Megarian school

From New World Encyclopedia

The Megarian School of philosophy was founded c. 400 B.C.E. by Euclides of Megara, an early Hellenistic philosopher and one of the pupils of Socrates. Starting with the Socratic principle that virtue is knowledge, Euclides went on to define knowledge as a transcendental entity divorced from the sphere of sense and experience. The Megarians conducted their investigations by means of dialectic, applying logic to Knowledge, and believed that ideas were eternal and immovable.

Two disciples of Euclides— Eubulides and Alexinus—developed the use of dialectic to such extremes that they were accused of being argumentative and eristic. Eubulides devised a series of paradoxes, including the famous liar paradox and the sorites (heap) paradox. Alexinus was a critic of Zeno of Citium and often provoked him with arguments that arrived at reducto ad absurdum. Stilpo, also famous for disputation, preached self-reliance and indifference to pain or pleasure, and was one of the teachers of Zeno of Citium. Diodorus was one of the first to explore propositional logic, strongly influencing the Stoics and the Skeptics.

The Megarian School

The Megarian School was a loosely associated group of dialecticians whose activities spanned a century during the late fourth and early third centuries B.C.E. Euclides founded a school of disputation at Megara, and Stilpo was also a Megarian, but the members of the school lived and taught in Athens and other cities. The Megarians did not practice a particular lifestyle, but devoted themselves to intellectual exploration and the development of propositional logic. Among the Megarians are Eubulides and Alexinus, who are credited with developing several paradoxes and with using dialectic to criticize the Stoics; Euphantus, a teacher of the king Antigonus; Diodorus, credited with developing the Master Argument; Icthyas; Clinomachus; and Stilpo, who combined the Cynic concept of a life lived according to nature with the Eleatic ideal of the Megarians and set an example of a life of indifference to physical circumstances and the pursuit of virtue.

The logic of the Megarians had a profound impact on the development of ancient philosophy. In his arguments, Euclides rejected analogical reasoning and preferred to deduce conclusions from acknowledged premises. The methodology of discovering truth through questioning established concepts, and of using propositional logic to determine the validity of certain ideas, has continued in use to the present day. The Megarians were frequently called upon to use their disputational skills in arguing cases in the courts of civil law.



Euclides, who died in 365 B.C.E., was born at Megara. He studied the teachings of Parmenides, then moved to Athens and became a pupil and close associate of Socrates. There was a political disagreement between Athens and Megara, and the Athenians passed a decree that any Megarian entering their city would be put to death. Euclides moved to a village twenty miles outside of Athens and would secretly enter Athens at night, disguised as a woman in a long cloak and veil, in order to be instructed by Socrates. Euclides conducted his philosophical investigations using dialectic, and Socrates once chastised him for his fondness for argument. Apparently Euclides frequently argued business cases in the civil courts. Though he excelled at disputation, a story about him attests to his good character. After an incident in which he angered his brother, his brother said, "Let me perish if [I] do not have revenge on you." To this Euclides replied, "And let me perish if I do not subdue your resentment by forbearance, and make you love me as much as ever."

He eventually established a school in Megara where he taught the art of disputation, and it is for this school that the Megarians are named. A number of Socrates’ pupils, including Plato, joined him there after the execution of Socrates, probably in fear of their lives if they remained in Athens.

Eubulides and Alexinus

Two of Euclides’ followers, Eubulides and Alexinus, developed dialectic to such an extreme that they were often ridiculed and labeled eristic. Eubulides of Miletus developed a number of well-known paradoxes, including the liar paradox (Is the man a liar who says that he tells lies? If he is, then he does not tell lies; and if he does not tell lies, is he a liar?), the veiled paradox (You do not know a woman who is veiled; she is your mother; therefore you do not know your mother.) and the horned paradox (You have what you have not lost; you have not lost horns; therefore you have horns.). One of the most well-known is the sorites (or heap) paradox, which exists in a variety of forms in ancient philosophy and has led to the development of “fuzzy logic” in modern philosophy.

Alexinus of Elis was a leading critic of Zeno of Citium, founder of Stoicism, and often used reducto ad absurdum to parody his arguments. According to Diogenes Laertius in Lives of Eminent Philosophers, his fondness for argument earned him the nickname Elenchino (from elenchô, to confute).


Stilpo (c. 380 – c. 300 B.C.E.), a native of Megara, was also a skilled dialectician, but he was most famous for preaching self-reliance. Diogenes Laertius says that Stilpo “…was so much superior to all his fellows in command of words and in acuteness, that it may almost be said that all Greece fixed its eyes upon him, and joined the Megaric school.” He apparently won over disciples from several of the philosophical schools in Athens, and was a powerful influence on Crates the Cynic and Zeno of Citium. According to Diogenes he was a “witty and elegant-minded man” who attracted all the citizens to such a degree, that they used to run from their workshops to look at him.” Stilpo was famous for his "apatheia," or indifference to pain or pleasure. According to one story, when Demetrius invaded Megara the house of Stilpo was plundered by his troops. Demetrius ordered the house to be spared, and asked Stilpo for a list of everything that he had lost, so that his possessions could be restored to him. Stilpo answered, “…he had lost nothing of his own; for that no one had taken from him his learning, and that he still had his eloquence and his knowledge.”


Another important Megarian was Diodorus of Iasos (late fourth to early third centuries B.C.E.), one of the first to explore propositional logic. He and his associates became known as the Dialectical school and were distinguished by the originality of their thought. He held that a conditional is true only if it is not possible and has never been possible that the first proposition is true and the second is false. He defined the possible as what either is or will be true, and the necessary as what is true and will never be false. Based on these definitions he developed the master (or ruling) argument: the past is necessary; the impossible cannot follow the possible; therefore no proposition is possible unless it is, or will be, true. Many Stoics felt this argument was too fatalistic and challenged the idea that the “the impossible cannot follow from the possible.”

Diogenes Laertes reports that Diodorus was attending a banquet at the court of Sodor Ptolemy when Stilpo posed him several dialectic questions to which he was not able to give an immediate answer. The king scolded him harshly, and Diodorus left the banquet, wrote an essay on Stilpo’s question, and died of shame.

Knowledge and Goodness

Euclides, who had carefully studied the writings of Parmenides, combined the Eleatic doctrine of unity with the Socratic principle that virtue is knowledge. He identified the “Being,” or “One,” with the “Good” of Socrates, and said that it could be called several names: “reason,” “mind,” “god,” and “wisdom.” Knowledge meant knowledge of the “One,” or the “Good,” and all virtues such as temperance and benevolence were simply other names for the one virtue, Knowledge. Goodness alone existed; the opposite of Good did not exist. The “Good” was the essence of Being. Non-being, the opposite of Being, could not exist without itself becoming a type of being. Therefore the opposite of “Good” also could not exist. The Megarians used dialectic to disprove the possibility of motion and decay; unity is the negation of change, increase and decrease, birth and death. Matter and motion and other sensory experiences did not exist, and were separate from Being. The “Good” was beyond the sphere of sensible apprehension.

ISBN links support NWE through referral fees

  • Dyeck. De Megaricorun doctrina. Bonn, 1827.
  • Gomperz, Theodor. Greek Thinkers (Eng. trans. 1905), ii. 170 seq. Thoemmes Continuum, June 1997.
  • Mallet. Henne, Histoire de l'école de Mégare. Paris, 1845.
  • Prantl. Geschichte der Logik, i. 32; Henne, L'école de Mégare, Paris, 1843.
  • Ritter. Uber die Philosophie der Meg. Schule
  • Zeller, Eduard. Socrates and the Socratic School. Russell & Russell Pub, June 1962.


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