Mental conflict is the condition of a divided mind consciously torn between contrary desires or beliefs. For Greek philosophers it is a puzzle provocative of theory; they accommodate it differently with different structurings of the mind's operations. Socrates focuses all a man's desires upon a single goal taken to constitute the human good. This permits vacillation between varying conceptions of the end or devisings of the means, and consequent regret; but judgement, or misjudgement, is always in control. Plato comes instead to find a disunity in desire, which means that reason may fail to be master within its own house. Unity is to be worked for in the convergence of all desires through the persuasions of reason. Aristotle assents to rather the same view, but supposes that, when reason fails to win out in action, it also loses out in judgement, ceasing to perceive the demands of the situation. Plato's practical reason is a child of heaven, whose voice is not stilled by being unheeded, while Aristotle's is a creature of earth, emergent out of desire and eclipsed by desires in effective revolt. The Stoics return to a Socratic insistence that the decision of my reason is my decision, but they are unable to maintain that the person remains single as the subject of decision, the agent of action and the bearer of responsibility. This book is the first detailed analysis of the treatment of Mental Conflict by the Greek philosophers. It will be important reading for all students and teachers of ancient and moral philosophy.