فصل: الثالث: الفصل، وهو كلي مقول على الشيء في جواب «أي شيء هو في ذاته؟»
The third predicable is differentia: a universal predicated in answer to 'What kind of thing is it in its essence?'
Differentia is an essential determination that distinguishes a species from other species under the same genus. Rational (nāṭiq) serves as the differentia of the human species. It indicates rational capacity, not merely audible speech.