For a symbol is like a rock dropped into a pool: it sends out ripples in all directions, and the ripples are in motion. Who can say where the last ripple disappears? One may have a sense that he at least knows approximately the center point of all those ripples, the point at which the stone struck the water. Yet even then he has trouble marking it precisely. How does one make a mark on water? ... The ripples continue to move and the light to change on the water and the longer one watches the more changes he sees. And such shifting-and-being-at-the-same-instant is of the very sparkle and life of poetry. Of poetry and of life itself. For the poem is a dynamic and living thing. One experiences it as one experiences life—as everybody but Mr. Gradgrind experiences life. One is never done with it: every time he looks he sees something new, and it changes even as he watches. And that very sense of continuity in fluidity is one of the kinds of knowledge, one of the ways of knowing, that only the arts can teach, poetry foremost among them.