as a deity in the
Library of Celsus in
Ephesus. Aristotle discusses the nature of wisdom, or first philosophy, which he defines as the study of first principles and causes.
Books I–VI: Alpha, little Alpha, Beta, Gamma, Delta and Epsilon •
Book I or Alpha begins by discussing the nature of knowledge and compares knowledge gained from the
senses and from
memory, arguing that knowledge is acquired from memory through experience. It then defines "
wisdom" (
sophia) as a knowledge of the
first principles (
arche) or
causes of things. Because those who are wise understand the first principles and causes, they know the
why of things, unlike those who only know
that things are a certain way based on their memory and sensations. The wise are able to teach because they know the
why of things, and so they are better fitted to command, rather than to obey. He then surveys the first principles and causes of previous philosophers, starting with the
material monists of the
Ionian school and continuing up until
Plato. •
Book II or "little alpha": Book II addresses a possible objection to the account of how we understand first principles and thus acquire wisdom, that attempting to discover the first principle would lead to an
infinite series of causes. It argues in response that the idea of an infinite causal series is absurd, and argues that only things that are
created or destroyed require a cause, and that thus there must be a primary cause that is
eternal, an idea he develops later in Book Lambda. •
Book III or Beta lists the main problems or puzzles (
aporia) of philosophy. •
Book IV or Gamma: Chapters 2 and 3 argue for its status as a subject in its own right. The rest is a defense of (a) what we now call the
principle of contradiction, the principle that it is not possible for the same proposition to be (the case) and not to be (the case), and (b) what we now call the principle of excluded middle: — there cannot be an intermediary between contradictory statements. •
Book V or Delta ("philosophical lexicon") is a list of definitions of about thirty key terms such as
cause,
nature,
one, and
many. •
Book VI or Epsilon has two main concerns. The first concern is the hierarchy of the sciences: productive, practical or theoretical. Aristotle considers theoretical sciences superior because they study beings for their own sake—for example, Physics studies beings that can be moved—and do not have a target (
telos, "end, goal"; , "complete, perfect") beyond themselves. He argues that the study of being being, or First Philosophy, is superior to all the other theoretical sciences because it is concerned with the
ultimate causes of
all reality, not just the secondary causes of a part of reality. The second concern of Epsilon is the study of "
accidents" (), those attributes that do not depend on
(τέχνη) or exist by necessity, which Aristotle believes do not deserve to be studied as a science.
Books VII–IX: Zeta, Eta, and Theta Books Zeta, Eta, and Theta are generally considered the core of the
Metaphysics. Book Zeta (VII) begins by stating that "being" has several senses, the purpose of philosophy is to understand the primary kind of being, called
substance (
ousia) and determine what substances there are, a concept that Aristotle develops in the
Categories. Zeta goes on to consider four candidates for substance: (i) the '
essence' or 'what it is to be' of a thing (ii) the universal, (iii) the
genus to which a substance belongs and (iv) the material
substrate that underlies all the properties of a thing. • He dismisses the idea that matter can be substance, for if we eliminate everything that is a property from what can have the property, such as
matter and the shape, we are left with something that has no properties at all. Such 'ultimate matter' cannot be substance. Separability and 'this-ness' are fundamental to our concept of substance. • Aristotle then describes his theory that
essence is the criterion of substantiality. The essence of something is what is included in a ('according to itself') account of a thing, i.e. which tells what a thing is by its very nature. You are not musical by your very nature. But you are a human by your very nature. Your essence is what is mentioned in the definition of you. • Aristotle then considers, and dismisses, the idea that substance is the universal or the genus, criticizing the Platonic
theory of Ideas. • Aristotle argues that if genus and
species are individual things, then different species of the same genus contain the genus as individual thing, which leads to absurdities. Moreover, individuals are incapable of definition. Finally, he concludes book Zeta by arguing that substance is really a cause. Book Eta consists of a summary of what has been said so far (i.e., in Book Zeta) about substance, and adds a few further details regarding difference and unity. Book Theta sets out to define
potentiality and actuality. Chapters 1–5 discuss potentiality, the potential of something to change: potentiality is "a principle of change in another thing or in the thing itself qua other." In chapter 6 Aristotle turns to actuality. We can only know actuality through observation or "analogy;" thus "as that which builds is to that which is capable of building, so is that which is awake to that which is asleep...or that which is separated from matter to matter itself". Actuality is the completed state of something that had the potential to be completed. The relationship between actuality and potentiality can be thought of as the relationship between form and matter, but with the added aspect of time. Actuality and potentiality are distinctions that occur over time (
diachronic), whereas form and matter are distinctions that can be made at fixed points in time (
synchronic). Finally, chapters 7–9 discuss the interaction of potentiality and actuality with their respective object's subject/substrate. Chapter 10 is primarily about
logic.
Books X–XIV: Iota, Kappa, Lambda, Mu, and Nu •
Book X or Iota: Discussion of unity, one and many, sameness and difference (
contrariety), and diversity/differences within species via the lens of contrarieties. •
Book XI or Kappa: Briefer versions of other chapters and of parts of the
Physics. •
Book XII or Lambda: Further remarks on beings in general, first principles, and God or gods. This book includes Aristotle's famous description of the
unmoved mover, "the most divine of things observed by us", as "the thinking of thinking". •
Books XIII and XIV, or Mu and Nu:
Philosophy of mathematics, in particular how numbers exist. == Legacy ==