The purpose of the 37 volumes of his On Nature is to free us from the fear of death and therefore from the control of priests and from the internal fears of the religion that Plato and his followers had in mind. Epicurus says:
…[W]e must recognise generally that the soul is a corporeal thing, composed of fine particles, dispersed all over the frame….
…[T]he rest of the frame, whether the whole of it survives or only a part, no longer has sensation, when once those atoms have departed…. Moreover, once the whole frame is broken up, the soul is scattered and has no longer the same powers as before, nor the same notions; hence it does not possess sentience either.
The atoms that comprise the soul are immortal. They are passed on from being to being like the torch in one of the Athenian races. But the larger structure of atoms that is the soul of any one individual is itself mortal. Once we are dead, our atoms are recycled. Since there is nothing but atoms moving in the void, we as individuals are annihilated. After death, there is nothing; and because of that, death is nothing. Epicurus says:
Death is nothing to us; for that which has been dissolved into its elements experiences no sensations, and that which has no sensations is nothing to us.
After two thousand years of Christian spiritual hegemony, this may seem to many of us a gloomy doctrine. For Epicurus and his followers, however, it was a removal of the greatest barrier to happiness as they conceived it. That barrier was fear of endless punishment for the alleged sin of seeking their own happiness in life.
It may be, Lucretius says, that beating down religion is impious and the entry to a life of crime. Much rather, it is religion which has brought forth criminal and impious deeds. He lived before the most notable acts of religious mania. But he was poet enough to know the psychology of enthusiasm. In Book One of his poem, he produces one of the most striking of all denunciations of religion. He describes how, at the beginning of the Trojan War, the priests tell Agamemnon that a good passage across the Aegean required the sacrifice of his daughter. So a young girl was dragged to the altar for her throat to be cut by her own father.
He says later, in Book Three:
Some wear out their lives for the sake of a statue or a name. Religion and its resulting fear of death can induce one man to violate honour, another to break the bonds of friendship, and to overthrow all natural feeling. It has induced men to betray their country or their parents for the sake of avoiding hellfire. For just as children tremble and fear all in the darkness, so we in the light of day often fear what is no more real. This terror must be dispersed, not by rays of sunshine nor by the bright shafts of daylight, but by the sight and understanding of nature.
It is Epicurus, he says, who brought us into this light of understanding. Do not fear the priests. Do not fear death. Pay no attention to dreams or omens. These latter have a natural explanation. The former have neither a divine nature nor a prophetic power, but they are the result of images that impact on us.
Follow the ethical teachings of Epicurus, and be happy.
None of this means, by the way, that Epicurus and his followers were atheists. They did accept the existence of gods, and were willing outwardly to conform to whatever cults were established. They only denied that the gods were immaterial, and that the gods had any interest in human affairs. Confronted with evidence for any supernatural event, they were content with insisting on a natural cause, whether or not they were able to think of one that convinced.
Sean Gabb, “Epicurus: Father of the Enlightenment”, speaking to the 6/20 Club in London, 2007-09-06.