Beginning with Aristotle?
A. W. Stetz
June 23, 1999
Both the terms physics and metaphysics were introduced into the En-
glish language through the writing of Aristotle. If the works bearing these
titles had not survived, it is doubtful whether either ?eld of study would
have the form and content that it has today. It would certainly be known
by some other name. We might even construct a slightly ?ippant de?nition
of metaphysics; it is the study of those topics discussed in Aristotle’s Meta-
physics. (It would be stretching the point to de?ne physics in the same way,
but certainly the topics in Aristotle’s Physics are a valid part of modern
physics.) This, if no other reason, makes the study of Aristotle useful and
interesting. There is another, more subtle, value in studying the works of a
thinker who is so remote from us in time as well as philosophical outlook.
The study of physics is replete with abstract concepts such as space, time,
force, ?eld, causality, etc. which seem natural to us only because we have
grown up with them. Try, for example, to de?ne time. (We will return to
this topic in a later chapter.) Well, time is what you measure with clocks.
And what is a clock? A clock is an instrument that beats out equal intervals
of time. Suddenly time, that cornerstone concept of physics, seems to be
based on a circular de?nition. One way to escape such circular arguments
is to step back away from your intellectual milieu and study how thinkers in
other eras have addressed the same issue. We will have occasion to do this
throughout this book. Let’s start with Aristotle.
Aristotle was born in 384 BC in a small town in northern Greece. He moved
to Athens when he was still a teenager and became part of the intellectual
circle that centered around Plato.
He stayed in Athens until the death
of Plato in 347 and then moved to Atarneus on the coast of Asia Minor.
?Copyright 2000 from Life, the Universe and Everything, Albert W. Stetz
Eventually (343) he was invited to the court of Philip II, King of Macedon,
at Mieza to tutor his son, Alexander. This Alexander, or course, we know
as Alexander the Great, perhaps the most powerful man in antiquity. It is
fascinating to speculate what these two remarkable men might have had to
say to one another. Unfortunately, no historical record of their interactions
In 335 Aristotle returned to Athens.
The Academy that Plato had
founded was still ?ourishing, but Aristotle preferred to set up his own school
in the public Lyceum. There he taught and presumably composed most of
the works that have come down to us. He left Athens in 322 and died
a year later in Chalcis, on the island of Euboea, where his mother’s fam-
ily had estates. The Lyceum continued in Athens under the leadership of
Theophrastus to whom Aristotle in his will bequeathed his school.
There is an ancient biography of Aristotle contained in Lives of the
Philosophers by Diogenes Laertius. In it is a list of books attributed to
Aristotle. There are some 550 books listed, which have been estimated to
be equivalent to six thousand pages of modern text. The range of subjects
is astonishing: art, rhetoric, biology, psychology, ethics, government, and
physics are all represented, but this list does not begin to cover the range of
Only a fraction of these works have survived, some thirty in all. The most
complete English edition of his works, the revised version of the “Oxford
translation,” 1 contains 2383 pages including some spurious texts. Nonethe-
less, these surviving works seem to cover all of Aristotle’s main philosophical
interests. To a modern reader these books often seem maddeningly obscure,
pedantic, and full of embarrassing ga?es and fantasies. In the ?rst category
is the famous passage in which he argues that women are really inferior and
incompletely developed men! His writing on biology is full of strange things.
He for example remarks that the Lybian ostrich has eyelashes and cloven
hooves!2 Despite all this, his work has an intellectual energy and range of
interests that may be unprecedented in western civilization. Even in our
century he has continued to challenge and stimulate some of the brightest
scholars in philosophy.
We think of Aristotle as a philosopher; he would probably have called
himself a scientist. The word “science” after all, comes from the Greek word
for knowledge, and Aristotle’s business was the acquisition of knowledge. He
divided science into three categories: theoretical sciences, practical sciences,
1The Complete works of Aristotle ed. Jonathan Barnes, Princeton, 1984
2Parts of Animals
and productive sciences. The goal of productive sciences is to produce ob-
jects. These sciences include poetics and rhetoric, obviously, since their goal
is produce poems and speeches. Practical sciences, such as ethics and pol-
itics, are concerned with the performance of actions. We will be primarily
concerned with the theoretical sciences whose goal is the discovery of truths.
The theoretical sciences are further subdivided into mathematical, nat-
ural, and theological sciences. Mathematical science included arithmetic
and geometry. Although Euclid (whose dates are a bit uncertain) probably
wrote the Elements around 300 BC shortly after Aristotle’s death, Aristotle
was familiar with the sort of reasoning that we associate with “Euclidean
geometry.” In this branch of mathematics one starts with what seem like un-
questionable truths such as “parallel lines are everywhere equidistant,” and
then derives from them a series of theorems using purely deductive reason-
ing. Aristotle, who claimed to have invented the study of formal logic, was
very much impressed with this, and he seems to have regarded geometry as
a model for all the sciences. To the extent that one can discern a “scienti?c
method” in his works, it is this: start with what seem like unquestionable
truths supposedly based on a careful observation of the real world, and then
reason deductively from premise to conclusion.
Theology, according to Aristotle, is the study of changeless things. We
will have more to say about this when we discuss the Metaphysics. This
leaves the natural sciences such as physics, astronomy, chemistry, meteo-
rology, botany, zoology, and psychology. As I observed before, the bredth
of interest is remarkable. He contributed to all these ?elds and in a sense,
de?ned them for future study.
With that introduction in mind, let’s take a closer look at Aristotle’s
The word “physics,” comes from the Greek word phusis. This is usually
translated as “nature,” but not nature in the sense that we usually use the
word. Aristotle might say that phusis is the internal activity that makes
anything what it is. Our word for nature comes from Latin roots having to
do with birth and growth, and these associations are present in the Greek
word as well. It is in the “nature” of a human embryo to develop into a fetus,
to be born, and eventually to become a mature human being. This is the
internal activity that makes it what it is. One of Aristotle’s most in?uential
books is entitled simply Phusis, or as it is always translated, Physics. It
deals primarily with motion, and by extension, space, time, and causality,
concepts that are still central to physics today. In a closely related book, On
the Heavens, Aristotle applies his theory of motion to the stars and planets.
Together they dominated physics and astronomy until the time of Galileo.
Aristotle begins his discussion of physics by identifying four kinds of
For what changes always changes either in thinghood, or in
amount, or in quality, or in place· · ·3
Physics is concerned with motion, but motion has a more general meaning
than we usually give it. It can mean change of place, which we are accus-
tomed to treating quantitatively, as well as changes in “thinghood,” which
could not possibly admit to any sort of quantitative reasoning. By treating
all four kinds of motion on the same footing Aristotle makes quantitative
What other kinds of reasoning are there? In the Posterior Analytics
Aristotle argues that scienti?c reasoning should have the form of a syllogism.
(A familiar example of a syllogism is “All men are mortal, Socrates is a man,
therefore Socrates is mortal.”) The premises should be self-evident, and
the conclusion should have some explanatory value. Presumably Aristotle
was thinking about geometry. The basic axioms seem self-evident, and the
reasoning probably could be cast in syllogistic form (although this is not
how it is usually presented).
With the bene?t of two thousand years of hindsight, however, we can see
that Greek geometry is a dangerous model on which to base one’s scienti?c
method. Consider the axioms of Euclidean geometry. Is it true, for example,
that parallel lines never meet? So long as “parallel lines” refers to something
in the mathematical imagination, then the words “true” and “false” hardly
have any meaning. I have simply used the property “never meet” as part of
my de?nition of an abstract entity called “parallel lines.” If, on the other
hand, “parallel lines” refers to real physical lines (such as lines drawn on a
surface or the paths of light beams in empty space), it is by no means clear
that they never meet. Lines of longitude drawn on a sphere are parallel
in some sense, but they meet at the poles. One consequence of Einstein’s
general theory of relativity is that the three dimensional space of the universe
can, at least in principle, have this same property as the two dimensional
surface of a sphere. We say colloquially that “space is curved.” (Whether
space on the scale of the universe is actually curved is still not entirely clear.
3Physics, Book III, Chapter 1
It is certainly true that it has this property in the vicinity of very massive
objects.) When it is applied to the real physical world the “self-evident”
nature of parallel lines becomes entangled with matters of de?nition, (What
do you mean by a straight line? How do you de?ne “parallel”?) as well as
very subtle questions of fact (What is the structure of space?) that could
not even have been asked before the development of di?erential geometry in
the nineteenth century.
At any rate, Aristotle’s Physics does not have the orderly structure of
self-evident postulates followed by syllogistic deductions. The structure has
rather been called “aporetic” from the Greek word “Aporia” meaning “puz-
zle” or “di?culty.”4 Aristotle repeatedly presents a contradiction or, as it
is often translated, an “impasse,” and then reasons around it. The most
important of these contradictions came from the philosopher Zeno of Elea,
(490?-430 B.C.), who devised four famous paradoxes, all purporting to prove
that there is no such thing as motion. The Physics is in part an extended
answer to these paradoxes.
Zeno argues, for example, that an arrow shot into the air does not, in
fact, move. If you look at the arrow “now,” it is “here.” True, the arrow
may be somewhere else at a later time, but the moment of perception is now,
and now the arrow is stationary. Today, of course, we resolve this paradox
by resorting to the notions of continuity that are the basis of di?erential
calculus. Aristotle resolves the di?culty by inventing an non-quantatative
(or at least non-algebraic) formulation of continuity. He argues that time
must be in?nitely subdividable; between the present instant and any subse-
quent instant there must be an in?nite number of “nows.” This de?nition
of continuity was rediscovered in the nineteenth century by the German
mathematician Richard Dedekind. That Aristotle could have invented this
without any exposure to what we would call mathematical analysis is very
Unfortunately, there are many things in the Physics that seem either
strange or factually wrong. He claims, for example, that there can be no
such thing as an empty void, that an isolated point cannot move, that all
motion (in the sense of change-of-place) is either in a straight line or a
circle with circular motion restricted to the heavenly bodies and straight
line motion restricted to earthly things. He claims that an object tossed in
the air becomes stationary before changing direction and that a projectile,
such as a javelin, moves after it leaves the thrower’s hand only because it is
4cf. Jonathan Barnes’s essay “Life and Work,” in The Cambridge Companion to Aris-
totle, ed. J. Barnes, Cambridge University Press 1995
pushed along by the air.
I should mention in connection with these claims that Aristotle’s repu-
tation has had a curious history in the intellectual history of western civ-
ilization. Sometime after the fall of the Roman empire his works were re-
discovered by scholars and theologians associated with the Roman Catholic
Church, translated into Latin, and studied intently for centuries. His work
was regarded by some as second only to the Holy Scriptures in authority
regarding higher truths.
In the renaissance, however, particularly start-
ing with the sixteenth century, he fell from grace with the intellectuals.
It became, and still is, fashionable to ridicule him for being authoritarian,
pedantic, obscure, and wrong! Bertrand Russell is probably writing for most
experts of our time in the following quote from his monumental History of
His doctrine on this point (the theory of substances and univer-
sals), as on many others, is a common-sense prejudice pedanti-
Aristotle’s metaphysics, roughly speaking, may be described as
Plato diluted by common sense. He is di?cult because Plato
and common sense do not mix easily.
I cannot be so glib. Aristotle so vastly excells the philosophers of his
own time and, even by Russell’s admission, the next two thousand years
that he deserves to be taken seriously. Let us rather try to understand what
attitudes or missteps may have resulted in these strange conclusions. It
seems to me that there are at least three.
• Motion should be treated quantatatively and algebraically. This is
seen especially clearly in the argument that a point cannot move. In
Book VI, Chapter 2, Aristotle discusses what we would call speed or
velocity. In modern notation, v = ?x/?t, where ?x is the distance
traveled by the point in some very short interval of time ?t.
cannot say this, however, because Physics lacks the concept of space
as we understand it mathematically. We would say that the particle
moves from x1 to x2 in time ?t = t2 ? t1, so that ?x = x2 ? x1. The
idea of assigning a variable to describe position is foreign to Aristotle’s
way of thinking. As a consequence the reasoning in this section is very
5Bertrand Russell, A History of Western Philosophy, Simon and Schuster, Inc., 1959
labored and obscure. When he comes around to the motion of a point
in Chapter 10 of the same book, he says in e?ect that v = ?x/?t,
but ?x is the size of the point. That is zero of course, so v = 0 as
well. Put this way the error is immediately obvious, but without a
quantatative notion of space it is extremely obscure.
• Despite his remarks about the logical structure of scienti?c arguments
in the Posterior Analytics, Aristotle does not use syllogysms in the
Physics but rather another kind of argument that can best be called
the process of elimination. In response to a question or “impass” he
will formulate three (or more) explanations, say A, B, and C. A and
B can be ruled out with some simple arguments, and so, it is claimed,
the correct answer is C. This is a treacherous argument, because it is
usually impossible to prove that A, B, and C are the only possibilities.
Perhaps the right answer is Z, which cannot even be formulated with
the language and concepts at hand.
• Aristotle’s de?nition of motion is di?cult to make sense of. I will
quote at length from Sachs’s translation6 of the crucial passage from
Book III, Chapter 2.
Therefore, motion is the being-at-work-staying-itself of the
movable, and happens to it by contact with what is moving,
so that the latter too is acted upon. And what moves will
always bear a form, whether a this or an of-this-kind or a
this much, which will be the source and cause of its motion
whenever it moves.
The elaborate hyphenated noun, being-at-work-staying-itself, is Sach’s
attempt to translate entelecheia, a word that Aristotle has invented by
combining and punning on several di?erent words. In his commentary
on this passage the translator makes the strange remark that this word
has been misunderstood by “almost everybody” for the last thousand
years. (I certainly don’t understand it!) The point is that science
is, ?rst of all, a community enterprise. A useful scienti?c idea must
be understandable to all the practitioners in the ?eld, and it must be
possible to reformulate it in many ways without losing it’s content.
A concept that has proved incomprehensible to a thousand years of
serious scholarship hardly ?ts into that category.
6Joe Sachs, Aristotle’s Physics; A Guided Study, Rutgers University Press, 1995
Any reader in the late twentieth century who visits a second-hand book
store is likely to ?nd a shelf marked “Metaphysics.” He or she will ?nd
therein a strange farrago of topics: pyramid power, astrology, tarot cards,
palmistry, and spiritual self-levitation; topics that survive for purposes of
entertainment and perhaps exploitation in an age of gullibility. The chain of
association that leads from that branch of philosophy called “metaphysics”
to these book store curiosities is a long and tortured one. I do not care to
trace it out.
The origin of the word “metaphysics” is also problematic. Every mod-
ern list of the works of Aristotle indicates that he wrote something called
Metaphysics despite the fact that the word was unknown in his time. It
originated with a later editor named Andronicus of Rhodes, one of the later
masters of the Lyceum that Aristotle founded, who compiled a collection
of essays and called it ta meta ta phusika, “what comes after the Physics.”
The phrase was eventually transliterated into Latin and then into English
as “metaphysics.” Scholars have since disputed what Andronicus meant
by “comes after.” Did he mean that it comes after the Physics in some
manuscript collection or perhaps “comes after” in some (unspeci?ed) logical
or philosophical sense? We don’t know. Scholars also dispute whether the
material collected in the Metaphysics is really one topic or several. I will
return to that issue below.
Most modern translations of the Metaphysics are full of words like “sub-
stance” and “accident” and “essense,” common English words that are used
to mean something much di?erent from their primary dictionary de?nition.
These words are in fact a legacy of medieval Latin scholarship. Take for
example one of Aristotle’s favorite words, ousia. The common meaning had
something to do with inherited wealth or estate, that which cannot be taken
away from the one who is born with it. It is also related to the participle
of the verb “to be.” For Aristotle it refers to an entire complex of things
that are not easy to pin down. It is way of being that is primary in the
sense that it belongs to things that have attributes but which are them-
selves not attributes of anything. Joseph Owens in The Doctrine of Being
in the Aristotelian ‘Metaphysics,’ devotes an entire chapter to the ques-
tion of how it should be translated into English and eventually decides on
“entity.” Joe Sachs, in the translation already alluded to, comes up with
“thinghood.” The standard translation is “substance,” a transliteration of
the Latin word, substantio. It has often been argued that by using the Latin
terms we are buying into medieval Latin scholarship with all its prejudices
and errors. Choices like “thinghood” and “entity” are intended to circum-
vent this. I would argue that “thinghood,” “entity,” and “substance” are
equally acceptable if we remember that they are only place holders for the
phrase, “what Aristotle meant by ousia” and that much of the discussion in
and about the Metaphysics is really about the meaning of words.
The Metaphysics as it has come down to us consists of fourteen “books”
of varying length labeled with the Greek letters A, ?, B, ?, ?, E, Z, H, ?,I,
K, ?, M, and N. These symbols are pronounced (and often written) Alpha,
“Little Alpha,” Beta, Gamma, Epsilon, Zeta, Eta, Theta, Iota, Kappa,
Lambda, Mu and Nu respectively. Alpha is an introduction beginning with
the famously quotable line,
All men by their very nature feel the urge to know.7
Aristotle describes Wisdom as the study of “?rst principles” or “?rst causes.”
(What we call metaphysics he usually called “?rst philosophy.”) The book
concludes with a historical survey together with some criticism of Plato’s
theory of Ideals. Little Alpha is an alternative introduction with some com-
ments about philosophical methodology. Book Beta is a list of metaphysical
problems, some of which are discussed in subsequent chapters. Gamma looks
like another introduction in which Aristotle explains that metaphysics (or
?rst philosophy) is the study of “being qua being.” Delta is composed of
thirty short chapters each de?ning a philosophical term. Epsilon is another
short book in which Aristotle reiterates that “We are seeking the principles
and causes of existing things.”
Aristotle gets down to hard work in the next three books (Z, H, ?),
which deal with substance, potency and actuality. They appear to be the
heart of the Metaphysics. They are extremely di?cult reading due to the
unfamiliarity of the language and the obscurity of the argument. The sub-
sequent book Iota discusses the notions of unity and plurality. Kappa is a
summary of Gamma, Delta, Epsilon, and part of the Physics. It is believed
to be spurious, i.e. not written by Aristotle. It is certainly more intellegible
than the books it summarizes.
The book Lambda contains Aristotle’s theology. It develops his theory
of the Eternal Prime Mover, the Supreme Intellect, and the nature and op-
eration of good in the world. Books Mu and Nu, which are closely related,
discuss the philosophy of mathematics with special reference to Plato’s the-
ory of Ideals.
This is a very super?cial summary of the material in the Metaphysics.
It is well to remember that it is a collection put together by a later editor.
7Aristotle’s Metaphysics trans. by John Warrington, J. M. Dent & Sons, 1956
There is certainly no program or unifying principle that one can discern
by reading through it.
In fact, we do not even know for what purpose
the documents were originally intended. Often they have the “feel” of a
man thinking out loud. Scholars like to make a distinction between exoteric
books, those written for a general audience, and esoteric books written for a
special group of insiders. Plato’s Dialogs are certainly exoteric in this sense.
The Metaphysics is esoteric, and we are not among the insiders!
What then is the Metaphysics about? At the beginning of Gamma we
There is a science which investigates being qua being and its
essential attributes. This science di?ers from all the so-called
special sciences in that none of the latter deals generally with
being as such. They isolate one part of it and study the essential
attributes of that one part, as do, for example, the mathematical
Translators often render the phrase, “being qua being,” as “beings qua be-
ing.” The point is that even though the subject is singular in Greek, it really
refers to “things that exist,” i.e. “beings.” The purpose of ?rst philosophy
is not to study statues or bronze spheres or beds (Aristotle’s favorite ex-
amples) for the attributes that make them di?erent from one another, but
rather to study the things they all share by virtue of the fact that they exist.
This program immediately encounters a di?culty, however, that to us
seems purely verbal; the word “exist” means di?erent things in di?erent
contexts. Take compound nouns, for example. Does a ?ock of sheep exist in
the same way that a single sheep exists? What about things that are parts
of some larger whole; does a ?nger exist in the same way as the body of
which it is a part? Qualities present additional problems as do the things of
mathematics. Does “hardness” exist? What about beauty, numbers, right
triangles, etc.? Aristotle’s approach to this problem is to argue that all uses
of “exist” point back to some one primary meaning of the word. A ?ock
of sheep, for example, exists in a way that is secondary to the existence of
individual sheep. To put it in a silly way, there can be sheep without ?ocks,
but there can’t be ?ocks of sheep without sheep. That which exist in this
primary way Aristotle calls “substance” (or ousia as described above).
The ancient and everlasting question ‘What is being?’ really
amounts to ‘What is substance?’ · · · it must be our ?rst and
principal, if not our only subject.