Dialectic in Ancient Greek and Roman Philosophy

What is dialectic? The question has no simple answer: different philosophers and philosophical schools in the ancient world use the expression “dialectic” (or rather the Greek “dialektikē”) in a number of importantly different ways. But there is at least some family resemblance between the various methods, disciplines, activities, and forms of argument that bear the name. The word is cognate with the ordinary Greek verb “dialegesthai,” which can mean “to have a conversation,” “to discuss,” or “to argue” (inter alia). Accordingly, the earliest uses of “dialectic” refer to practices that involve discussing some topic by means of questions and answers; later uses typically retain some connection to the idea of a dialogue, although this connection is sometimes tenuous. Some of the principal accounts covered in this article are as follows: first, Plato uses the expression “dialectic” (which he may have coined) for various methods of philosophical inquiry into principles, forms, or definitions. These methods range from Socrates’ practice of conducting a conversation by asking a series of questions that gradually uncover inconsistencies in his interlocutor’s beliefs, to more abstract procedures of somehow grasping fundamental, explanatory principles and deriving further truths from them. Second, Aristotle regards dialectic as the skill of being able to discuss any question whatever on the basis of common-sense or widely accepted opinions. Its role in philosophical inquiry is less central for him than for Plato, but some scholars think that he still takes it to have an important part to play in investigations into fundamental principles. Third, a group of philosophers associated with Diodorus Cronus may have belonged to a so-called “Dialectical School.” These philosophers have a great deal of interest in logical paradoxes and develop influential views on the truth conditions of conditionals and on modality. Fourth, Stoic philosophers class dialectic as a part of logic, one of the three main branches of philosophy. Various accounts are recorded: according to one, it is the skill of being able to conduct oneself well in question-and-answer discussion; according to another, it is “the science of what is true, what is false, and what is neither” (DL 7.62). Finally, some skeptical philosophers of the Hellenistic period engage in practices that have often been called dialectical. Arcesilaus and Carneades, two leaders of Plato’s Academy during its skeptical phase, were known for their ability to argue on both sides of any given question, with the aim of inducing suspension of judgement.