discoveries of modern science, certain possibilities of thought and imagination were discarded, forgotten, and certain abilities were, if only temporarily, lost. The Middle Ages has long been painted as a period whose culture was hostile to free thought and new knowledge; perhaps it is now time to recognize that it was also a time in which phenomena could sustain mutually exclusive and contradictory explanations, when the battle between faith and science had not yet been conclusively won by either side, and when the efforts to bridge the stories they told could produce conceptual edifices whose mere possibility would be unthinkable only 200 years later. This essay is about one such conceptual edifice and how openness to its perspective allowed a poet to put into words what could not be imagined by his descendants, and what eludes us even today.The Shape of the Modern UniverseImagine that you are a completely flat creature, living happily in your two-dimensional world.1 As observers we are outside this world, and we can see you milling about with your flat friends, blissfully unaware of the uncharted regions one dimension away on either side of you. Now imagine that this plane is not flat—in the sense of rectilineal—as you might have created it in your mind, but rather is curved; in fact it is a sphere. Assuming that this sphere is large enough, there is no reason that you, an inhabitant of this surface, should be aware of its curvature. Even we, the three-dimensional observers, if close enough to the surface, would not recognize its curvature. One could conjecture, however...