Enneads VI.1: Of the Ten Aristotelian and Four Stoic Categories
Shape Is Not a Quality; but Specific Appearance, or Reason
What could be said of the shape of every thing? If we speak of the shape as far as something has a specific form, that has no regard to quality; if it be spoken of in respect to beauty or ugliness, together with the form of the subject, we there have a reason.
ARISTOTLE WAS WRONG IN CALLING “ROUGH,” “UNITED,” “RARE,” AND “DENSE” QUALITIES.
As to rough, united, rare and dense these could not be called qualities; for they do not consist only in a relative separation or reapproximation of the parts of a body, and do not proceed everywhere from the inequality or equality of position; if they did, they might be regarded as qualities. Lightness and weight, also, could be correctly classified, if carefully studied. In any case, lightness is only a verbal similarity (a “homonym”) unless it be understood to mean diminution of weight. In this same class might also be found leanness and slimness, which form a class different from the four preceding ideas.