The fact of rising without apparent motive force through a medium lighter than his own body, at once forms a subject for enquiry on Dante’s part; and Beatrice, as she has frequently to do in the course of their journey, resolves his doubt. Those who are reading the poem for the first time will probably pass lightly over these difficult metaphysical passages. They must be read sooner or later by any one who wishes thoroughly to understand Dante’s place in the history of speculative thought; but in the first instance it will probably be better to “take them as read” and endeavour to get a clear notion of the general arrangement. There are obvious reasons why this portion of the poem should consist as largely as it does of these subtle disquisitions. There is far less room, in the first place, for variety of description. In a region where there are no shadows, it is impossible to give a detailed picture; and terms indicative of simple brightness are limited. Nor, again, is it easy where all are perfect to depict individual character. Consequently two great elements of interest in the first two parts of the poem are far less available here; and their place must be filled by other matter. What this matter should be is suggested by the natural division of speculative science into Ethics, or the study of man’s conduct as a moral being; Politics, or the science relating to his behaviour in regard to the social order; and Metaphysics, which for Dante is synonymous with theology, the investigation of all that concerns his spiritual part, as well as the Divine order generally. With the first two we have dealt in the _Hell_ and the _Purgatory_ respectively; the third is reserved for the _Paradise_. Once or twice indeed Dante touches on matters that would seem more fitly to belong to the others; as, for instance, the magnificent passage in Canto vi., where Justinian, after sketching the triumphant course of the Roman Eagle, inveighs against the party feuds of the time; or Carlo Martello’s reference to the Sicilian Vespers, and the misdeeds of his brother Robert. But of these the first leads up to an elaborate exposition of the scheme of Redemption, the second seems intended directly to introduce a dissertation on matters lying at the very root of human nature. To the same difficulty in varying the methods (to use a phrase of Ginguéné’s) must be attributed the occurrence of a good many conceptions which to our taste appear somewhat grotesque. Yet the better we know the poem the more we shall feel that in this third part the author’s genius rises to its sublimest efforts, and agree with the late Dean of St. Paul’s, that it is the true _pierre de touche_ of the student of Dante.