a response to the paradox of knowledge of the substance in ibn sina’s al-ta‘liqat

in al-ta‘liqat–which is most likely a collection of avicenna’s lectures– it is intended to answer to a paradox concerning the knowledge of the substance. this paradox can be reconstructed this way: if, by knowing something, its quiddity comes to mind, then with knowing a substance its quiddity–which is a substance–comes to mind. conversely, according to peripatetic philosophy, knowledge is a quality in the soul and an accident. in this way, a paradox rises which says our knowledge of substance must be substance and accident–and not substance – at the same time. al-ta‘liqat’s response to this paradox is that what is substance is the concept of substance which is the concept of “not being in subject”; and what is accident is our knowledge of substance which is a quality in the soul. therefore, the subjects in the two apparently paradoxical statements are not identical but in one of them the subject is the concept of substance and in the other one the subject is the mental existence of substance. from here, it is clear that the response mulla sadra– using the concepts of primary essential and common technical predications– presents to this paradox and similar paradoxes like those of absolute nonexistent and individual and universal can be found in avicenna’s books.