When Heraclitus said that everything passes steadily along, he was not inciting us to make the best of the moment, an idea unseemly to his placid mind, but to pay attention to the pace of things. Each has its own rhythm: the nap of a dog, the procession of the equinoxes, the dances of Lydia, the majestically slow beat of the drums at Dodona, the swift runners at Olympia.