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The term dialectic originates in the Greek expression for the art of conversation (διαλεκτικ τέχνη ). So far as its great variety of meanings have anything in common, it is perhaps that dialectic is a method of seeking and sometimes arriving at the truth by reasoning, but even this general description, which to fit the variety of cases is so vague as to be valueless, fails to do justice to the Hegelian and Marxist notion of dialectic as a historical process. However, among the more important meanings of the term have been (1) the method of refutation by examining logical consequences, (2) sophistical reasoning, (3) the method of division or repeated logical analysis of genera into species, (4) an investigation of the supremely general abstract notions by some process of reasoning leading up to them from particular cases or hypotheses, (5) logical reasoning or debate using premises that are merely probable or generally accepted, (6) formal logic, (7) the criticism of the logic of illusion, showing the contradictions into which reason falls in trying to go beyond experience to deal with transcendental objects, and (8) the logical development of thought or reality through thesis and antithesis to a synthesis of these opposites. Meaning (2) is notably still current, and the term is often used in a pejorative sense.

In the following discussion the different kinds of dialectic will be elucidated in their historical order.

Socrates and his Predecessors

Dialectic perhaps originated in the fifth century BCE, since Zeno of Elea, the author of the famous paradoxes, was recognized by Aristotle as its inventor (Diogenes Laërtius, Lives VIII, 57). Aristotle presumably had Zeno's paradoxes in mind, as they are outstanding examples of dialectic, in the sense of refutation of the hypotheses of opponents by drawing unacceptable consequences from those hypotheses. For example, it is unacceptable that Achilles never overtakes the tortoise; therefore, the hypothesis that leads to this conclusion must be rejected. Insofar as this method relies on the law of formal logic known as modus tollens (if p implies q, and q is false, then p is false), Zeno was a pioneer of logic, but there is no evidence that he could formulate the law itself; it was left to Aristotle later to state explicitly the principles that underlie this kind of dialectic, and thus to create the science of formal logic.

Dialectic as the use of such indirect logical arguments to defeat an opponent seems to have been used by Zeno for serious philosophical purposes, but it later became, in the hands of the Sophists, a mere instrument for winning a dispute. For example, the Sophist Protagoras claimed that he could "make the worse argument appear the better"; such an aim belongs rather to rhetoric than to logic or philosophy. This degenerate form of dialectic was named "eristic" by Plato (for example, in Sophist 231e) and others, from the word ρις (strife). Eristic came to make deliberate use of invalid argumentation and sophistical tricks, and these were ridiculed by Plato in his dialogue Euthydemus, which takes its name from an actual Sophist who appears in it as a user of eristic arguments. Aristotle, too, thought the Sophists worth answering in his book De Sophisticis Elenchis (Sophistical refutations), although he sharply distinguished eristic from dialectic, dialectic being for him a respectable activity.

If, however, the lost work of Protagoras did begin, as several subsequent writers attest, with the claim that on every subject two opposite statements (λόγοι ) could be made, and if the book continued with a content of statement and counterstatement, then Protagoras deserves to be considered the ancestor of the medieval or of the Hegelian dialectic rather than the father of eristic.

Socrates stands in contrast to the Sophists. Unlike them, he professed to be seeking the truth. But he was not above winning the argument, and what is called the elenchus was a major element in dialectic as practiced by him, if we are to accept as accurate the presentation of him in Plato's earlier dialogues. The Socratic elenchus was perhaps a refined form of the Zenonian paradoxes, a prolonged cross-examination that refutes the opponent's original thesis by getting him to draw from it, by means of a series of questions and answers, a consequence that contradicts it. This is a logically valid procedure, for it corresponds to the logical law "if p implies not-p, then not-p is true (that is, p is false)." Dialectic seems to have been, for Socrates, literally the art of discussion, a search for truth by question and answer; but the definition of a concept is the sort of truth that was typically sought by him, and he supplemented his elenchus with another technique, later called epagoge (παγωγή ) by Aristotle. This consisted in leading the opponent on to a generalization by getting him to accept the truth of a series of propositions about particular cases. It may now be seen why, in discussing dialectic, Aristotle says "there are two innovations that may justly be ascribed to Socrates: epagogic arguments and universal definition" (Metaphysics M 4, 1078b). For Aristotle had a different conception of dialectic, and since elenchus goes back to Zeno, the two features he mentions are the only contributions made by Socrates to dialectic as Aristotle understood it. The Socratic irony, or pretense not to know anything and not to be conducting a refutation, was a personal feature of Socrates' dialectic and contributed nothing to later developments.


In the middle dialogues of Plato there occurs a development of the notion of dialectic beyond what we take to be typical of the historical Socrates. Even though Socrates is the protagonist, the views he is portrayed as putting forward are presumably those of Plato. Dialectic is regarded there as the supreme philosophical method, indeed the highest of human arts: it is "the coping-stone, as it were, placed above the sciences" (Republic 534e). In the Cratylus Plato had described the dialectician as "the man who knows how to ask and answer questions" (390c), and this view of dialectic as question and answer is the Socratic element that forms the single thread running through his altering conceptions of the method. Furthermore, dialectic always had the same subject matter: it sought the unchanging essence of each thing. But the kind of reasoning that Plato regarded as involved in dialectic seems to change: In the middle dialogues it was some kind of operation on hypotheses, whereas in the later ones (for example, Phaedrus and Sophist ) there is, instead, an emphasis on division (διαίρεσις ) as a method. Division in effect consists of a repeated analysis of genera into species, of more general notions into less general ones, as a way of arriving at a definition when no further division is possible. This process is complemented by the opposite process of synthesis or collection (συναγωγή ).

Although Plato always spoke of dialectic in an extremely favorable manner, his discussion of it in Republic VIVII marks a high point, as it is there made to be the distinguishing feature in the education of the philosopher-kings and is to be concerned eventually with the supreme Form, that of the Good. It is to reach certainty and overcome the need for hypotheses (Republic 511b). But the elevation of the sentiments expressed is matched by suitable vagueness as to the exact process involved, and the interpretation of the few words that are at all precise has been greatly disputed.

It may seem that if dialectic is a process of discussion, then it cannot be of any use for private thought. For Plato, however, there was no difference between the two: "Thought and speech are the same thing, but the silently occurring internal dialogue of the soul with itself has been specially given the name of thought" (Sophist 263e; see also Theaetetus 189e). However, Plato's most important pupil, Aristotle, was already taking a different view of the nature of thought and hence assigning a merely secondary role to dialectic: "Deception occurs to a greater extent when we are investigating with others than by ourselves, for an investigation with someone else is carried on by means of words, but an investigation in one's own mind is carried on quite as much by means of the thing itself" (De Sophisticis Elenchis 169a37). Dialectic was no longer to be the method of science.


The practice of dialectic was probably a major activity in Plato's Academy, to which Aristotle belonged from 367 BCE until Plato's death in 347. Aristotle's Topics was apparently intended as an aid to this dialectical debate. It is a handbook for finding arguments to establish or demolish given positions, or theses, such as "Every pleasure is good," and while the particular theses used as examples in the Topics are no doubt borrowed from the debates in the Academy, the methods provided for dealing with them are completely general, that is, applicable to any thesis of the same form. The Topics is therefore the first systematic account of dialectic, and Aristotle indeed boasted that prior to his own treatment of the subject "it did not exist at all" (De Sophisticis Elenchis 183b36), and criticized the Sophists for giving teaching that was unsystematic (τεχνος ). His own trend toward generality and system had the effect that in the Topics Aristotle discovered many basic principles of formal logic, including some in the propositional calculus and in the logic of relations, but he hardly reached an explicit formal statement of them. A large part, at least, of this work was written before his discovery of the (categorical) syllogism, a type of argument for which he developed, in his Analytics, an elaborate systemthe earliest system of formal logicthat superseded dialectic as a theory of demonstration. But even if Aristotle's formal logic developed as an alternative to his dialectic, it may still have arisen out of dialectic in some sense, since it has been argued that he discovered the syllogism as a result of reflection on Plato's method of division.

The distinguishing feature of dialectic for Aristotle was not so much the type of reasoning as the epistemological status of the premises. Reasoning is dialectical if its premises are opinions that are generally accepted by everyone or by the majority or by philosophers; if the premises merely seem probable, or if the reasoning is incorrect, then it is "eristic." Aristotelian dialectic is thus quite respectable; it has even been called a "logic of probability," a name that could be misleading because dialectic does not in fact involve inductive reasoning. However, dialectic is not good enough, Aristotle believed, to be a method of acquiring knowledge proper, or science. For that we require demonstration, which is valid reasoning that starts out from true and self-evident premises. The value of dialectic, according to Aristotle, is threefold: It is useful for intellectual training, for discussions with others based on their own premises, and for examining the unprovable first principles of the sciences. "Dialectic, being a process of criticism, contains the path to the principles of all inquiries" (Topics 101b3).

Stoics and Medievals

Euclides of Megara (a contemporary of Plato) and his successors in that town were logicians of note, and the Megarian tradition in logic was continued by the Stoics. The Stoic logic was known as dialectic, perhaps because the initiators of their tradition had an interest in the Zenonian paradoxes and related reasoning. Under the headship of Chrysippus, who lived from 280 to 206 BCE, the Stoic school reached its zenith, and it was still going strong four centuries later. A saying is recorded from this period, that "if the gods had dialectic, it would be the dialectic of Chrysippus" (Diogenes Laërtius, Lives VII, 180). By "dialectic" the Stoics primarily meant formal logic, in which they particularly developed forms of inference belonging to what we now call the propositional calculus. But they applied the term dialectic widely: for them it also included the study of grammatical theory and the consideration of meaning-relations and truth. This widened scope, reflecting the special interests of the early Stoics, remained typical of the school; it was accepted by Cicero and perhaps overemphasized by Seneca, who wrote that dialectic "fell into two parts, meanings and words, that is, things said and expressions by which they are said"διαλεκτική in duas partes dividitur, in verba et significationes, id est in res quae dicuntur et vocabula quibus dicuntur (Epistulae Morales 89, 17).

In the Middle Ages "dialectic" continued to be the ordinary name for logic: for example, the first medieval logical treatise was the Dialectica of Alcuin. But the word logica was also used; in fact, Abelard wrote a Dialectica and more than one Logica. As the works of Plato and Aristotle became known, the Scholastics took over various conceptions of dialectic, and the medieval disputation, by which university degree examinations were conducted, can be regarded as a remote descendant or revival of the debates in the Platonic Academy. The disputants maintained theses and antitheses, arguing mainly in syllogisms; the most significant difference from ancient practice was that the class of unacceptable consequences now included those propositions that were inconsistent with divine revelation.

Kant and his Successors

In his Critique of Pure Reason (A61, B85) Immanuel Kant asserted rather sweepingly that the actual employment of dialectic among the ancients was always as "the logic of illusion (Logik des Scheins )." He explained that he applied the term to logic as a critique of dialectical illusion. He titled the second division of his Transcendental Logic "Transcendental Dialectic." This new kind of dialectic was concerned with exposing the illusion of transcendental judgments, that is, judgments that profess to pass beyond the limits of experience; but the illusion can never, he thought, be dispelled entirely, as it is natural and inevitable.

Although Kant, in his Transcendental Dialectic, had set out the antinomies of pure reason as four sets of thesis and antithesis, he did not call his resolution of the antinomies a synthesis. It was his successor Johann Gottlieb Fichte who, in his Grundlage der gesamten Wissenschaftslehre (Jena and Leipzig, 1794), first introduced into German philosophy the famed triad of thesis, antithesis, and synthesis. In this he was followed by Friedrich Schelling, but not in fact by G. W. F. Hegel. Fichte did not believe that the antithesis could be deduced from the thesis; nor, on his view did the synthesis achieve anything more than uniting what both thesis and antithesis had established.

Hegel and his Successors

Hegel is commonly supposed to have presented his doctrines in the form of the triad or three-step (Dreischritt ) of thesis, antithesis, and synthesis. This view appears to be mistaken insofar as he did not actually use the terms; and even though he evinced a fondness for triads, neither his dialectic in general nor particular portions of his work can be reduced simply to a triadic pattern of thesis, antithesis, and synthesis. The legend of this triad in Hegel has been bolstered by some English translations that introduce the word antithesis where it is not required.

However, there is indeed a Hegelian dialectic, involving the passing over of thoughts or concepts into their opposites and the achievement of a higher unity. But if it is a process that arrives at a higher truth through contradictions, it does not constitute a new conception of dialectic. Hegel actually showed his awareness of the traditional notion by paying tribute to "Plato's Parmenides, probably the greatest masterpiece of ancient dialectic." And even the doctrine that dialectic is a world processnot merely a process of thought but also found in history and in the universe as a wholewas not wholly new, but goes back to Heraclitus and the Neoplatonist Proclus. Here again Hegel, with his interest in the history of philosophy, was aware of his predecessors. What seems to be genuinely new in Hegel's view of dialectic is the conception of a necessary movement. Dialectic was said to be "the scientific application of the regularity found in the nature of thought." The "passing over into the opposite" was seen as a natural consequence of the limited or finite nature of a concept or thing. The contradictions in thought, nature, and society, even though they are not contradictions in formal logic but conceptual inadequacies, were regarded by Hegel as leading, by a kind of necessity, to a further phase of development.

Hegel has had an enormous influence not only on willing disciples but even on thinkers nominally in revolt against him, such as Søren Kierkegaard. One of the most important offshoots of the Hegelian dialectic was the Marxist dialectic, in which, of course, "matter" was substituted for Hegel's "spirit."

See also Abelard, Peter; Aristotle; Chrysippus; Cicero, Marcus Tullius; Dialectical Materialism; Diogenes Laertius; Fichte, Johann Gottlieb; Greek Academy; Hegel, Georg Wilhelm Friedrich; Hegelianism; Heraclitus of Ephesus; Infinity in Mathematics and Logic; Kant, Immanuel; Kierkegaard, Søren Aabye; Marxist Philosophy; Medieval Philosophy; Neoplatonism; Plato; Proclus; Protagoras of Abdera; Schelling, Friedrich Wilhelm Joseph von; Socrates; Sophists; Stoicism; Zeno of Elea.


general discussions

For general discussions of dialectic, see Paul Foulquié, La dialectique (Paris, 1949); Eduard von Hartmann, Über die dialektische Methode (Berlin, 1868; 2nd ed. 1910); Karl Dürr, "Die Entwicklung der Dialektik von Plato bis Hegel." Dialectica 1 (1947); and Jonas Cohn, Theorie der Dialektik (Leipzig, 1923).

socrates and his predecessors

On Zeno, see H. D. P. Lee, Zeno of Elea (Cambridge, U.K., 1936); G. E. L. Owen, "Zeno and the Mathematicians," in PAS 58 (19571958): 199222; and John Burnet, Early Greek Philosophy (London, 1892; 4th ed., 1930). For the period before Socrates as a whole, see Burnet's From Thales to Plato (London, 1914). For criticisms of the Sophists, see Plato, Euthydemus, and Aristotle, De Sophisticis Elenchis, translated by W. A. Pickard-Cambridge in The Works of Aristotle, Vol. 1 (Oxford, 1928). On this whole phase of dialectic, see the extremely reliable work of William and Martha Kneale, The Development of Logic (Oxford: Clarendon Press, 1962), Ch. 1.


The most helpful book on Plato's use of dialectic is Richard Robinson, Plato's Earlier Dialectic (Ithaca, NY: Cornell University Press, 1941; 2nd ed., Oxford: Clarendon Press, 1953), but the word earlier occurs in its title because it contains no examination of the methods of division and synthesis that appear in some of Plato's later dialogues. For the original descriptions of the Platonic dialectic, see the Dialogues of Plato, passim (in any translation), but above all the Republic, Books VIVII, especially 510540 in the standard numbering. See also James Adam, The Republic of Plato, Vol. II (Cambridge, U.K., 1902; reissued, 1963), pp. 168179; Richard Lewis Nettleship, Lectures on the Republic of Plato (London: Macmillan, 1901), pp. 277289; Julius Stenzel, Studien zur Entwicklung der Platonischen Dialektik von Sokrates zu Aristoteles (Breslau, 1917; 2nd ed., 1931), translated by D. J. Allan as Plato's Method of Dialectic (Oxford: Clarendon Press, 1940; reissued, New York: Russell and Russell, 1964); Francis M. Cornford, "Mathematics and Dialectic in the Republic VIVII," in Mind 41 (1932): 3752, 173190; R. S. Bluck, "ποθέσεις in the Phaedo and the Platonic Dialectic," in Phronesis 2 (1) (1957): 2131; D. W. Hamlyn, "The Communion of Forms and the Development of Plato's Logic," in Philosophical Quarterly 5 (1955): 289302; Georges Rodier, "Les mathématiques et la dialectique dans le système de Platon," in Archiv für Geschichte der Philosophie 15 (1902): 479490, and his "L'évolution de la dialectique de Platon," in Année philosophique (1905): 4973; D. S. Mackay, "The Problem of Individuality in Plato's Dialectic," in University of California Publications in Philosophy 20 (1937): 131154; and Juan A. Nuño Montes, La dialéctica platónica (Caracas, 1962).


For the original account, see Aristotle, Topica, translated by W. A. Pickard-Cambridge in The Works of Aristotle, Vol. I (Oxford, 1928). The most accessible scholarly discussion of this phase is Ernst Kapp, Greek Foundations of Traditional Logic (New York: Columbia Press, 1942). Important treatments of the controversial issues involved are Friedrich Solmsen, Die Entwicklung der Aristotelischen Logik und Rhetorik (Berlin, 1929), his "The Discovery of the Syllogism," in Philosophical Review 50 (1941): 410421, and his "Aristotle's Syllogism and Its Platonic Background," in Philosophical Review 60 (1951): 563571; and Paul Wilpert, "Aristoteles und die Dialektik," in Kant-Studien 68 (1956): 247284. There is also Livio Sichirollo, Giustificazioni della dialettica in Aristotele (Urbino, 1963).

stoics and medievals

For a discussion of Stoic use of dialectic, see Benson Mates, Stoic Logic (Berkeley: University of California Press, 1953). For a general account of the medieval phase and references to particular works, see William and Martha Kneale, op. cit., Ch. 4. For the postmedieval rejection of dialectic, see Duane H. Berquist, "Descartes and Dialectics," in Laval théologique et philosophique 20 (2) (1964): 176204.

kant and his successors

Kant and his successors are discussed in Graham H. Bird, Kant's Theory of Knowledge (London: Routledge and Paul, 1962); John E. Llewelyn, "Dialectical and Analytical Opposites," in Kant-Studien 55 (1964): 171174; and Richard Kroner, Von Kant bis Hegel, 2 vols. (Tübingen, 19211924).

hegel and his successors

For general discussions of the Hegelian phase, see K. R. Popper, "What Is Dialectic?," in Mind 49 (1940): 403426, reprinted in Popper's Conjectures and Refutations (London: Routledge, 1963); Sidney Hook, "What Is Dialectic?," in Journal of Philosophy 26 (1929): 8599, 113123, his From Hegel to Marx (London, 1936), and his "Dialectic in Social and Historical Inquiry," in Journal of Philosophy 36 (1939): 365378; and Siegfried Marck, Die Dialektik in der Philosophie der Gegenwart, 2 vols. (Tübingen, 19291931). On dialectic in Hegel, see John M. E. McTaggart, Studies in the Hegelian Dialectic (Cambridge, U.K., 1896); G. R. G. Mure, An Introduction to Hegel (Oxford: Clarendon Press, 1940); and above all, John N. Findlay, "Some Merits of Hegelianism," in PAS 56 (19551956): 124, and his Hegel: A Re-examination (London: Allen and Unwin, 1958), and a valuable chapter by him on Hegel in A Critical History of Western Philosophy, edited by D. J. O'Connor (London, 1964). See also Gustav E. Mueller, "The Hegel Legend of Thesis-Antithesis-Synthesis," in Journal of the History of Ideas 19 (1958): 411414; Carl J. Friedrich, "The Power of Negation: Hegel's Dialectic and Totalitarian Ideology," in A Hegel Symposium, edited by D. C. Travis (Austin: University of Texas, 1962), pp. 1335; and Walter Kaufmann, Hegel (New York, 1965). On Marx, see Harold B. Acton, The Illusion of the Epoch: MarxismLeninism as a Philosophical Creed (London: Cohen and West, 1955).

Roland Hall (1967)

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