Catachrestic Plural Forms. Gregory of Nyssa and Theodore Abū Qurrah on Naming and Counting Essences

The fourth-century thinker and theologian Gregory of Nyssa was a convinced realist about universals. According to him, there is just one substance man for all the individuals of the species man and this universal substance is completely instantiated by each individual. In two of his treatises – the Ad Ablabium and the Ad Graecos – he draws linguistic consequences from this realist position. This enquiry results in the thesis according to which it is incorrect to use natural kind terms in the plural form, because that would involve stating a plurality of substances, when in fact there is just one substance for all the individuals of a given kind. In consequence, since the substance of all individual human beings is the same, the word ‘man’ can only be used adequately in the singular form. In this contribution, Gregory's reasoning is reconstructed. In the second part of the paper, the posterity of his theory and its endorsement by Theodore Abū Qurrah at the turn of the eighth and ninth centuries are examined