was born on the Greek island of Samos. He studied philosophy from an early age and from 310 taught in Mytiline
and later in Lampsachus. In 306 he
bought a garden in Athens, where he established his famous school and remained
for the rest of his life engaged in philosophical discussion and research. He was a prolific writer, but only a few
works have survived; and most of what we know of his philosophy we owe to On the Things of Nature by the Roman
his 'Canonic' (theory of knowledge) Epicurus said that external bodies, that is, collections of atoms,
produce images (eidola) which pass into our sense organs (and thereby
the 'soul atoms') to produce (1) clear representations or 'perceptions' (phantasiai)
corresponding to those bodies. (What we today term 'secondary'
qualities belong in reality to these composite perceptions, whereas 'primary'
qualities such as shape and size are properties of atoms.); (2)
complexes of images which do not correspond (as in illusions); and (3) memory
images and 'preconceptions'
(prolepseis), that is, general
concepts which underlie our use of language and help us to discriminate between
our sense-experiences. Sense-perception and hence
concepts thus provide two criteria for the truth of our opinions. Knowledge is thereby grounded in the indisputability
of immediate experience [a]. Empirical inspection enables us to verify whether
our experiences do or do not correspond to external objects existing now or in
the future; while in the case of unobservables, such as atoms, the test is that
opinion must not conflict with experience. The feelings of
pleasure or pain which accompany sense-experience constitute a third criterion
and form the basis of our knowledge of what is good or bad [b]. (Epicurus generally accorded little
importance to mathematics and science as such.)
PHILOSOPHY OF NATURE
 Epicurus says that the universe is made up of two ultimate and real
entities: extended but not infinitely
divisible atoms and the void [a] in which they are located. These atoms, which
vary in size, shape, and weight, are in constant motion. He accounts for the origin of the world by his notion of a spontaneous
or chance 'swerve' which resulted in collisions and rotary movements,
and a multiplicity of worlds separated by empty spaces (metacosmia). In this way he supposed some degree of human
freedom to have been preserved [b]. Even the
gods, who live and enjoy themselves in the metacosmia,
are made of atoms though of the finest kind, but they have no creative
powers. The world can therefore be explained entirely in terms of
mechanical causes [c].
 Like his body, man's soul, which may be understood as the
principle of life if not with life itself, is made of material atoms [a] but they are round and smooth. The soul consists of an irrational part diffused throughout the body,
and a rational soul [b] (or 'conscious reason') in his breast as shown by
his emotions. Epicurus rejects the idea of the soul's
immortality [c]; at death the atoms
separate and perception ceases.
 The end
of life is pleasure. But by this Epicurus does not mean instant
sensual gratification but a long-term
absence of pain. This is to be found in
tranquillity (ataraxia) or serenity
of the soul and hence 'happiness' [a]. He is thinking here particularly of intellectual pleasures
which can help us to endure the sufferings of the body. To
realize this state a man must follow the path of virtue: he must be just, moderate, temperate,
cheerful the value of such qualities being judged by Epicurus solely
in terms of the extent to which they enable the individual to achieve his
end. But before acting he must choose
intelligently. This requires practical wisdom, the highest
virtue, which consists in the practice of 'right measure' (symmetresis) [b], the
balancing of happiness against unhappiness. The closer men get to tranquillity the more at ease they find themselves
with the world; and they can then enjoy the friendship of others without fear
of distraction. Indeed Epicurus regards
friendship as the most important means of achieving contentment.
Rejecting both scepticism
and Platonic idealism Epicurus looked for a secure foundation for his
thought. However, despite his adoption
of a physics derived from the Atomists and his commitment to an essentially
empiricist view of knowledge, his theoretical philosophy was generally
subordinated to his ethics his quest being not for ephemeral sensual pleasure
but for the intellectual and spiritual pleasures of the virtuous man which lead
to serenity of the soul. "The wise man
is happy even when being tortured on the rack." Clearly such a philosophy runs the risk of encouraging self-centredness: but it would seem that for Epicurus, while
the cultivation of friendships and active participation in society might be
motivated by considerations of one's own moral well-being, altruistic
tendencies may well arise naturally in the context of one's relationships with
others. Nevertheless the Epicurean
philosopher must be to some extent calculating so as to know what balance
should be struck in his day-to-day activities if the end of tranquil pleasure
is to be realized.
[Epicurus:] Lucretius, De rerum naturae (On the Things of Nature) there are
Penguin and Loeb Classical Library editions; Long and Sedley, op. cit., chs 4-25.
J. C. A. Gaskin, The Epicurean Philosophers.
J. M. Rist, Epicurus: An Introduction.