The dissertation is a reexamination of Epicurus's theory of the swerve (parenklisis; clinamen) of atoms and its place in his philosophical psychology.;The first three chapters cover several topics directly related to the swerve and its development. Chapter I discusses its authorship, and argues that although it is not mentioned in Epicurus's extant writings, there are compelling reasons to believe it is his. Chapter II examines the evidence for the nature of the swerve, discussing the way an atom swerves within the context of Epicurus's theory of minimal units of space, time, and motion. Chapter III treates the role of the swerve in Epicurus's physics, the relationship between the physical and psychological roles of the swerve, and the philosophical background of its development. I argue that the two roles of the swerve are closely connected, and that Epicurus was influenced in making the connection and in developing the swerve by Aristotle's discussion of cosmic motion, animal motion, and accidental self-motion in Physics VIII.;Chapter IV examines Lucretius 2.251-293, the main evidence for the place of the swerve in Epicurus's philosophical psychology. I argue that the two standard interpretations of the passage are incorrect. Lucretius does not say that the swerve is involved in free choice, nor that it frees us by disturbing the initial constitution of our souls. His main emphasis is on the swerve as an internal source of motion (initus motus) which allows him to distinguish at the atomic level between the forced and voluntary motions of all living creatues. Further discussion of precisely how the swerve does this is postponed until chapter VI.;Chapter V discusses Aristotle's treatment of the voluntary (to hekousion) and moral responsibility (to eph' hemin) in the EE, EN, and MA. I examine Aristotle's position that the voluntary actions of all living creatures involve an internal principle of motion (arche kineseos), and his identification of the principle as desire (orexis) and its physical basis, connate spirit (sumphuton pneuma). I also examine his treatment of moral responsibility, and conclude the chapter with a discussion of two topics, the change in the conception of causality and denial of an incorporeal soul, that altered the Hellenistic discussion of the voluntary and moral responsibility.;The Introduction outlines the problem of the swerve and the approach to be taken. I evaluate the two most influential modern interpretations, and argue they are unsatisfactory primarily because they fail to identify what the philosophical background of the swerve's development was and what the nature of the libera voluntas is that Lucretius says the swerve preserves. I distinguish among the voluntary (to hekousion), deliberate choice, and free choice, and claim that it is the first, voluntary action as performed by all living creatures, that Epicurus tried to explain with the swerve.;In the first part of chapter VI, I return to the Lucretius passage analyzed in chapter IV, and argue that Epicurus, attempting to account in atomic terms for the Aristotelian distinction between voluntary and forced actions, posited the swerve as the atomic equivalent of sumphuton pneuma. I suggest how the swerve, although occurring randomly, can be involved in apparently non-random actions. A second section shows how Epicurus, once he had developed the swerve, then applied it to answer a contemporary challenge to moral responsibility posed by the "Master Argument" of Diodorus Cronus. A final section treats evidence that Epicurus thought the swerve played an important role in the atomic explanation of thinking, perception, and memory. |