Bertrand Russel wrote about Aristotle´s distinction between substance (ousía) and universal (kathoulou, in Greek):
«What is signified by a proper name is a "substance", while what is signified by an adjective or class-name, such as "human" or "man" is called a "universal". A substance is a "this", but a universal is a "such" - it indicates the sort of thing, not the actual particular thing. A universal is not a substance, because it is not a "This" ». (Russell, History of Western Philosophy, page 160)
There is a mistake on Russel´s thoughts about Aristotle. "Man" is not an universal but a specie, i.e, a common form of similar objects, in the case, human bodies. In fact, Aristotle never consideres the essence as a universal - for example: the essence horse, the form of all real horses, is not a universal - although he considers sometimes the genus - for example: animal - as a universal. He wrote, refuting the theory of separated Ideas from sensible world of Plato:
« But perhaps the universal, while it cannot be substance in the way in which the essence is so, can be present in this, e.g., animal can be present in man and horse. Then clearly there is a formula of the universal. And it makes no difference even if there is not a formula of everything that is in the substance: for none the less the universal will be the substance of anything. Man is the substance of the individual man in whom is present; therefore the same will happen again, for a substance, e.g., animal, must be the substance of that in which it is present as something peculiar to it. And further it is impossible and absurd that the "this", i.e., the substance, if it consists of parts, should not consist of substances nor of what is a "this", but of quality; for that which is not substance, i.e., the quality, will be then prior to substance and to the "this". Which is impossible; for neither in formula nor in time nor in coming to be can the affections be prior to the substance; for then they would be separable from it. » (Aristotle, Metaphysics, Book VII, 1038b, 15-30, The Complete Works of Aristotle, volume II, Princeton/ Bollingen Series; the bold is put by me)
We must know how to interpret accurately this text . Aristotle is criticizing the theory of Plato who sustained that archethypes - i.e., pure and immaterial forms, such as Man, Tree, and qualities, such as Kindness, Justice- are substances, i.e, individual essences. And he is also criticzing Plato for not prioritizing the archetypes. To Aristotle, on considering a Man with Courage, it is impossible that Courage (a quality) is prior to Man (a essence) because Courage only exist in Men (or in Animals).
On Aristotle, the universal is a quality, nor a form or essence, neither a substance or materialized and individualized form . Animal is a quality, not a form. In fact, animal holds multiple forms different from each other. And the universals as such, above all genera, such as the one and the being, are qualities.
© (Direitos de autor para Francisco Limpo de Faria Queiroz)