 As to the second sort of unity concerning the number of highest categories, those who are pluralists about the number of categories still may (or may not) posit one highest category—a summum genus, such as entity or being—under which all the entities in the lower categories fall. Spinoza (Ethics IV pref., II: 207), for instance, is a pluralist about the categories but a monist about the highest categories, positing a categorical divide between substance and mode but unifying both under being: 