 It must be admitted, that Aristotle’s list of the species in quality is at first blush a bit odd. For instance, why should we consider any of the species listed as falling directly under quality? Indeed, when Aristotle lists the species, he does not follow his usual procedure and provide the differentiae that distinguish them. If there are such differentiae, we should expect that habits and dispositions, for instance, can be defined as such and such a quality. The same would of course be true for the other qualities. But not only does Aristotle not provide these differentiae, but it is also difficult to see what they might be. To appreciate the difficulty, one need only ask: what differentia can be added to quality so as to define shape?