As for Paolo and Francesca, Ugolino, and a hundred other passages, with those single lines that enrich memory,[16] no better praise can be compassed than Matthew Arnold’s word “touchstones.” They tell us, better than any definition, what poetry is. But the mere historical significance of Dante’s luminous precision is its vindication of that true theory of poetic diction which was formulated in the _De sublimitate_.[17] The essential character of poetic style is not dilation, which belongs to rhetoric; it is sublimation. Dante’s extraordinary conciseness, austere, ascetic, is never bare; it is surcharged. For style too, as well as for composition, he must have discerned that ancient critic’s fine distinction: rhetoric and poetic must never be confused; but at high temperatures they can be welded together. Poetry conveyed vision oftener, perhaps, in the middle age than in any other period. _Piers Plowman_ and _Pearl_ carry on in the next century a persistent medieval preoccupation. The _Divina Commedia_, fulfilling this aspiration, reveals man’s need, his quest, his attainment, of vision. “Blessed are the pure in heart; for they shall see God.” Purity remains negative to those who have no desire to see God. But Dante answers those for whom it is positive and constructive. Ye other few, who have lifted up your necks betimes to the bread of angels, by which men live here, but with which none cometh away sated. III. ii. 10. The poetry of this “concreate and perpetual thirst” (III. ii. 19) animates for all time a whole cosmogony antiquated merely as science, and communicates the great philosophy of the middle age to the heart. The _Divina Commedia_ achieved the high quest of the Grail romances. It is _the_ vision poem. The heaven of Dante’s vision transcends time and space. And I was with him; but of my mounting I was no more aware than is a man, ere his first thought, aware that it is coming. Beatrice is she who thus discloses from good to better so instantly that her act has no extent in time. III. x. 34. Brother, thy high desire shall be fulfilled in the last sphere, where all the rest are fulfilled, and mine.... For it is not in space, nor hath it poles, and our ladder attains even so far. III. xxii. 61. But it is not reserved for rapt contemplatives. Of the seraphim he who is most rapt, Moses, Samuel, or that John whom thou choosest to take, nay, even Mary has not a seat in another heaven than these spirits who but now appeared to thee; nor have they to their being more or fewer years; but all make beauteous the first circle, and have sweet life differently as they feel more or less the eternal breath. III. iv. 28.