 Some of these criteria could be interpreted in a manner such that the universal consisting of individuals falls under the category of true wholes. Consider, for example, criterion (a). The genus Animal is divided by considering what sort (qualis) of animal something is. Human Being is a rational animal, Horse is an irrational animal. In contrast, Human Being is not divided with respect to what sort of human being Socrates is. Socrates and Cicero are both rational animals. The difference between Socrates and Cicero is due to the fact that this bit of matter which makes up Socrates is different from that bit of matter which makes up Cicero. A difference in matter is typically considered to be a quantitative difference. Hence, the parts of the universal whole Human Being appear to be distinguished by quantity rather than quality.