Aristotle’s Metaphysics is divided into fourteen books, which are usually named after the first thirteen letters of the Greek alphabet. The books, in order, are Alpha, Alpha the Lesser, Beta, Gamma, Delta, Epsilon, Zeta, Eta, Theta, Iota, Kappa, Lambda, Mu, and Nu. Though all fourteen books treat certain common themes, many of them are independent of all the others. Scholars believe that the Metaphysics is really a compilation of a number of Aristotle’s writings that later editors grouped together. Some of the material in the Metaphysics repeats that covered in the Physics.


Knowledge consists of particular truths that we learn through experience and the general truths of art and science. Wisdom consists in understanding the most general truths of all, which are the fundamental principles and causes that govern everything. Philosophy provides the deepest understanding of the world and of divinity by pursuing the sense of wonder we feel toward reality.

There are four kinds of cause, or rather kinds of explanation, for how things are: (1) the material cause, which explains what a thing is made of; (2) the formal cause, which explains the form a thing assumes; (3) the efficient cause, which explains the process by which it came into being; and (4) the final cause, which explains the end or purpose it serves. The explanations of earlier philosophers have conformed to these four causes but not as coherently and systematically as Aristotle’s formulation. Aristotle acknowledges that Plato’s Theory of Forms gives a strong account of the formal cause, but it fails to prove that Forms exist and to explain how objects in the physical world participate in Forms.

Book Alpha the Lesser addresses some questions of method. Though we all have a natural aptitude for thinking philosophically, it is very difficult to philosophize well. The particular method of study depends on the subject being studied and the inclinations of the students. The important thing is to have a firm grasp of method before proceeding, whatever the method. The best method is that of mathematics, but this method is not suitable for subjects where the objects of study are prone to change, as in science. Most reasoning involves causal chains, where we investigate a phenomenon by studying its causes, and then the cause of those causes, and so on. This method would be unworkable if there were infinitely long causal chains, but all causal chains are finite, meaning that there must be an uncaused first cause to every chain.

Book Beta consists of a series of fifteen metaphysical puzzles on the nature of first principles, substance, and other fundamental concepts. In each case, Aristotle presents a thesis and a contradicting antithesis, both of which could be taken as answers to the puzzle. Aristotle himself provides no answers to the puzzles but rather takes them as examples of extreme positions between which he will try to mediate throughout the rest of the Metaphysics.

Book Gamma asserts that philosophy, especially metaphysics, is the study of being qua being. That is, while other sciences investigate limited aspects of being, metaphysics investigates being itself. The study of being qua being amounts to the search into first principles and causes. Being itself is primarily identified with the idea of substance, but also with unity, plurality, and a variety of other concepts.