  The name ‘Dialectical school’ is used for a group of philosophers active from the later 4th to the mid 3rd centuries BC who are referred to as members of the Dialectic sect (hairesis) or as dialecticians (dialektikoi) in some later ancient sources (Diogenes Laertius [DL] 1.19). They were traditionally counted among the philosophers of the Megaric school (founded by Euclides of Megara, author of Socratic dialogues ), but may have formed an independent branch of this sect. Together with the Megarics, Cyrenaics and Cynics they count among the minor Socratic schools. Their main philosophical interest was in dialectical skill and accomplishment, including the development and resolution of logical paradoxes. They also made several important positive contributions to the development of propositional logic. It is uncertain whether the members of the Dialectical school were connected by an institution comparable to other ancient philosophical schools, or whether their union under one name in later reports was based more loosely on their common philosophical interest in dialectic.