 Auriol maintained that only five of the ten Aristotelian categories actually exist in the extra-mental world (substance, quality, quantity, action, and passion), the other five (relation, place, time, position, and state/habit) being merely conceptual or mind-dependent, i.e. resulting from an intellect conceiving one of the actual categories to be other than it is in extra-mental reality. Thus, the conceptual categories exist only potentially, but not actually, in extra-mental reality; it is possible for the intellect, upon acquaintance with one of the actual categories in extra-mental reality, to form the concept of the corresponding conceptual category (on Auriol’s ideas on the category most broadly, see Amerini 2014). This theory has been studied most thoroughly with regard to Auriol’s ideas concerning the category of relation (cf. e.g., Henninger 1989, pp. 150–73; Brower 2018, sections 3.1 and 3.2; Friedman 2013, pp. 550–56). In this context, Auriol maintains that real relations are conceptual in nature, not existing in extra-mental reality, and hence dependent upon the activity of the mind; the three types of real relation originate from the intellect’s acquaintance with respectively quantity (e.g., a relation of equality), quality (e.g., a relation of similarity), and action and passion (e.g., a relation of causality). Moreover, Auriol, in stark contrast to the medieval tradition before him, thinks of relations as being between two terms, and not in a subject towards a term. While the impact of Auriol’s ideas on the categories has not been studied in any depth, nevertheless it is interesting that Gregory of Rimini devotes a great deal of his discussion of the category of relation to a thorough attack on Auriol’s view (Henninger 1989, p. 173; for Auriol’s more general views on the ontology of accidents as well as some reaction to those views, see Pasnau 2008, Pasnau 2011, pp. 213-220).