"In January 1821, Thomas Jefferson wrote John Adams to "encourage a hope that the human mind will some day get back to the freedom it enjoyed 2000 years ago." This wish for a return to the era of philosophy would put Jefferson in the same period as Titus Lucretius Carus, thanks to whose six-volume poem De Rerum Naturum (On the Nature of Things) we have a distillation of the work of the first true materialists: Leucippus, Democritus, and Epicurus. These men concluded that the world was composed of atoms in perpetual motion, and Epicurus, in particular, went on to argue that the gods, if they existed, played no part in human affairs. It followed that events like thunderstorms were natural and not supernatural, that ceremonies of worship and propitiation were a waste of time, and that there was nothing to be feared in death."