eory of Epicurus, were thus inseparable.
A man could not be happy until he had surmounted the fear of death and
the fear of gods instilled by the current fables, which disturbed all
tranquillity of mind; until he had banished those factitious desires
that pushed him into contention for wealth, power, or celebrity; nor
unless he behaved with justice to all, and with active devoted
friendship towards a few. Such a mental condition, which he thought it
was in every man's power to acquire by appropriate teaching and
companionship, constituted virtue; and was the sure as well as the only
precursor of genuine happiness. A mind thus undisturbed and purified
was sufficient to itself. The mere satisfaction of the wants of life,
and the conversation of friends, became then felt pleasures; if more
could be had without preponderant mischief, so much the better; but
Nature, disburthened of her corruptions and prejudices, required no
more to be happy. This at least was as much as the conditions of
humanity admitted: a tranquil, undisturbed, innocuous, non-competitive
fruition, which approached most nearly to the perfect happiness of the
Gods.[17]

The Epicurean theory of virtue is the type of all those that make an
enlightened self-interest the basis of right and wrong. The four
cardinal virtues were explained from the Epicurean point of view.
_Prudence_ was the supreme rule of conduct. It was a calculation and
balancing of pleasures and pains. Its object was a judicious selection
of pleasures to be sought. It teaches men to forego idle wishes, and to
despise idle fears. _Temperance_ is the management of sensual
pleasures. It seeks to avoid excess, so as on the whole to extract as
much pleasure as our bodily organs are capable of affording.
_Fortitude_ is a virtue, because it overcomes fear and pain. It
consists in facing danger or enduring pain, to avoid greater possible
evils. _Justice_ is of artificial origin. It consists in a tacit
agreement among mankind to abstain from injuring one another. The
security that every man has in his person and property, is the great
consideration urging to abstinence from injuring others. But is it not
possible to commit injustice with safety? The answer was, 'Injustice is
not an evil in itself, but becomes so from the fear that haunts the
injurer of not being able to escape the appointed avengers of such
acts.'

The Physics of Epicurus were borrowed in the main from the atomic
theory of Democri