In his version of atomism, Lucretius made explicit reference to the concept of an intrinsic declination of the atom, the atomic swerve (clinamen in Latin), stressing that the time and space of the infinitesimal atomic vibration is uncertain. The topic of this article is the Epicurean and Lucretian arguments in favour of the swerve. Our exposition of the Lucretian model of the atomic clinamen will present and elucidate the respective considerations on the alleged role of the swerve in the generation (...) of free-action. (shrink)