genera, or omits all genera, they have no answer except that this is their own stipulation and convention. Yet genuine knowledge clearly does not vary with differing conventions. It has thus become evident that what they have described belongs to the realm of stipulation and convention, although they have presented it as essential realities and knowledge. This is the very essence of going astray and leading others astray. It is like someone taking two identical individuals and declaring one a believer and the other a disbeliever, one knowledgeable and the other ignorant, one blessed and the other wretched—not because of any difference between the two themselves, but merely by his own stipulation and convention. Thus, despite their claim to use rational inference, they distinguish between like things and equate unlike things.

(Eighth:

Their requirement to state the distinguishing differentiae, while maintaining their distinction between the essential and the accidental, is impossible to fulfil. For any distinguishing attribute that is among the properties of the thing defined and is coextensive with it can be treated by someone else as an accidental attribute inseparable from its essence.

(Ninth:

Their account involves circularity and is therefore invalid.

They say:

“The thing defined cannot be conceived unless its essential attributes are stated.”

Then they say:

“An essential attribute is one that must be conceived in order for the essence to be conceived.”

Thus, if the learner cannot conceive the thing defined until he conceives its essential attributes, and cannot know that an attribute is essential until he conceives the subject possessing it—which is the thing defined—and cannot conceive that subject until he conceives its essential attributes and distinguishes them from other attributes, then knowledge of the essence depends on knowledge of