The subject of an Aristotelian science is investigated with a view to identifying its per se attributes, that is, its necessary but non-constitutive properties. The subject of geometry is spatial magnitude and its species (such as triangle); finding, for example, that “internal angles summing to two right angles” belongs to “triangle” is the proper task of the science of geometry. If the subject matter of logic is secondary intelligibles, then the proper task of logic will be identifying the per se attributes of secondary intelligibles. According to Khûnajî, however, some of the properties investigated by the logician are attributes of primary intelligibles; in consequence, the subject matter of logic must be something more general than secondary intelligibles.  This prompted Khûnajî to declare that conceptions and assents are the subject matter of logic. Kâtibî accepted this line of reasoning: