Epicurus (ca. 342-270 B.C.) was a Greek philosopher and the founder of Epicureanism. He was the first of the overt therapy philosophers and an upholder of the atomic theory.
Epicurus was born either in Samos or in Athens. He spent his youth in the Athenian colony of Samos, and at the age of 18 he made his way to Athens. In the upheaval resulting from the death of Alexander the Great (323 B.C.), the Athenian colonists, including Epicurus's father, Neocles, were driven out of Samos. Epicurus rejoined his father in Colophon and spent the next several years in Colophon, Lampsacus, and Mytilene, gathering disciples to his own emerging philosophical doctrines
About 307/306 Epicurus returned to Athens, and at first, according to Diogenes Laertius, seems to have spent some time with other professional philosophers in the pursuit of philosophy. Soon, however, he founded his own school, which has since borne his name. Epicurus was subject, even in his own lifetime, to opprobrious comment; among other things he was accused of gluttony, womanizing, and unwarranted contempt for other philosophers, antecedent and contemporary. Given the strength of his own convictions, the latter accusation may have had substance; all evidence we have suggests that Epicurus spoke his mind. The other accusations appear to be groundless. He was physically infirm and lived a life of abstemiousness, if not of complete asceticism. He was characterized by his love for his parents, his generosity to his brothers, and his gentleness toward his slaves. He was also respectful to the gods, no doubt on the grounds that they were the example of that freedom from physical pain and mental tranquility that he saw as the supreme human goal.
Epicurus's output was very large; Diogenes Laertius, his principal biographer, lists 40 works, one of them, On Nature, comprising 37 books. All that has survived is what seems to be an abridged version of Epicurus's philosophy in the form of three letters, a few fragments, and a collection of his more important sayings entitled Major Opinions. The latter, however, is likely a compendium put together by disciples, as is undoubtedly the case with the Senteniae Vaticanae, discovered in the 19th century. The Letter to Herodotus deals with Epicurus's physics and his theory of knowledge and perception. The Letter to Pythocles deals with his far less confident opinions on astronomy and meteorology. And the Letter to Menoeceus treats his theory of conduct.
All that exists, Epicurus says, consists of matter, void, and their accidents, or properties. The universe is infinite in time and space and contains an infinite number of eternally moving indestructible elements called "atoms." The number of types of atom is, he says, "inconceivably large," and there is an infinite number of each type. The atoms are not further splittable, though they are logically divisible into "minimal parts," which serve as integral units of measurement in the distinguishing of different sizes of atoms. The atoms are like sense objects in possessing mass, size, and shape.
"Creation from nothing" and "substantial" change are meaningless terms. Any change in the universe is reducible to alteration of position. Atoms are invisible, by definition; and their motions, be it in the "free fall" of the void, or from mutual collision, or in the "vibration" within a compound body, are of equal velocity, which he equates with the "speed of thought." In this respect size, mass, and other factors are irrelevant. In the matter of speed the only difference between atoms is that, thanks to the deflections consequent upon collisions, the net distance covered by one atom will differ from that covered by another.
In the infinite universe there is an infinite number of earth systems similar to our own, constantly waxing and waning. These earth systems are of various shapes, but in each instance the "earth" is a plane, like our own. "Up" and "down" are apparently meaningful terms to Epicurus, even in an infinite universe; what is "up" for our earth system is "down" for the one immediately "above" us. The universe is an infinity of space "up" and an infinity of space "down."
The question of the first collision of atoms is not discussed in the extant works of Epicurus. The problem is an acute one, since atoms falling eternally "down" at uniform speed will never meet, and the organized world described by Epicurus becomes an impossibility. It seems clear from other ancient sources that Epicurus did in fact postulate a "swerve" of one or more atoms as the initial or eternally recurring source of the collisions that are so crucial to his physical theory.
Whether Epicurus also postulated the existence of such a swerve of one or more soul atoms, early on in life, to account for man's free will is a matter for current conjecture. What we are sure of is that, by apparent contrast with Democritus, Epicurus was an atomist who was also profoundly antideterminist.
The criteria for judging questions of truth content and moral worth are primitive sensations, primitive feelings, and "concepts" (which ultimately reduce to the first two). A life lived in accord with these will achieve the maximal human good—freedom from bodily pain and freedom from mental anxiety. In the matter of sense perception, truth is attained by direct contact with the shape and qualities of an object, either by physical contact or by apprehension of the "idols" incessantly streaming off all physical subjects and, at least for a time, retaining their form and color.
Error lies in the hasty interposition of opinion into this scheme of things, without waiting for the corroboration of further sense evidence. Concepts, being constructs of sense data and feelings, are meaningful and helpful as criteria to the degree that they stem directly from sense data and feelings, without the interposition of hasty opinion. Among such concepts are the two crucial ones of atoms and void, the existence of neither of which is amenable to empirical demonstration.
A crucial exception to all this is constituted by the "idols" of the gods. These penetrate the mind directly to form our concepts, without previously impinging upon the sense organs or influencing our feelings. Our certitude of the gods' existence stems from the clarity of our mental perception of the fact; men's view of their nature, however, says Epicurus, is usually ridiculous—thanks again to the interposition of groundless opinion into the matter. The gods live eternal lives of contentment in the void of the universe and have no concern with men. There are no rewards or punishments after death; death is extinction. Dying might reasonably—though mistakenly, he feels— seem a cause for fear; to fear death itself, however, is absurd, since it brings nothing in its wake.
This cardinal tenet about the nature of the gods and death is bound up with Epicurus's views on the soul. In spite of his physical theory, he is still (perhaps surprisingly) a dualist in matters concerning the mind and the body. Soul or mind, however, he sees as completely material; it is composed of very small, fine, round atoms. It gives sensation to the body and in turn needs the receptacle of the body to exercise its function of sensing. The body, at the same time, is given a degree of sensation by the soul. But neither soul nor body can sense apart; hence the fact that their dissolution at death is immediate annihilation for the whole person.
Epicurus therefore suggests that the end of human life should be pleasure—defining it as freedom from physical and mental pain. The positive delights that other men call "pleasure" are merely variations on the true, basic, contentment man needs and can easily achieve; they in no sense increase his happiness. A good life is guided by practical wisdom, a sense of responsibility for our decision making, self-sufficiency, and the careful application of the hedonistic calculus. This necessarily involves freedom from all fear and knowledge of the limits of our desires. Once we see that only "necessary" and nonharmful desires need be assuaged, we have removed a major obstacle to the achieving of the plenitude of human contentment.
Epicurus advocated (and practiced) a life of withdrawal from politics. The highest human communion was for him the company of friends. The degree of happiness these gave him is eloquently attested to in a last letter to Idomeneus: "On this truly happy day of my life, as I am at the point of death, I write this to you. The disease in my bladder and stomach are pursuing their course, lacking nothing of their natural severity; but against all this is the joy in my heart at the recollection of my conversations with you."
For a fully annotated edition of Epicurus's extant works consult Epicurus: The Extant Remains, edited and translated by Cyril Bailey (1926). This book, while open to criticism on some matters of detail, is still the most reliable edition in English. Bailey's more discursive study, The Greek Atomists and Epicurus (1928), is also recommended. A book notable for the quality of its scholarship and the depth of its sympathy with Epicurus is A.-J. Festugière, Epicurus and His Gods, translated by C. W. Chilton (1955). For a sophisticated study of two basic problems in Epicurus see David J. Furley, Two Studies in the Greek Atomists (1967). Norman Wentworth De Witt, Epicurus and His Philosophy (1954), and Benjamin Farrington, The Faith of Epicurus (1967), should both be used with caution. See also George A. Panichas, Epicurus (1967).