The Philosopher's Way
A Text with Readings
FIFTH EDITION
CHAPTER
5
how can we know the
nature of reality?
Philosophical Foundations
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Heaven or earth? In this detail from Raphael’s School of Athens, Plato points to the heavens and Aristotle
motions toward the earth. While both philosophers believed that there was an ultimate reality, they disagreed
about which way to discover it. This chapter will introduce you to their debate and others.
Scala/Art Resource, NY
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Learning Objectives
5.1 Define the words reality and truth.
5.2 Explain Plato's idea of "Two Worlds."
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Learning Objectives
5.3 Describe Aristotle's view that reality
consists of the natural world and that
this natural world follows orderly
principles and laws.
5.4 Explain that Descartes was a
rationalist, believing that true
knowledge is produced by thinking
that is reflective, logical and
analytical.
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Chapter Overview
Click on the screenshot in presentation mode to view a video philosophical
foundations.
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5.1 What is the Nature of Reality?
• Reality refers to things the way they
really are.
• Truth refers to those statements that
are one hundred percent accurate.
• Metaphysics
• Epistemology
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5.1 What is the Nature of Reality?
• The Milesians
 Thales
 Anaximander
 Anaximenes
• Xenophanes and Heraclitus
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5.1 What is the Nature of Reality?
• Parmenides
• Leucippus and Democritus
• Legacy of the Pre-Socratic philosophers
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Is there anything in life that is permanent, or is the world constantly changing? Heraclitus said, “You
cannot step into the same river, for other waters are continually flowing on. Can you think of anything doesn’t
change over time?
Galyna Andrushko/Fotolia
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Heraclitus (c. 540–480 B.C.E.) The most influential of pre-Socratic philosophers; maintained all thing were in a
constant state of flux and that the governing principle of the universe is what is called logos.
Anastasios71/Shutterstock
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5.2 Reality is the Eternal Realm of
the Forms: Plato
•
•
•
•
•
Two worlds
What precisely are forms?
What are examples of ideal forms?
The divided line
The theory of innate ideas
 Rationalism
 Empiricism
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What are examples of ideal forms? Judges at dog shows evaluate the contestants in terms of how well they
conform to a breed standard. In what other areas are “examples” judged in terms of how closely they correspond
to an ideal?
Getty Images
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Figure 5.1
Plato’s Divided Line
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5.2 Reality is the Eternal Realm of
the Forms: Plato
• Plato, from Meno
• Analyzing Plato's theory of innate ideas
• The path to knowledge of reality: the
Cave allegory
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5.2 Reality is the Eternal Realm of
the Forms: Plato
• Plato, from The Republic
• Analyzing Plato's "Allegory of the Cave"
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How is the allegory of the cave a metaphor for achieving intellectual insight and wisdom? After reading
the passage from The Republic, can you describe what is happening in the painting?
Catacomb of Via Latina, Rome, Italy/Bridgeman Images
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Are reality shows “real”? Does the media tell the “truth”? How are the images we encounter on television
and in the mass media similar to Plato’s idea of a shadow puppet show? Why do some people who view television
and read information sources uncritically tend to believe that what they are viewing is “real”? Recognizing that
the perceptions we encounter in our daily lives are often incomplete, inaccurate, and distorted is essential to
beginning our journey toward illumination.
Robert Voets/Newscom
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5.2 Reality is the Eternal Realm of
the Forms: Plato
• Inspiring ascent to the forms: the
ladder of love
 Plato, from Symposium
 Analyzing Plato's Ladder of Love
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Aristotle (384–322 B.C.E.) This image, believed to be of Aristotle teaching an anatomy lesson, illustrates
Aristotle’s commitment to observation and his work in biology. One of the most important figures in the history of
philosophy, Aristotle conceptualized the branches of philosophy and contributed to theories in logic, metaphysics,
ethics, and political philosophy.
Bridgeman Images
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5.3: Reality is the Natural World:
Aristotle
• Aristotle's view of Plato's metaphysical
dualism
• Aristotle as philosophical naturalist
• Genuine knowledge
• The human soul cannot be separated
from the body.
• We are unique because of our ability to
reason.
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5.3: Reality is the Natural World:
Aristotle
• Aristotle's two categories
 Matter
 Form
• Hylomorphism
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5.3: Reality is the Natural World:
Aristotle
• Entelechy
 One of core concepts of Aristotle's entire
philosophy
 Everything in the universe has its own
unique purpose to fill.
 The formal element of people is the
soul.
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Does everything in nature have a unique purpose (entelechy)? An acorn is to be an oak tree, provided
that the conditions are right for its potential to be realized. Aristotle believed that everything in the universe has
its own unique purpose to fulfill.
Martin Novak/123 RF
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5.3: Reality is the Natural World:
Aristotle
• The Four Causes




Material
Formal
Efficient
Final
• Aristotle, from Metaphysics
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The Four Causes How does the process of forming an object through glassblowing illustrate Aristotle’s concept
of the Four Causes?
Brendan MacNeill/Alamy
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5.4: Can Reality Be Known?
Descartes
• René Descartes, from Meditations on
First Philosophy




Meditation
Meditation
Meditation
Meditation
I
II
III
IV
• Analyzing Descartes' radical doubt
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Making Connections: Your Beliefs
About the World
• You do have a theory of knowledge, your
own epistemology.
• Critical thinking abilities enable you to
develop the most informed beliefs and
construct the most enlightened
knowledge.
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Making Connections: Your Beliefs
About the World
• What exactly are "beliefs"?
•
•
•
•
Interpretation
Evaluation
Conclusion
Prediction
• The beliefs you form vary tremendously in
accuracy.
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Making Connections: Your Beliefs
About the World
• The beliefs you form vary tremendously
in accuracy.
 We work at evaluating the accuracy of
our beliefs by examining the reasons or
evidence that support them.
 How do we assess justification?
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What degree of certainty? How would you go about justifying your belief that Earth is round? What degree of
certainty would you give it?
Dorling Kindersley
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