How philoshophy works

HWPOHOWIRLKOSSOPHY



PHWHOOWIRLKOSSOPHY

THE CONCEPTS visually explained

Consultant editor Marcus Weeks

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CONTRIBUTORS Marcus Weeks (consultant editor) studied Music and
Philosophy at Sheffield University and worked as a teacher, piano
restorer, and trombonist before settling into a career as an author.
He has written and contributed to numerous books on philosophy,
psychology, music, and the arts, including several titles in the
Dorling Kindersley “Big Ideas” series.

Roxana Baiasu has taught philosophy to students from all
around the world at universities including Oxford, Vienna, and
Birmingham. She has published in the areas of European Philosophy,
the philosophy of Ludwig Wittgenstein, feminist philosophy,
and the philosophy of religion.

Robert Fletcher has written on political developments for journals
such as Talking Politics and Politics Review. He has taught at Oxford
University, and he currently specializes in the Philosophy of Mind,
in which he is working toward a PhD.

Andrew Szudek is a writer and editor who studied philosophy at
Cambridge University, where he specialized in Wittgenstein and the
Philosophy of Mind. He has worked on numerous nonfiction titles,
ranging from travel guides to military history.

Marianne Talbot has taught philosophy for the colleges of Oxford
University for 32 years. Her philosophy podcasts have been
downloaded more than 8 million times.

CONTENTS

Introduction 10

FOUNDATIONS

The source of everything 16
Cosmic origins
Sacred geometry 18
All is flux
All is one 20
Zeno’s paradoxes
Elements and forces 22
Immortal seeds
Atomic theory 23
Examining ideas
Platonic realms 24 ANALYTIC
Plato’s allegory of the cave
One world only 26
Form is function 28
An Earth-centered cosmos 30 PHILOSOPHY
Purposes in nature 32
Scholastic philosophy
Transubstantiation 34
Occam’s razor
The scientific revolution 36 What does a word mean? 86
Doubting the world 88
Mind and body 38 Russell’s theory of descriptions 90
The body as a machine 92
The one substance 40 Picturing the world 94
The blank slate 96
An infinity of minds 42 Meaning and observation 98
Facts and ideas 100
Shaping the world 44 Dispensing with metaphysics 102
104
with the mind 46 A private language is impossible 106
Kinds of truth 108
Reality as a process 48 Wittgenstein’s language-games 110
The end of history
Class conflict in history 49 Science and falsification
Useful truths
The value of truth 50 The nature of scientific truth
Ideas as tools
52 Words as actions

54 Scientific revolutions

56 Points of view

58 Feminist epistemology

60

62

64

66
68
70
72
74
76
78
80

CONTINENTAL RIGHT AND
PHILOSOPHY WRONG

Objects in the mind 116 Rules and principles 168

Phenomenology 118 PHILOSOPHY Ethics and the law 170
Time consciousness 120 Free will? 172

What is it like to be human? 122 OF MIND Do we have moral
knowledge?
Life before death 124 174

Freedom and identity 126 Does moral truth exist? 176

The “other” 128 The fact-value distinction 178

Gender identity 130 Dualism 146 Aristotle’s virtue ethics 180

The lived body 132 The limits of language 148 Humean ethics 182

Critical theory 134 Behaviorism 150 Deontology 184

Power plays 136 The mind-brain Utilitarianism 186

Deconstruction 138 identity theory 152 Existentialist ethics 188

Feminist postmodernism 140 Eliminative materialism 154 Animal rights 190

Functionalism 156 Euthanasia 192

Biological naturalism 158 Cloning 194

Panpsychism 160

The nature of the body 162

POLITICAL
PHILOSOPHY

Who should rule? 200 LOGIC 234 250
Justifying absolute rule 202 236 256
Government by the people 204 Rationality 238
Popular sovereignty 206 Recognizing arguments 240
How are property rights Analyzing arguments 242
208 Evaluating arguments 244 Index
justified? 210 Deductive arguments 246
Consent and obligation Inductive arguments 248 Acknowledgments
What rights should 212 Fallacies
214 Formal logic
people enjoy? 216
Kinds of liberty
Should rights be limited? 218
How should we 220

manage change? 222
To work is human nature 224
Making more objective 226
228
political decisions
Perspectivism and politics
A just war?
Women and patriarchy



HOW PHILOSOPHY WORKS 10 11
Introduction

INTRODUCTION

Curiosity has been the driving force behind philosophy since its earliest beginnings
in ancient civilizations. Rather than simply accept the way things are, we humans
have a natural tendency to question the world around us, and our place in it, and
attempt to satisfy our curiosity with rational explanations—to philosophize.

Philosophy emerged from the ponderings of people in the ancient world about the
nature and structure of the universe. This is the branch of philosophy known as
“metaphysics,” and from it, centuries later, the natural sciences were born. However,
philosophers also posed questions that science cannot answer. These were questions
about the nature of existence itself—the field known as “ontology”—and about the
nature and limits of knowledge—the field of “epistemology.” Other, more practical
questions became the subjects of moral and political philosophy: How should we live?
What is good? What is bad? How should we organize society?

These fundamental questions are not only the foundations of philosophy, they are
also the topics of conversation among ordinary people. In this book, you will find
many different theories and suggestions that philosophers have offered in answer
to these questions and their justifications for their views. Some will be familiar
to you, or will agree with your own ideas, which will perhaps give you food for
thought. Chapter 1 traces the history of metaphysics and epistemology from Thales
to Nietzsche—that is, from the 6th century bce until the end of the 19th century.
Chapters 2 and 3 continue the story through the 20th century, focusing on the
parallel developments of analytic and continental philosophy. Chapter 4 examines
the philosophy of mind; Chapters 5 and 6 focus on ethics and political philosophy,
respectively; and the final chapter, Chapter 7, covers logic.

FOUNDATIONS

In the beginning, philosophy was the same as science.
Philosophers looked for natural explanations for the way
things are. Crucially, however, they also asked: How do
we know when our explanations are correct?





14 15FOUNDATIONS
Introduction

FOUNDATIONS

This chapter explores the central questions of “empiricists,” our primary source of knowledge
metaphysics and epistemology, namely “What is is observation. In turn, these theories raise questions
the nature of things that exist?” and “What exactly about the nature of human understanding and
is knowledge?” It examines how philosophers even of thought itself.
have answered these questions historically,
taking the story up to the end of the 19th century. Historically, the rationalist school can be traced
Chapters 2 and 3 complete the story, focusing back to Plato, who argued that our senses are
on the “analytic” and “continental” schools unreliable, but that the truth can be arrived at
of the 20th century. through rational reflection. This idea was revived in
the 17th century by René Descartes, Baruch Spinoza,
The first Greek philosophers asked, “What is and Gottfried Leibniz. Empiricism, on the other
everything made of?”, which is the fundamental hand, can be traced back to Aristotle, who claimed
question of metaphysics. This prompted further that our senses alone can be trusted. In the modern
inquiries into the structure of the cosmos, and also age, this idea was revived by John Locke, George
raised more abstract questions about the nature of Berkeley, and David Hume—Hume even claiming
existence itself—the branch of metaphysics known as that our belief in causation, for example, is unjustified.
ontology. Over the centuries, philosophers have offered For Immanuel Kant, this took skepticism too far. He
many different answers to these questions, inspiring proposed instead that we gain knowledge through
different approaches and schools of thought. Some, perception, but that the world we perceive is already
for example, argued that the universe is made up of a shaped by concepts that we are born with. This
single substance—a view known as “monism”—while synthesis of rationalism and empiricism inspired
others proposed that the universe has two component the idealism of Georg Hegel—a monist who argued
elements—a view known as “dualism.” Similarly, some that history is driven by the evolution of ideas.
regarded the universe to be eternal and immutable,
while others thought that it is constantly changing. Karl Marx, an admirer of Hegel’s, subverted this
idea, arguing that economic conditions rather than
These contrasting views were the subject of ideas are the driving force of history. At the same
philosophical debate, which gave rise to yet more time, Friedrich Nietzsche argued a far more radical
questions: How can we know anything about the idea—that objective truth itself is an illusion. He
world? How do we acquire our knowledge? These claimed that the very idea of “the truth” is a hangover
questions are the topic of epistemology, or the theory from our religious past, and that without it there
of knowledge. According to some philosophers, are simply “perspectives,” or individual points of
known as “rationalists,” knowledge comes primarily view. His claim that “God is dead” left a challenge
from our ability to think; for others, known as for subsequent philosophers: to search for new
foundations or to learn to live without them.

The source
of everything

The origins of Western philosophy lie in the ideas of the so-called
Milesian school, a group of thinkers led by Thales of Miletus
in the Greek province of Ionia (part of present-day Turkey).

Seeking rational explanations Thales eventually concluded that this single
substance must be water. His argument was based on
Thales (c.624–c.546 bce) and the other Ionian observations: water is a vital resource, necessary for all
philosophers—including Anaximander (see pp.18–19) forms of life, and all living things are moist; it is capable
and Anaximenes (c.585–c.528/5 bce)—were the first of changing from liquid to solid to gas, so all matter
thinkers known to have questioned the previously must be water in some stage of transformation; the
accepted mythological explanations of the nature Earth (it seemed at the time) floats on a sea of water;
of the cosmos. Instead, they looked to nature itself, and moist substances become air and earth as they dry
using reason and observation to fathom the natural out. While he is often cited as stating “everything is
world, thus paving the way for future scientific water,” it would be more accurate to say that he held
and philosophical thought. water to be the fundamental source of everything.

Often referred to as the “first philosopher,” Thales “Nothing is more active
was also a celebrated astronomer, engineer, and than thought, for it flies
statesman. His inquiries led him to believe that over the whole universe.”
everything in the world, the whole of nature, is derived
from a single source—what Aristotle later described as Thales of Miletus (6th century bce)
its arche, its fundamental nature or principle. This, he
reasoned, must be a single material substance from
which everything else in the cosmos is derived.

PRACTICAL INQUIRIES The four elements

Gifted with a practical mind, Thales applied intellectual The ancient Greeks believed
rigor to philosophy and geometry. He is credited with that the world was made of four
the discovery that the height of a pyramid can be elements—earth, water, air, and
determined by measuring its shadow. Once a day, fire—to which Aristotle added a fifth,
a person’s shadow is exactly the same length as their the “quintessence” (see p.43). These
height. Thales noted that if a pyramid’s shadow is elements roughly correspond to our
also measured at this critical moment, the modern understanding of the four
height of the pyramid is revealed. states of matter: solid, liquid, gas,
and plasma. For Thales, water was
primary and gave rise to the other
elements. For Anaximenes, the
primary element was air.

FOUNDATIONS 16 17
The source of everything

FIRE
When air is super-heated, it
becomes fire. Flames and
lava have a life that reflects

their watery origins.

EARTH AIR
Earth and earthy things Thales observed that
such as rock are made wet things dry out in the
of condensed water, and sun and concluded that
from this all terrestrial their moisture was

life arises. turning into air.

WATER
Thales believed that the Earth is a
disk floating on water. The shoreline
is where solid ground emerges from
the sea as the water condenses.

Cosmic origins

Anaximander, Thales’ student, developed an innovative theory to
explain the origin and structure of the cosmos. It was radically
different from the ideas of his contemporaries in Miletus.

The Boundless geography and astronomy that helped him to develop a
strikingly original explanation of how everything had
Born in the Greek city of Miletus, Anaximander (c.610– come into being. Like the other early Greek philosophers,
546bce) studied with Thales (see pp.16–17), but also he believed that there is a fundamental underlying
traveled widely, learning from Babylonian and Egyptian principle, an arche, which is the source of everything
scholars. From his travels, he gained a knowledge of

The birth of the cosmos

Anaximander was the first thinker to offer a rational
and comprehensive description of the origin of the
cosmos. Based on observation, he proposed a theory
that explained the behavior of the heavenly bodies,
as well as the natural phenomena of the Earth.

APEIRON

GERM

1 IN THE BEGINNING
A small “germ” separates itself from the apeiron. This
contains all the essential ingredients of the universe, including
the heavenly bodies and the space they inhabit.

HOT RING

VAPOR MOON
COLD

2 THE SEPARATION OF OPPOSITES 3 THE SUN, MOON, AND STARS
Within the “germ” that has separated from As the ball of fire expands, it disintegrates into three
the apeiron, opposing forces, such as hot and
cold and wet and dry, begin to emerge. A cold concentric rings, or “wheels,” with the Earth at their center.
Light shining through holes in these opaque rings is observed as
center forms, surrounded by vapor and an the Sun, the Moon, and the stars. The hole in the “Moon wheel”
expanding sphere of fire.
periodically closes, generating the phases of the Moon.

18 19FOUNDATIONS
Cosmic origins

in the universe. However, he rejected the idea that At the center of these rings is the Earth, which is
this is a specific material substance, such as water drum-shaped, like the hub of a wheel. Anaximander’s
(as Thales believed), and instead suggested the idea most remarkable insight is his conception of space: he
of the apeiron (meaning “the Boundless”), from which realized that the heavenly bodies are not situated on a
everything is derived, and that the universe itself domed vault equidistant from the Earth, but that they
originates from a small part of the apeiron. circle the Earth at different positions in space. Perhaps
even more remarkably, he reasoned that the Earth,
Anaximander describes the process of the birth because of its position at the center of the cosmos, is
of the cosmos as one of the separation of opposites, not supported by water or any other object, but is
especially hot and cold, to form three concentric rings floating freely in space.
of fire, which he likened to the rims of chariot wheels.

EUROPE

LIBYA ASIA

“What is infinite A DRUM-SHAPED EARTH
is something other We live on the flat surface of a cylindrical Earth,
than the elements, floating freely in space. A central sea is surrounded by
and from it the land, which in turn is surrounded by a circular ocean.
elements arise.”
BIOLOGY
Anaximander of Miletus (6th century bce)
Anaximander believed that the Earth
was originally covered with water,
which later dried to form the land due
to the heat of the Sun. The first life
forms were fishlike creatures with
tough, thorny skins. This defensive
covering provided a protective
environment for their more vulnerable
offspring, the first humans, who were
generated to populate the land.

Sacred geometry

Perhaps the best known of the pre-Socratic philosophers, Pythagoras
was a near-mythical figure who established a cultlike community
devoted to the pursuit of science, mathematics, and mysticism.

A cosmos governed by numbers actually thought, since he left no written legacy
and many of the ideas ascribed to him may very well
Pythagoras (c.570–c.495 bce) is remembered as the be those of others. However, it is certain that he
mathematician who gave his name to the theorem set up a community in southern Italy and trained his
of right-angled triangles—that the square of the followers in philosophical and scientific inquiry. The
hypotenuse is equal to the sum of the squares of the “so-called Pythagoreans,” as Aristotle later described
other two sides. However, in his own time, he was them, studied astronomy and geometry and examined
better known for his belief in the transmigration the link between numbers, mathematics, and the
(rebirth) of the soul. Little is known of what he

Sacred numbers A = 1:1

Numbers took on a mystical significance for the Pythagoreans D = 3:4
as they made links between mathematics and the natural E = 2:3
world. The first four integers (whole numbers) were especially
important: 1) the fundamental number associated with
the origin of everything; 2) the material derived from it;
3) the beginning, middle, and end; and 4) the number of the
elements. Together, they add up to 10—the “perfect number.”

12 3 4 A = 1:2
THE OCTAVE
GEOMETRIC OBJECTS Pythagoras also discovered
Pythagoreans revered the number 1, from which they that musical intervals that
believed all numbers derive. For example, geometric figures sound harmonious when
can be created from a single point: connecting two points played together correspond
creates a line; connecting parallel lines forms a square; and to the mathematical ratios
connecting parallel squares creates a cube. of 1:2, 2:3, and 3:4. This
means that if a string sounds
the note A, a string half of its
length will sound the A an
octave higher (an eighth above),
a string two-thirds its length will
sound the note E (a fifth above), and a
string three-quarters its length will sound the
note D (a fourth above). For Pythagoras, it was no
coincidence that these ratios only involve the first four
integers, which add up to the perfect number, 10.

20 21FOUNDATIONS

Sacred geometry

natural world. For example, the Pythagoreans— imposes limits on the Boundless, giving form to the
notably Philolaus—discovered that musical harmony universe. For the Pythagoreans, the cosmos—and
is based on mathematical ratios using the first four everything in it—is governed by numbers, so numbers
whole numbers (see below). have an almost divine significance.

Pythagoras is believed to have learned geometry “The Pythagoreans ...
from Thales (see pp.16–17). However, he was also fancied that the principles
familiar with the cosmological theories of the Milesian of mathematics were the
school, and Anaximander in particular, whose chief principles of all things.”
thesis was that the cosmos is formed from “the
Boundless”—an inexhaustible, unobservable, life- Aristotle, Metaphysics (4th century bce)
giving substance (see pp.18–19). Pythagoras reasoned
that the cosmos must have an underlying structure
determined by the laws of mathematics, which

THE COSMOS JUPI SATUR N
Philolaus, Pythagoras’s student, is credited with TER
the idea that all the heavenly bodies—including the COUNTE
Earth and a “Counter-Earth”—orbit a central fire
called the Hearth. The distances of the stars and THE TETRACTYS
planets from the center correspond to the ratios
of the consonant musical intervals, creating what The tetractys—a triangle composed
the Pythagoreans referred to as the “harmony of 10 dots—had great symbolic
of the spheres.” significance for the Pythagoreans.
Its rows of one, two, three, and
ENUS TH four add up to the perfect
V MARnumber 10, and its central dot
ME R EARTHis comparable to the Hearth
Sat the center of the cosmos.
EAR HEARTH
THE SUN MO
RCUR
ON
Y

All is flux

While other thinkers believed the arche—the fundamental principle
underlying the cosmos—to be an immutable substance, Heraclitus
thought that the universe is governed by perpetual change.

The Logos go, and living things are born and THE SAME RIVER
die. Everything, he concluded, is in
Lying at the heart of Heraclitus’s a state of constant flux. Heraclitus is famously quoted as
cosmology is what he calls the saying that “everything flows,”
Logos—the reason or explanation Heraclitus argued that it is the likening the world to a river. The
for everything that exists. His nature of everything to be in a waters of a river are constantly
definition of the Logos is somewhat process of change, and that this shifting, so a person can never
cryptic, but it can be seen as change is caused by a war that go into the same river twice.
something like the laws of nature exists in all things. Everything is However, the river is also a single,
or physics that we now know made of two contrary properties unchanging entity: if its waters
govern the universe. and is characterized by both; stop flowing, the river becomes a
however, over time, one of those lake or dries up completely.
Heraclitus (c.535–c.475bce) properties becomes dominant,
made a radical departure from the upsetting the former balance.
thinking of his contemporaries by Life and death, for example, are
viewing what governs the cosmos in constant strife, but also depend
not in terms of a substance, but on each other. Heraclitus saw
instead as an ongoing process of fire as a symbol of the Logos—
change. He observed that over time, always changing, yet remaining
nothing remains the same: day uniquely itself.
becomes night, seasons come and

Constant war L
O
Heraclitus stated that all things come G
into being in accordance with the Logos O
and consist of conflicting, opposite S
properties. Light and dark, life and
death, hot and cold are constantly
fighting for dominance. However,
just as a path on a mountain is
both the path up and the path
down, opposites are not
inherently harmful—indeed,
their tension sustains the
world. For this reason,
Heraclitus claimed that
“War is the father
of all things.”

All is one 22 23

Taking up a position diametrically opposed to the views of
Heraclitus, Parmenides argued that the change we perceive in the
world is an illusion, and that reality is eternal and unchanging.

The illusion of change been, and will always be. Strictly impermanent. Parmenides says that
speaking, nothing can be said this is due to the deceptive nature
Unlike Heraclitus, Parmenides to be unlike anything else. of our senses, and that only reason
(c.515–c.445bce) based his ideas can reveal the true nature of things:
on logic alone as opposed to In contrast to this rational account a single, changeless reality in which
observation. Consequently, his of reality, the world as we perceive “all is one.”
inquiries were less concerned it seems ever-changing and
with what the universe is made
of than the nature of being itself. The way of truth

First, he claims that a thing either In his philosophical poem On Nature, Parmenides describes the world as we
is or is not: it either does or does perceive it as the “way of opinion”—that is, the way we interpret the changes we
not exist. Second, he argues it see in the world. The “way of truth,” however, explains how the changes we see
cannot be said that nothing—a are illusions: reality is an unchanging, timeless, singular entity.
void—exists, for only a thing can
exist. Third, he says that since I CANNOT HAVE MOVED THERE HERE
there is no such thing as nothing, I must always have been
it is impossible for something either where I am, since motion,
to come from nothing or to be being change, is
reduced to nothing. From this, it impossible.
follows that change is impossible,
for change can only ever be a I CANNOT HAVE BEEN I CANNOT I CANNOT BE UNLIKE
particular thing (such as a seed) I must always have NOT BE OTHER THINGS
becoming nothing as it turns into
something else (a plant)—but been as I am, since the Difference is impossible,
nothing can be reduced to nothing. past cannot have so nothing can be
What is, then, must always have been different. unlike anything else.

NEED TO KNOW

❯❯Parmenides is sometimes called THEN NOW ME IT
the “father” of ontology (the study
of the nature of being, existence, ALL THAT IS, IS
and reality). ONE, UNCHANGING
What exists is one, and
❯❯The idea of two worlds—one
of illusion and one of reality and indivisible, like
truth—had a significant influence a perfect sphere.
on Plato (see pp.36–37).

❯❯The view that existence is a
singular, unchanging entity is
known as Parmenidean monism.

Zeno’s paradoxes

As a student of Parmenides, Zeno of Elea believed that all forms of
change are illusory. To prove it, he devised a series of arguments
that apparently demonstrate the impossibility of motion.

An unchanging reality gives a step-by-step account of a race in which a
fast runner can never catch up to a slower one,
Like his mentor Parmenides, Zeno of Elea (c.490– thereby ridiculing conventional ideas of speed and
430 bce) was a pioneer of the use of logical arguments motion (see right).
to justify ideas, even when these flew in the face of
how things appear to us (see p.23). The Parmenidean A third paradox concerns the flight of an arrow and
notion of an unchanging, eternal reality, for example, cleverly demonstrates that it is never actually moving. If
contradicts the evidence of our senses, but Zeno set we accept that an instant is a moment in time with no
out to show that the changes that seem to occur in duration, then at any given instant, Zeno argues, the
the world are logically impossible and nothing but
an illusion. He did this by presenting a number 1 A HEAD START
of paradoxes—logical arguments that lead to At the beginning of the race, the
apparently absurd conclusions. tortoise starts from a position some
distance ahead of Achilles. As the tortoise
The most famous of Zeno’s paradoxes are those slowly moves away from its starting point,
that concern motion, which he regarded as a specific Achilles rushes to catch up with it.
kind of change—that of an object’s position from
one place to another. In the dichotomy paradox, he Achilles and the tortoise
shows how a simple walk covering a finite distance
can become an impossibly infinite task, involving Probably Zeno’s best-known paradox tells of the race
the completion of countless stages (see below). between the athletic warrior Achilles and a tortoise.
In the paradox of Achilles and the tortoise, he To make the race fair, Achilles gives the tortoise a
head start. Common sense suggests that Achilles will
THE DICHOTOMY at some point overtake the tortoise, but Zeno succeeds
in reasonably arguing that Achilles can do no more
In order to walk a certain distance, a person must first than narrow the gap between them.
walk half of that distance. But before reaching that
halfway point, they must get a quarter of the way, and
before that an eighth, and so on without end. Walking
any distance at all will therefore entail an infinite
number of shorter stages, involving an infinite number
of tasks, which will take an infinite amount of time to
complete. The same is true for anything that apparently
moves, proving that movement is in fact impossible.

1/16 1/8 1/4 1/2 1

24 25FOUNDATIONS

Zeno’s paradoxes

flying arrow is in its present location and nowhere else. NEED TO KNOW
It occupies a static position in the air and is motionless.
Time, he says, progresses through an infinite number ❯❯A paradox uses apparently sound logic to reach a
of instants: if the arrow is motionless at every instant, conclusion that common sense suggests is ridiculous
it is never moving. Motion is therefore impossible, so or contradictory.
our experience of motion must be an illusion.
❯❯A fallacy is an error of reasoning, such as an invalid
Zeno’s logic is apparently impeccable, and it is logical argument (see pp.246–47). Paradoxes are
difficult to find any flaw in his arguments. Modern fallacies in which the flaws are difficult to identify.
mathematical techniques, such as the calculus,
have been used to resolve his paradoxes, but not to ❯❯Zeno’s paradoxes are examples of reductio ad
everyone’s satisfaction. The philosopher Bertrand absurdum reasoning that show the weaknesses
Russell considered the paradoxes “immeasurably subtle of opposing arguments.
and profound,” and Zeno a mathematical genius.

“These writings of mine were
meant to protect the arguments
of Parmenides against those
who make fun of him.”

Zeno of Elea (5th century bce)

2 NARROWING THE GAP
By the time Achilles has reached the
point where the tortoise began, the tortoise
has moved on, so Achilles still has some
distance to make up to draw level with it.
The tortoise thus continues the next stage
of the race with a head start, albeit a
shorter one than before.

3 STUCK IN SECOND PLACE
When Achilles gets to the point that the
tortoise had previously reached, the tortoise has
again advanced to a position beyond it. At every
stage in the race, Achilles can only reach the
point where the tortoise has been, by which
time the tortoise has moved farther along.

Elements and forces

In contrast to Parmenides’s static view of the cosmos, Empedocles
proposed a theory of a dynamic system composed of four elements
driven by the forces of attraction and separation.

Cosmic building blocks Empedocles described these elements as the
“building blocks” of the cosmos, from which all matter
Although he accepted Parmenides’s assertion that is formed. The various material substances are made
nothing comes from nothing, and that nothing can from combinations of these elements in different
be destroyed, Empedocles (c.490–c.430bce) was proportions. But, unlike the elements, the substances
uncomfortable with the idea of a singular and formed from them are not unchangeable.
unchanging world (see p.23). The world as he saw it is
marked by plurality and change. To reconcile the two In this way, Empedocles explains that change in the
ideas, he proposed a theory based on the four elements world is not an illusion: the elements can separate as
(or “roots,” as he called them) that were identified by substances disintegrate and recombine in different
early philosophers: earth, water, air, and fire. These, proportions to form new substances. He believed that
he argued, are each immutable and eternal, satisfying there is a constant process of change and that the
the notion that nothing can be created or destroyed. cosmos is a dynamic system characterized by the

Love and Strife

Empedocles suggests that the changing nature of the cosmos is driven by two opposing cosmic forces: Love
and Strife. Love is the creative force of attraction, which causes the elements to combine in various forms. Strife
is the destructive force of repulsion, which separates the elements from one another and therefore lies behind
the decay of matter. The elements themselves are neither created nor destroyed, but constantly rearranged.

TH AI TH AI
FIR EAR R TER
FIR EARR TER
E WA E WA
LOVE STRIFE

The force of attraction, Love brings together Material things are not permanent, but
the elements in various proportions and undergo a process of decay in which Strife,
the force of repulsion, separates the elements.
combinations to create the different material These elements can then reform in different
objects in the universe. The element of fire
combinations to make other things.
is what gives certain things life.

FOUNDATIONS 26 27
Elements and forces

continual separation and combination of the four formation of matter and even living things govern the
elements. To account for the behavior of the elements, ways in which the elements combine and disintegrate.
Empedocles took an idea from Heraclitus: the action of The continual change inherent in the cosmos therefore
opposing forces (see p.22). He argues that the cosmic results from the fluctuation in the balance or dominance
forces of attraction and separation that underlie the of these opposing forces over time.

Cosmic cycle

The forces of Love and Strife are locked in a battle for dominance, creating an eternal cosmic cycle. When Love
completely overcomes Strife, the elements cannot be separated from one another to form the various substances of
the cosmos. In conflict with Strife, the elements separate and matter and life can be created. However, when Strife
prevails, all that was created dissolves into separate elements, until the influence of Love brings them together again.

LOVE LOVE DOMINATES
The elements become too close

and life is impossible.

LOVE LOVE VS
INCREASES
The elements . STRIFE STRIFE
are brought STRIFE INCREASES
together and The elements are
life is created. separated by
Strife and life is
VS. LOVE STRIFE born again.

STRIFE DOMINATES ORGANS LIMBS UNVIABLE VIABLE
The elements are BEING BEING
separated and life
is destroyed.

THE ORIGIN OF SPECIES
In Empedocles’s version of the birth of the cosmos,
he describes a rudimentary form of natural selection.
The species originated as separate organs that were
brought together by the force of Love in various
combinations, forming all kinds of strange creatures.
However, those assembled wrongly were unable
to breed, and only the “correct” species survived.

Immortal seeds

In his novel theory of the cosmos, Anaxagoras suggested that, as it
derives from a single original substance, everything in the physical
universe contains a portion of everything else.

Everything in everything The “mass” from which the cosmos began was at
some point prompted to start spinning. This motion
Like most philosophers of his time, Anaxagoras acted like a centrifuge, separating the particles and
(c.510–c.428bce) accepted Parmenides’s arguments arranging them into different substances. Each
for the eternal nature of the universe (see p.23), but separate substance, like the unity it derives from, is
argued that there could also be change and diversity. a mixture of these infinitely small primary particles.
According to Anaxagoras, the cosmos originates from While one particular type of seed might predominate
a “mass” or unity consisting of inextricably linked to give the substance its distinct characteristics,
particles that are eternal and indestructible. These every physical thing also contains seeds of every
are the “seeds” of all physical matter, but in this different type of matter. And so everything contains
primordial state they are indistinguishable from one a portion of everything else.
another and have not yet assumed distinct forms.

The cosmic mind Controlling force Nous
The nous, or mind, both
According to Anaxagoras, the primordial, unified initiates the revolution at the
mass of all substances was set into motion by origin of the cosmos and
nous, the cosmic mind, the fundamental force and shapes the way things grow.
governing principle of the universe. As well
as initiating the birth of the cosmos, nous
determines the way that the “seeds” of
physical substances are arranged to
form distinct entities.

INANIMATE THE “SEEDS” OF HUMANS
OBJECTS EVERYTHING

Varied materials form PLANTS
From the mass of minute
particles, the spiraling motion
separates material substances
from the air and ether and spins
out solid and liquid elements.

28 29FOUNDATIONS
Immortal seeds

INFINITELY DIVISIBLE NEED TO KNOW

According to Anaxagoras, SUBSTANCE STAYS THE SAME ❯❯ The Greek word nous in
each and every thing is If the separate pieces of something are Anaxagoras’s writings is often
characterized by the substantially the same, then, regardless of their translated as “mind,” but it also
proportion of the size, they remain the same substance, even means “reason” or “thought.”
substances that it when divided into infinitesimally small pieces.
contains. When divided ❯❯Anaxagoras is credited with
in two, the proportion bringing philosophy to Athens in
of substances remains around 460bce, and inspiring
the same in each half; Socrates, Plato, and Aristotle.
the halves themselves
can also be divided ❯❯In later life, Anaxagoras left
repeatedly, and each Athens for his own safety.
piece will still have the According to some accounts, his
same consistency. unorthodox views led to him
being charged with impiety.

“The seed of everything
is in everything else.”

Anaxagoras (5th century bce)

FOOD BECOMES FLESH

ANIMALS From foliage to fur Portions of substances
A goat eats nothing but For Anaxagoras, the leaves
The nature of food leaves, which contain no that the goat eats contain
Anaxagoras noted that visible traces of muscle, muscle, bone, and fur, albeit
animals often feed on bone, or fur. However, in minute quantities. The goat
substances that bear no the goat’s muscles, bones, stays healthy if it regularly
resemblance to the animals and fur are constantly eats these minute quantities
themselves. The leaves that a replenished by the leaves. of muscle, bone, and fur.
goat eats, for example, bear
no resemblance to the goat.

Atomic theory

In the 5th century bce, the philosopher Leucippus and his pupil
Democritus proposed the revolutionary notion that everything
is composed of indestructible particles moving in empty space.

Atoms and empty space

Like many other philosophers, the Atomists—as they
were later known—attempted to explain the reality of
motion and change. Parmenides had said that these are
mere illusions, since motion requires the existence of a
void, which he deemed a logical impossibility (see p.23).

Atomists turned this argument on its head, however,
suggesting that since motion is patently possible,
the void must exist, and matter must be free to move
within it. Because the movement of matter takes place
at a microscopic level, it is not visible. Matter is
formed of minute particles that Leucippus called
“atoms,” which exist in empty space, and the changes
that can be observed in the cosmos are due to the
motion of these atoms in the void. Each atom is an
eternal and unchanging entity, both indestructible
and indivisible, but capable of joining with others
to form different substances and objects.

Where Parmenides posited eternal, immutable unity,
the Atomists proposed an infinite diversity of eternal
particles that gives rise to an ever-changing cosmos.

Building blocks V OID NEED TO KNOW

According to the Atomists, the atom ATOM ❯❯The void described by the
is the basic unit of every material Atomists is more than empty
substance. These building blocks Indivisible atoms space—it is an absolute absence
of matter are constantly in motion in An object such as a tree of matter, akin to a vacuum.
the void and react with each other, can be divided into its
being either mutually repelled or constituent parts, and the ❯❯The word “atom” comes from
attracted. There are countless kinds parts cut into pieces. But the Greek atomon, meaning
of atoms that join together in these parts are not infinitely “uncuttable” or “indivisible.”
different combinations to form the divisible—at a fundamental
huge variety of substances. They then level, the atoms themselves
separate as those substances decay.
The atoms themselves are immortal are indestructible.
and remain intact. They continue
their movement through the void,
continually and ceaselessly combining,
separating, and reforming.

30 31FOUNDATIONS
Atomic theory

KINDS OF ATOMS

Democritus suggested that atoms come in a range of sizes and shapes, their properties determining the
characteristics of different substances. He proposed that the atoms of liquids are smooth and can move freely
past one another, while solids have more rigid atoms that move less and can connect with other atoms.

AIR WATER IRON SALT
Air atoms are light and The smooth, round atoms Atoms of iron have hooks The taste of salt is caused
wispy, and move freely of water give it its flowing, that interlock to give the by its jagged atoms acting

and independently. liquid character. metal its solidity. on the tongue.

“Nothing exists
except atoms and
empty space;
everything else
is opinion.”

Democritus (5th century bce)

Object Image Sensation Psyche
All objects emanate These image particles, An image makes an The psyche (soul) is
“image particles” of impression on the made of “fire atoms,”
themselves, which which Democritus atoms of the sense which interpret the
called “idols,” travel sensations received
enable them to through the air in organs, creating
be perceived. a sensation. by the senses.
all directions.

Examining ideas

Socrates was a familiar sight in the marketplace in Athens, where
he would engage citizens and students in philosophical discussion,
challenging their preconceived ideas in his pursuit of knowledge.

The dialectic out any inconsistencies or contradictions in it, asking
for an elaboration of the answer to account for them.
Socrates (469–399 bce) left no written record of his This method gradually highlights any assumptions
ideas and famously declared that all he knew for and preconceptions, uncovering the deeper meaning
certain was that he knew nothing. Much of what is of the topic and taking it back to first principles.
known of his thinking comes from his student Plato,
who wrote a series of texts featuring Socrates as the Socrates then sifts out opinions and arguments
protagonist, extracting and analyzing ideas in a that can be refuted, leaving only that which he
masterful way. It is his method of eliciting and knows to be true. From this, he uses the dialectic
examining an argument—elenchus in Greek, meaning to construct a better-informed argument. Although
cross-examination or inquiry—that earned him his such discussions often end without reaching a
place as one of the foremost Athenian philosophers. conclusive answer, Socrates’ key contributions were
to provide a new way of examining existence, and
According to Plato, Socrates described himself as extending philosophy to include morality and justice,
a sort of intellectual “midwife,” helping to give birth not just the physical world.
to ideas. His method was simple, using a process
of question and answer known as “the dialectic”— “An unexamined life
a dialogue between opposing views—that digs is not worth living.”
gradually deeper into the topic of discussion.The
opening question is often a deceptively simple one, Socrates (5th century bce)
in which Socrates typically asks for a definition of
a concept, such as “What is courage?” or “What
is virtue?” He then examines the answer, pointing

SOCRATES’ LEGACY Socratic irony

As well as pioneering the dialectic, Socrates distinguished According to legend, Socrates began a
between knowledge that is gained through reflection campaign of inquiry after he learned that
and knowledge that is gained via the senses. Although the oracle at Delphi had pronounced
he placed little emphasis on the distinction, it was one him the wisest man in the world. Socrates
that his successors developed into the rival schools of set out to prove the oracle wrong but
rationalism and empiricism. discovered that most people in fact knew
less than he did. Socrates feigned ignorance
An early form of rationalism was held by Socrates’ of a subject in order to start his discussions,
most famous student, Plato, who believed that our but as he pointed out the inconsistencies
experience of the world is deceptive and that true in the replies, it became apparent that he
knowledge can be gained through rational reflection knew more than he admitted. Claiming
alone (see pp.34–37). Plato’s own most brilliant student, ignorance to elicit a response in this way has
Aristotle (see pp.38–45), argued the opposite idea—that since become known as “Socratic irony.”
knowledge is arrived at by observation only. The latter
idea became the central tenet of empiricism. In modern
times, rationalism was revived by René Descartes (see
pp.52–55), and empiricism by John Locke (see pp.60–61).

32 33FOUNDATIONS
Examining ideas

3

And is courage an
admirable quality?

2 4

The capacity Yes, very
to endure? admirable.

1 5

What is courage? What about
foolish endurance,

like obstinacy?
Would that be

admirable?

6

No, it wouldn’t.

7

So endurance with foolishness
is not courage because it is not
admirable. So courage is not just
the capacity to endure. It must be

coupled with good sense.

Platonic realms

At the heart of Plato’s philosophy is the notion that the world we live
in is deceptive and that our senses cannot be trusted. Indeed, for Plato,
our world is merely a shadow cast by a higher realm of the Forms.

A world of Forms of a circle. We can do this, he argued, because we
have an idea in our minds of what a circle is—what
Plato, like many philosophers before and since, was an he called the “Idea” or “Form” of a circle—and unlike
accomplished mathematician and was fascinated by the particular instances of circular things, this Form
geometry. He observed that there are many instances is an ideal circle, with no imperfections. Indeed,
of things that are, for example, circular in the world everything we experience—from horses to acts
around us, and that we recognize them as instances
HORSE
CIRCLE

FORMS 360°

APPLE CRO OUNG DRAFT
WL Y
WN OLD

PARTICULARS
BO

Forms and particulars Material objects
There are many kinds of horses, but
According to Plato, only imperfect, particular things exist all are recognizably horses because
in our world. The ideal circle, for example, exists only in they conform to the ideal Form of
the world of the Forms. The Forms are like blueprints a horse. All our ideas of “horsiness”
from which particular things are made. are derived from the ideal Form.

34 35FOUNDATIONS
Platonic realms

of justice—are particular things that we recognize BEAUTY THE GOOD
by comparing them to their relative Forms in our
minds. Moreover, Plato claimed that since we cannot TRUTH
perceive these Forms, they must exist in a realm
beyond our senses—one that we recognize with our 2+2=4
psyche, or intellect. This process of recognition is
largely instinctual, but Plato argued that philosophers
are needed to comprehend certain Forms. Indeed,
for Plato, philosophers ought to be kings: they
should organize society and advise on ethical
matters (see pp.200–201).

JUSTICE

MAGN A CARTA U.S. CON STITUTION
NURE MBERG TRIALS
“If particulars are to
have meaning, there
must be universals.”

Plato (4th century bce)

Abstract concepts DUALISM BODY MIND
There are also Forms of abstract
concepts, such as truth, beauty, and In Plato’s dualistic universe,
virtue. Instances of justice in the earthly the two worlds he describes
realm, for example, are reflections of are perceived in different
the ideal Form of the concept of justice. ways. The earthly realm is
experienced by our bodily
senses; the ideal realm is
understood by the psyche—
our mind or intellect.

Plato’s allegory
of the cave

In the Republic, Plato presented an allegory to show how
our knowledge of reality is restricted by the deceptive
information provided by our senses.

A world of shadows Because the prisoners can only see the shadows,
this is the only reality of which they are aware. They
Plato asks us to imagine a cave in which some prisoners know nothing of the objects casting the shadows and
are held captive. They are shackled to face the back wall would not believe it if they were told about them. They
of the cave and are unable to turn their heads. Their field are literally being kept in the dark about the true nature
of view is restricted to the wall in front of them, across of the world that they inhabit. The point that Plato
which they can see images moving. is making is that our own perception of the world is
similarly restricted, and that the things we believe
The captives are unaware that behind them, hidden to be real are merely “shadows” of the things that
by a low wall, another group of people are parading a exist in the ideal realm of the Forms (see pp.34–35).
variety of objects in front of a fire. It is the shadows of
these objects that the prisoners can see in front of them.

Escaping the cave 2 ILLUSORY IMAGES
The prisoners see images of things on the wall,
Suppose that a prisoner in the cave which, as they have experience of nothing else, they
is freed from her chains. As she looks assume to be reality. What they cannot know, because
behind her, she would be dazzled by they cannot turn around to see it, is that these are only
the light of the fire, but would slowly the shadows cast by other objects.
make out the objects whose shadows
she had mistaken for reality. She
might then be persuaded to leave
the cave and, after initially being
blinded by the sunlight, she would
see that there is more to reality than
the world inside the cave. However,
if she returned to the cave, she would
find it difficult to convince the other
captives of her discovery that their
reality is an illusion.

1 RESTRICTED EXPERIENCE
All that the prisoners can see,
and have ever seen, is the back wall
of the cave. What they view there
is the limit of their experience
of the world.

FOUNDATIONS 36 37
Plato’s allegory of the cave

6 A SUPERIOR WORLD
The world she
discovers is reality. For
“Earthly knowledge Plato, the philosopher’s
is but a shadow.” role is to encourage people
to leave the cave—that is, to
Plato (4th century bce) comprehend the limits of
their experience.

5 EMERGING FROM THE DARK
If the prisoner is led out of the
cave, once her eyes are accustomed
to the sunlight, she sees things that
she never knew existed.

4 SEEING THE LIGHT
At first she is dazzled by
the light of the fire, but then
observes the objects and how
they are responsible for casting
the shadows.

3 REALIZING THE DECEPTION INNATE KNOWLEDGE
A freed prisoner can see behind
her and realize that she has been Plato believed that our
deceived: there is more to the world knowledge of the Forms is
than the images projected onto the wall. something we are born with, FORMS
not something we acquire
through experience. Rather,
we use our reason to access
the Forms, in whose realm we
lived before we were born.
For Plato, philosophers are
like midwives: their role is
to bring to light what we
innately already know.

One world only

Plato’s most brilliant student, Aristotle, did not agree with his
mentor’s theory of Forms. Instead, he proposed that we learn
about the world through experience alone.

Empiricism qualities (such as redness) exist, things, and then generalize about
he did not believe that they do so them, having seen what they
Aristotle could not accept the in a separate dimension. Rather, he have in common. For Aristotle,
idea of a separate world of ideal said, they exist in each particular we gather information about the
Forms (see pp.34–37). Plato had instance in this world. world through our senses and
argued that the Forms—the make sense of it by using our
qualities of being circular, good, For example, the idea of a “circle” intellect or reason. In this way,
or just, for instance—exist in a is general: we have in our minds an we build up ideas, apply labels
separate realm. Aristotle believed idea of what constitutes a perfect to them, and make distinctions.
that there is only one cosmos, circle. He explains that this is not As a philosophical stance, this
which we learn about through because we have innate knowledge is known as “empiricism,” as
our experience of it. Although of the perfect (Form of a) circle, but opposed to Plato’s “rationalism.”
he accepted that “universal” because we experience circular

Using experience

Aristotle argued that we learn
general concepts by experiencing
particular instances: our idea of a
cat is built from our experiences of
many different cats. We use reason
to grasp the general idea “Cat.”

1 UNSCRIBED TABLET 2 OBJECTS
According to Aristotle, we have The knowledge we obtain about
no innate knowledge. When we are
born, our minds are like “unscribed the world comes from our senses. For
example, we gather information about
tablets” waiting to be written on. We the instances of various objects we see
build up our knowledge by learning
from our experiences. with our eyes, which is then transmitted
to our minds.

38 39FOUNDATIONS
One world only

ESSENTIAL AND ACCIDENTAL PROPERTIES NEED TO KNOW

Aristotle argued that all things have two ACCIDENTAL PROPERTIES ❯❯Epistemology is the branch
kinds of properties. An essential property is COLOR SHAPE WEIGHT of philosophy concerned with
what makes a thing what it is. Its other knowledge and the way in
properties are “accidental” properties. ESSENTIAL PROPERTY which we acquire it.

❯❯An apple’s accidental properties ❯❯Inductive reasoning is the
include its color, shape, and weight. logical process of making a
It is an apple whether it is green or red, general rule from a number
round or oval, large or small. of particular instances.

❯❯The apple’s essential property is the ❯❯Empirical knowledge is
substance that it is made from. knowledge that is acquired
by observation or experience
❯❯The essential property of a ball, rather than through reasoning.
however, is its shape; the substance it
is made of is an accidental property.

“Sun”

“Tree”

“Cat”

3 IDEAS 4 NAMES
By using this information from our We then attach labels to these ideas,
giving names to the forms in our minds.
senses, we can form ideas in our minds. In this way, we learn to recognize things
For instance, from our daily experience of
the Sun, we build an idea of the form of the by their characteristics and to distinguish
between different things.
Sun and its defining characteristics.

Form is function

Aristotle argued that to understand a thing is to know four things
about it: what it is made of, how it came into being, its design,
and what function it performs.

Matter and form that there are purposes in nature, NEED TO KNOW
favoring what Aristotle called
In their efforts to understand the “efficient causes” only (see below). ❯❯Aristotle’s four causes are not
nature of things, the pre-Socratic causes in the modern sense, but
philosophers focused on the “stuff” For Aristotle, clay can be used to explanations or reasons for things
that things are made of—the make bricks, crockery, drainpipes, coming into being. For Aristotle,
matter of the cosmos. and even statues. All of these all things have a purpose and are
share the same matter, but each fully known by understanding
Aristotle, however, noted that has its own form. The form of a their four causes (see pp.44–45).
there is more to a thing than its statue, for instance, is different
physical make-up. For him, to know from that of a bowl because the ❯❯“Form” in Aristotle’s ontology
a thing is not only to know what it function of a bowl (to contain food) refers to what makes a thing
is made of, but also what processes is different from that of a statue (to specifically what it is—its essence—
brought it into being, what shape honor a person). However, even and is different from Plato’s idea
(or design) it takes, and what unformed clay has a function, and of a perfect Form on which a
purpose it serves. Aristotle called that is to become those various thing is modeled (see pp.34–35).
these the “four causes,” and argued forms. For Aristotle, matter
that we only understand a thing without form cannot exist. What ❯❯Aristotle’s idea that a substance
when we know its four causes. he calls “prime” matter is pure is a combination of matter and
This radically departed from the potential: it has yet to unfold into form is known as “hylomorphism.”
teachings of the Atomists, for the various forms it can take.
example, who rejected the notion

The four causes 1 MATERIAL CAUSE 2 FORMAL CAUSE
The material cause of a thing The formal cause of a thing is its
Aristotle explained the nature of a
thing in terms of its physical make-up,
its design, the circumstances that
brought it into being, and its purpose
or function. Together, these four
causes tell us all we need to know
about a thing and go far beyond the
Atomists’ claim that a cause is simply a
physical event that brings a thing into
being (see pp.30–31). The Atomists’
view came back into vogue with
Galileo, who saw “efficient causes” as
the only causes relevant to modern
science (see pp.50–51).

is the matter from which it is made. physical design. The formal cause of a
In the case of a sculpture, the sculpture is the blueprint prepared
material cause is a slab of stone. by its maker.

40 41FOUNDATIONS
Form is function

THE SUBSTANCE OF THINGS

According to Aristotle, the substance of a thing—that which makes it what it
is—is more than simply the material from which it is made. All sorts of things
can be made from clay, and it is the form of the clay that makes it, for example,
a bowl. The substance of a thing is therefore its matter and its form. Later
philosophers argued that because the substance of a thing underlies its physical
nature, transubstantiation is also possible (see p.48).

=+

Substance Matter Form
The substance of a bowl is The matter of the bowl The form of the bowl is
what makes it what it is—a its shape, which enables
vessel for containing food. is the material from
which it is made—clay. it to contain food.

“The aim of art is to represent not
the outward appearance of things,
but their inward significance.”

Aristotle, Poetics (4th century bce)

3 EFFICIENT CAUSE 4 FINAL CAUSE
The efficient cause of a thing The final cause of a thing is
is the physical process that brings the purpose for which it has come into
it into being. The efficient cause of being. A statue of Aristotle, for example,
a sculpture is its sculptor. serves to honor the man it depicts.

An Earth- FIRE R
centered cosmos AIR RTH
WATE
Aristotle’s concept of a cosmos with the Earth at its EA
center, surrounded by heavenly spheres, was the
model for astronomy for almost 1,900 years.

The Earth and the heavens

Aristotle believed that the Earth and the heavens are distinct
regions, with a boundary between them marked by the orbit of
the Moon. In the terrestrial, or sublunary, region, the matter from
which everything is made consists of the four elements: earth,
water, air, and fire. According to Aristotle, these elements have a
tendency to move up or down, seeking their natural place of rest.
The earth element tends to move downward, toward the center
of the Earth; water is inclined to settle on the Earth’s surface; above
that floats the air; and finally, there is fire, which rises to the top.

The heavenly spheres

In line with his contemporaries, Aristotle believed that the circle was
the perfect geometric figure. For this reason, he naturally thought
that the heavenly bodies beyond the Moon moved in circular orbits.
This model of a perfect, eternal, geocentric cosmos was accepted for
almost all subsequent astronomical thought until Nicolaus Copernicus
championed the idea of a heliocentric universe in 1543 (see pp.49–51).

KINDS OF SOULS VEGETATIVE SENSITIVE RATIONAL
Plants have only a vegetative Animals have sensitive souls. Unique to living beings,
According to Aristotle, soul with the ability to grow humans have rational souls,
everything consists of both They can move and which can think and reason.
matter and form. The matter and reproduce. experience sensations.
of living things is made up of
the elements, but their form
is the psyche, or soul, which
gives them life. Different
kinds of souls determine
the natures of plants,
animals, and humans.

FOUNDATIONS 42 43
An Earth-centered cosmos

The geocentric universe

Outside the orbit of the Moon lies the celestial region in which the
Sun, the planets, and the stars move in orbits at various distances
from the Earth. Unlike the sublunary region, the celestial region is
made from an incorruptible substance, which Aristotle calls the
“quintessence,” or fifth element. According to Aristotle, the natural
movement of the earthly elements is up or down, toward or away
from the center of the Earth. By contrast, the natural movement
of things in the celestial region is circular. What’s more, earthly
elements tend toward a position of rest, while celestial movement
is unceasing. Thus, Aristotle reasoned that the stationary Earth,
although imperfect, is at the center of the cosmos.

Beyond the Moon’s orbit, Aristotle identified 55 concentric spheres
to which the celestial objects are attached. As they radiate away
from the Earth, the outer spheres draw closer toward perfection,
stretching into spiritual realms that have no material existence. The
universe, for Aristotle, is a perfect form and cannot have come into
being at any one time: it is eternal, unchanging.

THE COMPOUND BEINGS

MOON For Aristotle, everything in the terrestrial region is a combination
of the four elements in varying proportions, giving beings their
distinctive characteristics. The natural tendency of the elements to
seek an appropriate level exerts an upward or downward force:
rooting plants to the Earth or giving animals their mobility.

=

TREE EARTH WATER AIR FIRE
FIRE
THE =
SUN
CAT EARTH WATER
AIR

Purposes in nature

According to Aristotle, everything that exists has a final cause
or purpose—what in Greek is called a telos. In other words,
everything in nature exists to fulfill a goal.

Teleology order to achieve its own ends—its things. Rain does not fall in order
internal purpose. For example, a to water the plants; rather, the
Explaining things in terms of their seed’s purpose is to germinate and plants use the moisture that
purposes was not unusual among become a plant, and trees exist in happens to have been provided
classical Greek philosophers, but order to produce fruit. by the rainfall.
today it stands at odds with our
modern, scientific understanding For Aristotle, it is not only living 1 EFFICIENT CAUSE
of the world (see pp.50–51). To our things that exist for a purpose. Rain The efficient cause in this
modern eyes, it is pretty normal to falls in order to moisten the ground example is the woman who
describe a man-made object, such and enable plants to grow. It is the pushes the rock. The rock
as a tool, in terms of its function or rain’s telos to water the earth and moves because of her actions.
purpose. A hammer, for example, the plants’ telos to grow. Their
exists for the purpose of pounding purpose or goal is the reason they
in nails. But this is an extrinsic have come into being.
purpose, one that is imposed upon
it from the outside. What Aristotle More in line with our modern
proposed was that everything, thinking is the Atomists’ assertion
including everything in the natural that natural things do not have an
world, has an intrinsic purpose: intrinsic purpose or “final cause”
that is, each thing exists in (see pp.30–31): instead, their
existence is the cause of other

THE UNFOLDING WORLD Causation

For Aristotle, the essential property of a seed is its Aristotle’s theory of causation is
ability to grow. That is also its intrinsic purpose: it exists based on his idea that everything
to become a plant, which, in turn, exists in order to has four causes (see pp.40–41). What
produce seeds. Living things are therefore characterized we usually think of as a cause—that
by their tendency to move or change and to reproduce. which makes a thing happen—is what
And, because all terrestrial things are imperfect Aristotle calls an “efficient cause.” For
and impermanent, beings not only grow, example, a person who pushes a rock
but also eventually perish and decay. downhill is the efficient cause of the
rock’s movement. The purpose, or
“final cause,” of its movement—why
it goes downward instead of up or
sideways—is that it is seeking the
center of the Earth (see pp.42–43).
The final cause of the action of
pushing the rock is to see how far
it will roll. The rock’s movement
is also determined by formal and
material causes.

44 45FOUNDATIONS

Purposes in nature

“It is [...] THE UNMOVED MOVER
necessary
always to Aristotle’s universe had no beginning, but Aristotle believed that something must
investigate have set the heavenly bodies in motion, since everything is caused by something
the supreme else. However, this raises two questions: What caused that cause, and what
cause of moved the mover of the universe? Aristotle proposed the idea of a first cause,
every thing.” an “unmoved mover,” responsible for all the motion in the universe.

Aristotle, Physics (4th century bce) FIRST
CAUSE

FIRE
The element fire rises to
take its position above the air.
A volcano’s purpose is to
enable the fire to escape from

the Earth.

2 MATERIAL CAUSE RAIN
The material cause is the Water in the air, in the form
rock’s physical composition. of clouds, has a downward
The rock is made of earth, tendency and falls to settle
so, because earthy things on the Earth, moistening it.
seek the center of the Earth,
it moves downward.

My purpose
is to think!

3 FORMAL CAUSE
The formal cause—the
shape of the rock’s trajectory—
is determined by the landscape.
The rock’s rolling and bouncing
are caused by the slopes and TREE
bumps of the hill. The nature of trees,
determined by their
4 FINAL CAUSE vegetative souls, is to
The rock comes to rest grow in order to produce
when it reaches the closest it fruit to reproduce.

can get to the center of the
Earth—the bottom of the hill.

Scholastic
philosophy

Medieval European culture was dominated by the Catholic Church,
and the classical philosophy of Plato and Aristotle was only gradually
assimilated into Christian teaching.

Catholic theology to newly founded universities in cities across Europe,
where Aristotelian logic and dialectical reasoning
The establishment of the Christian Church were taught as a method for examining theological
marked the end of the period of classical antiquity. arguments, and to provide rational justification
Philosophy was regarded with some suspicion by for the various pillars of Christian faith.
early Christians, who considered its basis in reason,
rather than faith, as incompatible with Christian Although the first translations of Greek
doctrine. There were some, such as Augustine of philosophers originated in southern Europe, with
Hippo (354–430 ce) and Boethius (c.477–524), who its links to the Islamic world, scholasticism arose
found ways to reconcile the idealist philosophy of in the scholarly work of Christian philosophers,
Plato with their faith, but for several centuries, the such as John Scotus Eriugena in Ireland in the 9th
Church’s monopoly on learning prevented the spread century. By the 12th century, the scholastic tradition
of classical philosophy in Europe. This changed in the was flourishing across Europe. Among its most
12th century, when medieval scholars rediscovered influential philosophers were Anselm of Canterbury
and translated the classical Greek texts. Many (1033/4–1109), Peter Abelard (1079–1142), Duns
of these had been preserved by Islamic scholars, Scotus (c.1266–1308), William of Ockham (c.1287–
who had translated them into Arabic. 1347), and, a major figure in medieval European
philosophy, Thomas Aquinas (1225–1274).
Although it was relatively simple to incorporate
Plato’s idealist and sometimes mystical ideas, Aristotle’s The schools that were established to provide
texts seemed at first to be contrary to Catholic dogma. scholastic education thrived for several centuries, and
His systematic reasoning, however, inspired a new many still exist today. However, with the arrival of the
approach to teaching, which became known as Renaissance, scholasticism’s emphasis on theology
scholasticism. Education spread from the monasteries was replaced by scientific and humanist ideas.

CREATING ETERNITY The ontological argument

A major stumbling block for Christian philosophers In attempting to reconcile faith and reason, a problem for
trying to integrate Aristotle into Catholic doctrine was scholastic philosophers was to provide a rational argument
Aristotle’s assertion that the universe has no end and for the existence of God. Probably the first of the Christian
no beginning, contradicting the Biblical description of philosophers to present such an argument was Anselm
God’s creation of the world. Thomas Aquinas, however, of Canterbury. His reasoning, known as the ontological
believed that since human reason and Christian doctrine argument, defines God as “that than which nothing greater
are both gifts from God, they cannot be contradictory. can be thought.” From that premise, he methodically shows
Using his God-given reason, he argued that Aristotle that if God exists in our imagination, then an even greater
was not mistaken in his concept of an eternal universe, God is possible: one that exists in reality. Thomas Aquinas
but that God was indeed its creator: in the beginning, later identified four other arguments for the existence of
God created the universe, but could have also created God, derived from Aristotle’s idea of an “unmoved mover”
a universe that is eternal. or first cause (see p.45).

FOUNDATIONS 46 47
Scholastic philosophy

5 “For I do not seek 6
IF GOD EXISTS to understand in THEREFORE, GOD
ONLY IN OUR order to believe, but
IMAGINATIONS, HE I believe in order MUST EXIST IN
WOULDN’T BE THE to understand.” REALITY
GREATEST THING
CONCEIVABLE, Anselm of Canterbury (11th century)
BECAUSE GOD IN
REALITY WOULD 4
THINGS THAT EXIST
BE BETTER
IN REALITY ARE
3 ALWAYS BETTER
THINGS CAN THAN THINGS THAT
EXIST ONLY IN OUR EXIST ONLY IN OUR
MINDS OR THEY
CAN EXIST IN MINDS

REALITY

2
GOD EXISTS AS AN
IDEA IN THE MIND

1
GOD IS THE
GREATEST THING
WE CAN THINK OF

Transubstantiation

Using the Aristotelian notions of substance, matter, and form,
Thomas Aquinas argued that, in the Catholic Mass, bread and wine
actually become the body and blood of Jesus.

Changing form body and blood of Christ, which the of, that undergo this change, but
Catholic Church claimed took place. their form. He argued that the
One of the most important To do this, Aquinas turned to consecration of the bread and wine
philosophers of the scholastic Aristotle, whose ideas were only changes their function or purpose—
tradition (see pp.46–47), Aquinas gradually gaining acceptance by as food and drink—into a sacred
(1225–1274) was largely responsible Christian philosophers. offering. And, therefore, by changing
for incorporating Aristotelian their essential properties, the
ideas into Christian theology. In true scholastic fashion, substance (the combination of both
The down-to-Earth philosophy of Aquinas rigorously applied matter and form) of the bread and
Aristotle (see pp.38–45) appeared rational argument to what seemed wine is transformed into the flesh
to be at odds with several tenets to be simply an article of faith. and blood of Christ.
of Christian dogma—not least that According to Aristotle, substance is
God created the universe—but a mixture of both matter and form CHRIST
Aquinas saw that it was not only (see p.41). Transubstantiation is a CRUCIFIED
compatible with Catholic doctrine, transformation of one substance
but actually helped to explain it. into another: specifically from
bread and wine into flesh and
A particularly tricky problem blood. And so, Aquinas reasoned
was how to provide a rational, that it is not the matter of the bread
philosophical justification for belief and wine, the physical materials
in transubstantiation—the actual they are made
changing of bread and wine into the

“Reason in man is rather
like God in the world.”

St. Thomas Aquinas (13th century)

WINE BREAD

Substances BLOOD BODY

According to Catholic doctrine, the bread and
wine consumed by the congregation in the Mass
are transformed by the prayers said by the priest
into the body and blood of Christ. However, in
Aristotelian terms, it is not their matter that is
altered, but their form—the function that they serve
and their essential properties. Their physical, or
“accidental” properties (see p.39), remain the same.