  Several points are worth noting about these commentaries: First, Masters in the Arts faculty were formally forbidden from talking about theological matters in their philosophical commentaries. Notwithstanding this formal prohibition, the commentaries on the categories were crucial for subsequent theological discussions, and the thinnest of pretexts would sometimes occasion a digression into theological territory. Perhaps the most important topic was the definition of an accident and whether or not every accident actually inhered in a substance or only had the potential so to inhere in it. How one answered this question was extremely significant in discussions of the Eucharist, in which the quantity of the host, after consecration, no longer had a substance in which to inhere.  