The
Megarian school of philosophy, which flourished in the 4th century BC, was founded by
Euclid of Megara, one of the pupils of
Socrates. Its ethical teachings were derived from Socrates, recognizing a single
good, which was apparently combined with the
Eleatic doctrine of
Unity. Some of Euclid's successors developed
logic to such an extent that they became a separate school, known as the
Dialectical school. Their work on
modal logic,
logical conditionals, and
propositional logic played an important role in the development of logic in antiquity.