Physically considered, the Earth is a globe; all the authors of the high Middle Ages are agreed on this. In the earlier 'Dark' Ages, as indeed in the nineteenth century, we can find Flat-earthers. Lecky, whose purpose demanded some denigration of the past, has gleefully dug out of the sixth century Cosmas Indicopleustes who believed the Earth to be a flat parallelogram. But on Lecky's own showing Cosmas wrote partly to refute, in the supposed interests of religion, a prevalent, contrary view which believed in the Antipodes. Isidore gives Earth the shape of a wheel (xrv, ii, I). And Snorre Sturlason thinks of it as the 'world-disc' or heimskringla-the first word, and hence the title, of his great saga. But Snorre writes from within the Norse enclave which was almost a separate culture, rich in native genius but half cut off from the Mediterranean legacy which the rest of Europe enjoyed.
The implications of a spherical Earth were fully grasped. What we call gravitation - for the medievals 'kindly enclyning' - was a matter of common knowledge. Vincent of Beauvais expounds it by asking what would happen if there were a hole bored through the globe of Earth so that there was a free passage from the one sky to the other, and someone dropped a stone down it. He answers that it would come to rest at the centre. Temperature and momentum, I understand, would lead to a different result in fact, but Vincent is clearly right in principle. Mandeville in his Voiage and Travaile teaches the same truth more ingenuously: 'from what part of the earth that men dwell, either above or beneath, it seemeth always to them that dwell that they go more right than any other folk. And right as it seemeth to us that they be under us, right so it seemeth to them that we be under them' (xx). The most vivid presentation is by Dante, in a passage which shows that intense realising power which in the medieval imagination oddly co-exists with its feebleness in matters of scale. In IL Ferno, the two travellers find the shaggy and gigantic Lucifer at the absolute centre of the Earth, embedded up to his waist in ice. The only way they can continue their journey is by climbing down his sides - there is plenty of hair to hold on by - and squeezing through the hole in the ice and so coming to his feet. But they find that though it is down to his waist, it is up to his feet. As Virgil tells Dante, they have passed the point towards which all heavy objects move. It is the first 'science-fiction effect' in literature.
The erroneous notion that the medievals were Flatearthers was common enough till recently. It might have two sources. One is that medieval maps, such as the great thirteenth-century mappemounde in Hereford cathedral, represent the Earth as a circle, which is what men would do if they believed it to be a disc. But what would men do if; knowing it was a globe and wishing to represent it in two dimensions, they had not yet mastered the late and difficult art of projection? Fortunately we need not answer this question. There is no reason to suppose that the mappemounde represents the whole surface of the Earth. The theory of the Four Zonesr taught that the equatorial region was too hot for life. The other hemisphere of the Earth was to us wholly inaccessible. You could write science-fiction about it, but not geography. There could be no question of including it in a map. The mappemounde depicts the hemisphere we live in. The second reason for the error might be that we find in medieval literature references to the world's end. Often these are as vague as similar references in our owntime. But they may be more precise, as when,in a geographical passage, Gower says
Fro that into the worldes ende
Estward, Asie it is. (pp, 141-142)
I have made no serious effort to hide the fact that the old Model delights me as I believe it delighted our ancestors. Few constructions of the imagination seem to me to have combined splendour, sobriety, and coherence in the same degree. It is possible that some readers have long been itching to remind me that it had a serious defect; it was not true.
I agree. It was not true. But I would like to end by saying that this charge can no longer have exactly the same sort of weight for us that it would have had in the nineteenth century. We then claimed, as we still claim, to know much more about the real universe than the medievals did; and hoped, as we still hope, to discover yet more truths about it in the fu ture. But the meaning of the words 'know' and 'truth ' in this context has begun to undergo a certain change.