Epicureanism is a system of philosophy based upon the teachings of the ancient Greek philosopher Epicurus, founded around 307 BC. Epicurus was an atomic materialist, following in the steps of Democritus. His materialism led him to a general attack on superstition and divine intervention. Following Aristippus—about whom very little is known—Epicurus believed that what he called "pleasure" is the greatest good, but the way to attain such pleasure is to live modestly and to gain knowledge of the workings of the world and the limits of one's desires. This led one to attain a state of tranquility (ataraxia) and freedom from fear, as well as absence of bodily pain (aponia). The combination of these two states is supposed to constitute happiness in its highest form. Although Epicureanism is a form of hedonism, insofar as it declares pleasure to be the sole intrinsic good, its conception of absence of pain as the greatest pleasure and its advocacy of a simple life makes it different from "hedonism" as it is commonly understood.