Metaphysical and ethical doctrines taught by Epicurus .
In metaphysics, the basic concepts of Epicureanism were atomism ; mechanical causality limited by the spontaneous "swerve" of atoms, which accounted for the freedom of motion in man and animals; the infinity of the universe; and the existence of gods as beatified and immortal natures completely extraneous to happenings in the world. In ethics, the basic concepts were the identification of the good with pleasure and of the supreme good with the absence of bodily and mental pain; the limitation of all desire and the practice of virtue; withdrawal from public life; and the cultivation of friendship. Because of its dogmatic character and its practical end, Epicureanism did not lend itself easily to development.