Time's arrow of “just history†marks each moment of time with a distinctive brand. But we cannot, in our quest to understand history, be satisfied only with a mark to recognize each moment and a guide to order events in temporal sequence. Uniqueness is the essence of history, but we also crave some underlying generality, some principles of order transcending the distinction of moments—lest we be driven mad by Borges's vision of a new picture every two thousand pages in a book without end. We also need, in short, the immanence of time's cycle.
Stephen Jay Gould