The Megarian school of philosophy (also called the Dialectical school), which flourished in the 4th century BC, was founded by Euclid of Megara

Euclid of Megara

Euclid of Megara was a Greek Socratic philosopher who founded the Megarian school of philosophy. He was a pupil of Socrates in the late 5th century BCE, and was present at his death. He held the supreme good to be one, eternal and unchangeable, and denied the existence of anything contrary to the...

, one of the pupils of Socrates

Socrates

Socrates was a classical Greek Athenian philosopher. Credited as one of the founders of Western philosophy, he is an enigmatic figure known chiefly through the accounts of later classical writers, especially the writings of his students Plato and Xenophon, and the plays of his contemporary ...

. Its ethical teachings were derived from Socrates, recognizing a single good, which was apparently combined with the Eleatic doctrine of Unity

Monism

Monism is any philosophical view which holds that there is unity in a given field of inquiry. Accordingly, some philosophers may hold that the universe is one rather than dualistic or pluralistic...

. Some of Euclid's successors developed logic

Logic

In philosophy, Logic is the formal systematic study of the principles of valid inference and correct reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, semantics, and computer science...

 to such an extent that they became a separate school, known as the Dialectical school. Their work on modal logic

Modal logic

Modal logic is a type of formal logic that extends classical propositional and predicate logic to include operators expressing modality. Modals — words that express modalities — qualify a statement. For example, the statement "John is happy" might be qualified by saying that John is...

, Logical conditionals, and propositional logic played an important role in the development of logic in antiquity.

History

The Megarian school of philosophy was founded by Euclid of Megara

Euclid of Megara

Euclid of Megara was a Greek Socratic philosopher who founded the Megarian school of philosophy. He was a pupil of Socrates in the late 5th century BCE, and was present at his death. He held the supreme good to be one, eternal and unchangeable, and denied the existence of anything contrary to the...

, who had been one of the pupils of Socrates

Socrates

Socrates was a classical Greek Athenian philosopher. Credited as one of the founders of Western philosophy, he is an enigmatic figure known chiefly through the accounts of later classical writers, especially the writings of his students Plato and Xenophon, and the plays of his contemporary ...

 in the late 5th century BC. His successors, as head of the school in Megara

Megara

Megara is an ancient city in Attica, Greece. It lies in the northern section of the Isthmus of Corinth opposite the island of Salamis, which belonged to Megara in archaic times, before being taken by Athens. Megara was one of the four districts of Attica, embodied in the four mythic sons of King...

, were said to have been Ichthyas

Ichthyas

Ichthyas , the son of Metallus, was a Greek philosopher and a disciple and successor of Euclid of Megara in the Megarian school. He was a colleague of Thrasymachus of Corinth in the school...

 (mid 4th century BC), and Stilpo

Stilpo

Stilpo was a Greek philosopher of the Megarian school. He was a contemporary of Theophrastus, Diodorus Cronus, and Crates of Thebes. None of his writings survive, he was interested in logic and dialectic, and he argued that the universal is fundamentally separated from the individual and concrete...

 (late 4th century BC). It is unlikely, however, that the Megarian school was a genuine institution, nor did it have a unified philosophical position. It was said that the philosophers of the school were first called Megarians and that later they were called Eristics, and then Dialecticians, but it is probable that these names designated splinter groups distinct from the Megarian school. Besides Ichthyas, Euclid's most important pupils were Eubulides of Miletus

Eubulides of Miletus

Eubulides of Miletus was a philosopher of the Megarian school, and a pupil of Euclid of Megara. He is famous for his paradoxes.-Life:Eubulides was a pupil of Euclid of Megara, the founder of the Megarian school. He was a contemporary of Aristotle, against whom he wrote with great bitterness...

 and Clinomachus of Thurii

Clinomachus

Clinomachus , was a Megarian philosopher from Thurii. He is said by Diogenes Laërtius to have been the first who composed treatises on the fundamental principles of dialectics, and he is described as the founder of the Dialectical school. According to the Suda, he was the disciple of Euclid of...

. It seems to have been under Clinomachus that a separate Dialectical school was founded, which placed great emphasis on logic

Logic

In philosophy, Logic is the formal systematic study of the principles of valid inference and correct reasoning. Logic is used in most intellectual activities, but is studied primarily in the disciplines of philosophy, mathematics, semantics, and computer science...

 and dialectic

Dialectic

Dialectic is a method of argument for resolving disagreement that has been central to Indic and European philosophy since antiquity. The word dialectic originated in Ancient Greece, and was made popular by Plato in the Socratic dialogues...

, and Clinomachus was said to have been "the first to write about proposition

Proposition

In logic and philosophy, the term proposition refers to either the "content" or "meaning" of a meaningful declarative sentence or the pattern of symbols, marks, or sounds that make up a meaningful declarative sentence...

s and predicates." However, Euclid himself taught logic, and his pupil, Eubulides, who was famous for employing celebrated paradox

Paradox

Similar to Circular reasoning, A paradox is a seemingly true statement or group of statements that lead to a contradiction or a situation which seems to defy logic or intuition...

es, was the teacher of several later dialecticians.

Via Stilpo, the Megarian school is said to have influenced the Eretrian school under Menedemus

Menedemus

Menedemus of Eretria was a Greek philosopher and founder of the Eretrian school. He learned philosophy first in Athens, and then, with his friend Asclepiades, he subsequently studied under Stilpo and Phaedo of Elis. Nothing survives of his philosophical views apart from a few scattered remarks...

 and Asclepiades

Asclepiades of Phlius

Asclepiades of Phlius was a Greek philosopher in the Eretrian school of philosophy. He was the friend of Menedemus of Eretria, and they both went to live in Megara and studied under Stilpo, before sailing to Elis to join Phaedo's school. His friendship with Menedemus was said to have been hardly...

, but the biggest influence was on Stoicism

Stoicism

Stoicism is a school of Hellenistic philosophy founded in Athens by Zeno of Citium in the early . The Stoics taught that destructive emotions resulted from errors in judgment, and that a sage, or person of "moral and intellectual perfection," would not suffer such emotions.Stoics were concerned...

. Zeno

Zeno of Citium

Zeno of Citium was a Greek philosopher from Citium . Zeno was the founder of the Stoic school of philosophy, which he taught in Athens from about 300 BC. Based on the moral ideas of the Cynics, Stoicism laid great emphasis on goodness and peace of mind gained from living a life of virtue in...

, the founder of the Stoic school, was said to have studied under Stilpo and Diodorus Cronus

Diodorus Cronus

Diodorus Cronus was a Greek philosopher and dialectician connected to the Megarian school. He was most notable for logic innovations, including his master argument fomulated in response to Aristotle's discussion of future contingents.-Life:...

, and to have disputed with Philo the Dialectician

Philo the Dialectician

Philo the Dialectician was a dialectic philosopher of the Megarian school. He is often called Philo of Megara although the city of his birth is unknown...

. It was perhaps the Dialecticians, Diodorus and Philo, who were the biggest influence on the development of Stoic logic, and that Zeno studied under Stilpo to learn his moral teachings, although Stilpo, too, is said to have excelled "in the invention of arguments and in sophistry."

Philosophy

Euclid had been a pupil of Socrates, but ancient historians also regarded him as a successor to the Eleatics

Eleatics

The Eleatics were a school of pre-Socratic philosophers at Elea , a Greek colony in Campania, Italy. The group was founded in the early fifth century BCE by Parmenides. Other members of the school included Zeno of Elea and Melissus of Samos...

, hence his philosophy was seen as a fusion of Eleatic and Socratic thought. Thus the Eleatic idea of "The One" was identified with the Socratic "Form of the Good," and the opposite of Good was regarded by Euclid as non-existent. But the emphasis of his thought is not on being but on the good, and idea that what is opposite to the good does not exist arises from the understanding of the good's unity. This theme is typically Socratic, what matters is the moral good and the will of the good person to strive towards it. Stilpo is said to have continued the Eleatic tendency, by asserting a strict monism

Monism

Monism is any philosophical view which holds that there is unity in a given field of inquiry. Accordingly, some philosophers may hold that the universe is one rather than dualistic or pluralistic...

 and denying all change and motion, and he also rejected Plato

Plato

Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...

's Theory of Forms

Theory of Forms

Plato's theory of Forms or theory of Ideas asserts that non-material abstract forms , and not the material world of change known to us through sensation, possess the highest and most fundamental kind of reality. When used in this sense, the word form is often capitalized...

. In ethics

Ethics

Ethics, also known as moral philosophy, is a branch of philosophy that addresses questions about morality—that is, concepts such as good and evil, right and wrong, virtue and vice, justice and crime, etc.Major branches of ethics include:...

, Stilpo taught freedom, self-control, and self-sufficiency, approaching the teachings of the Cynics, another Socratic school.

Besides studying logical puzzles and paradoxes, the Dialecticians made two important logical innovations, by re-examining modal logic

Modal logic

Modal logic is a type of formal logic that extends classical propositional and predicate logic to include operators expressing modality. Modals — words that express modalities — qualify a statement. For example, the statement "John is happy" might be qualified by saying that John is...

, and by starting an important debate on the nature of conditional statement

Material conditional

The material conditional, also known as material implication, is a binary truth function, such that the compound sentence p→q is logically equivalent to the negative compound: not . A material conditional compound itself is often simply called a conditional...

s. This was the work of Diodorus Cronus

Diodorus Cronus

Diodorus Cronus was a Greek philosopher and dialectician connected to the Megarian school. He was most notable for logic innovations, including his master argument fomulated in response to Aristotle's discussion of future contingents.-Life:...

 and Philo the Dialectician

Philo the Dialectician

Philo the Dialectician was a dialectic philosopher of the Megarian school. He is often called Philo of Megara although the city of his birth is unknown...

, the only two members of the Dialectical school we have detailed information about. Through their development of propositional logic, the Dialectical school played an important role in the development of logic, which was an important precursor of Stoic logic.

External links

• The Dialectical School and the Origin of Propositional Logic with an annotated bibliography