metaphysics of definition: problems of definition in Zeta and Eta of Aristotle's Metaphysics

The aim of this article is to reconstruct the problems and answers which Aristotle raises in Zeta and eta of Metaphysics. Aristotle’s fundamental presupposition here is that definition has parts, and it corresponds to essence or form. This very presupposition leads to the main problems raised in Zeta and Eta. These problems are ordered at each other, and answering one leads to other. According to this articles reconstruction, Aristotle encounters to four main problems on compounds, unity of definition, matter as part of definition, and universality of definition. If definition should to have parts, parts also need to have some unity. then, what guarantees this having parts and yet having some unity? Aristotle’s answer is matter. now, Aristotle encounters with the problem of justification of matter’s entering into definition, because matter is unintelligible. For answering this difficulty, matter should have considered universalized and indeterminate, and this, in turn, leads to last problem, namely, the problem of universality of definition.