" Fourth, they sometimes ‘swerved’. The swerve was a deviation from the basic downward path. It occurred frequently enough to cause the entanglement of many atoms; the result was a universe containing objects of a sufficient size to be experienced instead of a universe in which individual imperceptible atoms simply rained down. The atomic swerve, Epicurus thought, could supply the basis for free will, if only by providing a model of spontaneous, unpredictable, undetermined action. "

― Catherine Wilson , Epicureanism: A Very Short Introduction