The Megarians flourished during the fourth and the early third centuries BCE. They derived their name from their connection with Megara on the Isthmus (a city one day's walk west of Athens). They constituted a 'philosophical school' only in a weak sense: no shared lifestyle, no rigid body of doctrine. Since no work of any Megarian has survived, knowledge of them must rely on fragments and reports of other authors.
The earliest Megarian was Euclides of Megara. Diogenes Laertius (2.106) reports that Euclides' followers "were called 'Megarians,' then 'Eristics,' and later 'Dialecticians.'" Modern scholars traditionally understood this report as indicating that a single school had three successive labels. However, in 1977 David Sedley argued that the three labels designated three distinct groups of philosophers that were influenced to some extent by Euclides but, far from constituting a single school, were in competition with one another. Sedley's reconstruction has won widespread, although not universal, scholarly approval. The present entry will cover all those thinkers who have traditionally been regarded as Megarians, including Eristics and Dialecticians, except the Dialecticians Diodorus and Philo, who have separate entries.
Euclides of Megara was probably born after 450 BCE and died before 365 BCE. A pupil of Socrates, he also studied Parmenides' writings. He is mentioned by Plato in the Phaedo (59b–59c), where he is portrayed as present at Socrates' death, and in the Theaetetus (142a–143c), where he is described conversing with Terpsion, another early Megarian. After Socrates' death, Plato and some of his companions fled Athens to stay for awhile with Euclides at Megara. Euclides authored six dialogues: Lamprias, Aeschines, Phoenix, Crito, Alcibiades, and a Discourse on Love. We know little of Euclides' philosophical views. He claimed that the good is one although it is called by many names (such as 'wisdom,' 'God,' and 'mind'), and that the contrary of the good is mere nonbeing: he thus seems to have borrowed Socratic views in ethics and combined them with Eleatic monism. He attacked proofs by opposing their conclusions, not their premises (he probably did this by reducing to absurdity the conclusions, wherein an influence of the methods of Zeno of Elea can be detected), and he rejected arguments from parallel cases.
Euclides had numerous pupils: Dionysius of Chalcedon, Dioclides of Megara, Thrasymachus of Corinth, Ichthyas, and Clinomachus of Thurii, who founded the Dialectical school. According to Diogenes Laertius (2.112), Clinomachus was "the first who wrote about assertibles, predicates, and the like." Later, in Stoic logic, assertibles and predicates are two of the main types of sayables, incorporeal items that are signified by utterances of linguistic expressions and are themselves neither thoughts nor linguistic expressions (specifically, assertibles and predicates are what is signified, respectively, by utterances of declarative sentences and predicative expressions). It is unclear how much of the Stoic views about assertibles and predicates was already held by Clinomachus, but it cannot be ruled out that the basics were already in place.
According to some sources, one of Euclides' pupils was named 'Bryson.' Modern scholars disagree on whether there was exactly one thinker answering to this name, and whether he is the same as the one who introduced a method for squaring the circle which was criticized by Aristotle.
Later Dialecticians were Polyxenus (to whom the authorship of a 'third man' argument against forms is ascribed) and Eubulides of Miletus. Since he taught Demosthenes and wrote a defamatory book against Aristotle, Eubulides was probably born in the second half of the fourth century BCE. According to Diogenes Laertius (2.108), he fathered seven arguments: the Liar, the Disguised, the Electra, the Veiled, the Heaper, the Horned, and the Baldhead. These arguments, in question-and-answer form, were extensively discussed by later Hellenistic philosophers.
It is not clear whether Eubulides' version of the Liar had already the devastating self-referential character of modern versions. For instance, we cannot rule out that Eubulides' version was presented roughly as follows: The questioner makes an obviously false statement, adds the remark 'I am speaking falsely,' and then asks whether he is speaking truly or falsely—both answers can be regarded as correct with regard to different statements made by the questioner. Note that all ancient versions of the Liar turn on the sentence 'I am speaking falsely' (modern versions instead turn on 'This sentence is false' or variants thereof). The Heaper heaps questions concerning heaps: 'Does one grain constitute a heap?' 'Do two grains constitute a heap?' 'Do ten thousand grains constitute a heap?' One is likely to answer the first question negatively, and then, on the assumption that the addition of a single grain cannot transform what is not yet a heap into one, is induced to answer negatively each of the following.
The Baldhead was probably an alternative formulation of the same puzzle. On the basis of Lucian (Vitarum Auctio, 22–23), we can plausibly reconstruct the Veiled as follows: 'Do you know your father?—Yes.—If I set a veiled man before you and I ask you whether you know him, what do you answer?—That I do not know him.—But the veiled man is your father. So, you both know and do not know your father.' The Disguised and Electra were probably variants of the Veiled. On the basis of Diogenes Laertius (7.187), we can plausibly reconstruct the Horned as follows: 'If you have not lost something, do you still have it?—Yes.—Have you lost horns?—No.—Then you still have horns.'
Pupils of Eubulides were Euphantus of Olinthus, Apollonius, surnamed 'Cronus' (his pupil Diodorus inherited this surname from him), and Alexinus of Elis, whose fondness of controversy earned him the nickname 'Elenxinus' ('Refuter'). Some sources describe Alexinus as a Dialectician, others as an Eristic. Active around 300 BCE, he wrote a book On Education and works against other thinkers, Aristotle and Zeno of Citium among them. Alexinus attacked Zeno by taking arguments of his and constructing unpalatable 'parallels,' namely arguments that were isomorphic to Zeno's and had plausible premisses but absurd conclusions. For instance, Zeno had offered the following argument: 'What is rational is better than what is not rational; but nothing is better than the universe; therefore, the universe is rational' (Sextus Empiricus, Adversus Mathematicos, 9.104).
Alexinus constructed the following parallel: 'What is poetic is better than what is not poetic; but nothing is better than the universe; therefore the universe is poetic' (Sextus Empiricus, Adversus Mathematicos, 9.108). Zeno was thereby left with two options: either claim that his argument is valid whereas Alexinus's parallel is not, or claim that all the premisses of his argument are true whereas at least one of Alexinus's parallel is not. The first option was hard to follow because the two arguments are extremely similar (in fact, neither of them is valid in first-order logic as it stands, but becomes such if an uncontroversial premise is added: 'Something is rational' in the case of Zeno's argument, 'Something is poetic' in the case of Alexinus's parallel). Sextus Empiricus (Adversus Mathematicos, 9.109–110) reports that Zeno's followers chose the second option: they insisted that all the premisses of Zeno's argument are true but one of Alexinus's parallel is not.
Little is known of Panthoides, a Dialectician who flourished around 300–280 BCE. The last Megarian about whom we are relatively well informed is Stilpo of Megara, who probably lived between 360 and 280 BCE. According to Diogenes Laertius (2.113), "so far did he excel everyone else in inventiveness and sophistry that nearly the whole of Greece was looking at him and Megarizing." He had many pupils, Zeno of Citium and Menedemus of Eretria among them, and wrote many dialogues. According to Plutarch (Adv. Colotem, 23, 1120a), Stilpo claimed that what is predicated must be identical with what it is predicated of. For example, goodness cannot be predicated of a man because it is not identical with him, nor can running be predicated of a horse because it is not identical with it. Stilpo's attack on predication recalls a position criticized by Plato in the Sophist (251a–c), and therefore lends plausibility to identifying Plato's target with some Megarian earlier than Stilpo. Stilpo attacked forms. One of his arguments can perhaps be reconstructed on the basis of Diogenes Laertius (2.119) and Alexander of Aphrodisias (Commentary on Aristotle's Metaphysics, 84, 7–14). Suppose that individual perceptible men and the form Man were the only men. It is surely true that man speaks. But who is then the man who speaks? Nobody: for it is none of the particular perceptible men (for why should it be this one rather than this one?), and it is not the form Man (for forms do not speak). If we want to avoid denying that man speaks, we must give up the assumption that individual perceptible men and the form Man are the only men, and therefore introduce a 'third man.' This seems to undermine our motivation for assuming there is the form Man.
According to Diogenes Laertius (2. 115), when Demetrius Poliorcetes had taken Megara and wanted Stilpo to list the items he had lost, "he said that he had lost nothing of his own: for nobody had subtracted his learning, and he still had reason and knowledge." This anecdote suggests that for Stilpo the only human goods are moral and intellectual attainments, which are inalienable (a view close to that of the Cynics).
In the Metaphysics (9. 3, 1046b29–32), Aristotle attributes to unnamed Megarians the view that a thing has the capacity to do something when and only when it is actually doing it. For example, whenever the builder is building, he also has the capacity to build, but when he is not building, he lacks the capacity to build. We are unable to link this view to any specific Megarian, and the ideas about modality we can ascribe to Diodorus Cronus and Philo do not chime with it.
See also Alexander of Aphrodisias; Cynics; Diodorus Cronus; Diogenes Laertius; Hellenistic Thought; Parmenides of Elea; Philo of Megara; Plato; Plutarch of Chaeronea; Socrates; Sextus Empiricus; Stoicism; Zeno of Citium; Zeno of Elea.
collections of fragments
Döring, K. Die Megariker. Kommentierte Sammlung der Testimonien. Amsterdam: Grüner 1972.
Giannantoni, Gabriele. Socratis et Socraticorum reliquiae. 4 vols. Naples: Bibliopolis, 1990.
Döring, K. "Gab es eine Dialektische Schule?" (Was there a Dialectical School?). Phronesis 34 (1989): 293–310.
Makin, Stephen. "Megarian Possibilities." Philosophical Studies 83 (1996): 253–276.
Montoneri, Luciano. I Megarici: Studio storico-critico e traduzione delle testimonianze antiche. Catania, Italy: University of Catania, 1984.
Müller, Robert. Introduction à la pensée des Mégariques. Paris: Vrin, 1988.
Müller, Robert. Les Mégariques: fragments et témoignages. Paris: Vrin, 1985.
Schofield, Malcolm. "The Syllogisms of Zeno of Citium." Phronesis 28 (1983): 31–58.
Sedley, David. "Diodorus Cronus and Hellenistic Philosophy." Proceedings of the Cambridge Philological Society 203 (1977): 74–120.
Zeller, Eduard. Die Philosophie der Griechen in ihrer geschichtlichen Entwicklung dargestellt. 5th ed. Leipzig, Germany: Reisland, 1920—1923, 2.1, p. 244–275.
Paolo Crivelli (2005)