Abstract

It is not certain when or by whomandwere first technically distinguished asgenusandspecies. The distinction does not appear in Plato's extant writings, whereas Aristotle seems to take it for granted in theTopics, which is usually regarded as among his earliest treatises. In his dialogues Plato seems able to useinterchangeably to denote any group or division in a diairesis, including the group that is to be divided.