DISTINCTION BETWEEN COMPLEMENTS OF BEING, AND QUALITIES.
We may now say that, in the intelligible world, qualities are the characteristic differences in being or essence. These differences effect distinction between the beings; in short, they cause them to be beings. This definition seems reasonable. But it does not suit the qualities below (in the sense-world); some are differences of being, as biped, or quadruped (as thought Aristotle);[330] others are not differences, and on that very account are called qualities. Still, the same thing may appear a difference when it is a complement of the being, and again it may not seem a difference when it is not a complement of the being, but an accident: as, for instance, whiteness is a complement of being in a swan, or in white lead; but in a human being like you, it is only an accident (as thought Aristotle).[331] So long as the whiteness is in the ("seminal) reason," it is a complement of being, and not a quality; if it be on the surface of a being, it is a quality.