A more serious point for consideration is the fact, generally admitted by scholastics,(223) that one and the same real accident may belong to different categories if we regard it from different standpoints. _Actio_ and _passio_ are one and the same _motus_ or change, regarded in relation to the agent and to the effect, respectively. _Place_, in regard to the located body belongs to the category _ubi_, whereabouts; in regard to the locating body it is an aspect of the latter’s _quantity_. _Relation_, as we shall see, is probably not an entity really distinct from its foundation—quality, quantity, or causality. The reason alleged for this partial absence of real distinction between the Aristotelian categories is that they were thought out primarily from a logical point of view—that of predication.(224) And the reason is a satisfactory one, for real distinction is not necessary for diversity of predication. Then, where they are not really distinct entities these categories are at least aspects so fundamentally distinct and mutually irreducible that each of them is indeed a _summum genus_ immediately under the concept of being in general. It seems a bold claim to make for any scheme of categories, that it exhausts all the known modes of reality. We often experience objects of thought which seem at first sight incapable of reduction to any of Aristotle’s _suprema genera_. But more mature reflection will always enable us to find a place for them. In order that any extrinsic denomination of a substance constitute a category distinct from those enumerated, it must affect the substance _in some real_ way distinct from any of those nine; and it must moreover _be not a mere complex or aggregate_ of two or more of the latter. Hence denominations which objects derive from the fact that they are terms of mental activities which are really immanent, _actiones_ “_intentionales_,”—denominations such as “being known,” “being loved,”—neither belong to the category of “_passio_” proper, nor do they constitute any distinct category. They are _entia rationis_, logical relations. Again, while efficient causation resolves itself into the categories of _actio_ and _passio_, the causation of final, formal and material causes cannot be referred to these categories, but neither does it constitute any new category. The influence of a final cause consists in nothing more than its being a good which is the term of appetite or desire. The causation of the formal cause consists in its formally constituting the effect: it is always either a substantial or an accidental form, and so must be referred to the categories of substance, or quality, or quantity. Similarly material causality consists in this that the matter is a partial constitutive principle of the composite being; and it therefore refers us to the category of substance. It may be noted, too, that the ontological principles of a composite being—such as