Abstract
It is not certain when or by whom S0009838800011642_inline1 and S0009838800011642_inline2 were first technically distinguished as genus and species. The distinction does not appear in Plato's extant writings, whereas Aristotle seems to take it for granted in the Topics, which is usually regarded as among his earliest treatises. In his dialogues Plato seems able to use S0009838800011642_inline3 interchangeably to denote any group or division in a diairesis, including the group that is to be divided