“You must accept the truth from whatever source it comes.”
--Maimonides
Why Study Philosophy?
Whether a person realizes it or not, his or her thinking has been influenced by philosophers
who lived hundreds or thousands of years ago. Men such as Plato, Aristotle, and
Thomas Aquinas are still having a profound impact on modern philosophy and theology. One can better understand the present
trends in academic circles if the past is better understood. This syllabus is
largely a compilation of class notes and class lectures by Norman Geisler.
Throughout world history, various philosophical worldviews have dominated at different
times. From 600 B.C. to A.D. 400 the religious emphasis was on polytheism (many gods) and henotheism (a super-god like Zeus).
From A.D. 500 to 1500, theism was the dominant religious worldview. Agnosticism was dominant between 1500 and 1900. Atheism
has been the dominant view since 1900. This is evident in the teachings of Darwinian evolution and secular humanism that have
dominated education and other areas of public life.
Of course it would be oversimplification to suggest that there were not groups of people
within each of these time periods that were exceptions to the dominant view in intellectual circles. This syllabus is not
exhaustive. This is really a list of ancient and medieval philosophers of western culture. The section on ancient philosophy
looks at more than two dozen philosophers who helped to lay the groundwork for much of western thought that was to follow. The Pre-Socratic philosophers were polytheistic. They had a difficult time reconciling
their first principle with their view of God.
The section on medieval philosophy only looks at a handful of the most important western
philosophers, though these men are examined in more detail than their ancient predecessors. Many of the questions unanswered
by the ancient philosophers were answered, due largely to the influence of Christianity.
I.
Ancient Philosophy (Pre-Socratic [600 B.C.] through
Plotinus [A.D. 250] )
Several important philosophers preceded the “big three” that have been household
names for more than 2400 years. Few have heard of their names. Fewer still know anything they taught or wrote. Yet, these
individuals set the stage for the teachings of Socrates, Plato, and Aristotle. The first of these is Thales.
- Thales—founder of Greek philosophy
1. Thales lived c. 640-545 B.C. in Miletus, Iona.
2. He founded Greek philosophy near the time of the destruction
of the Jewish temple (586 B.C.)
3. He had knowledge of science and philosophy.
a. According to Herodotus, he accurately predicted
a solar eclipse in 585 B.C.
b. He constructed an almanac.
c. He introduced the Phoenician practice of guiding
a ship’s course by the constellation Little Bear.
4. Epistemology
a. He asked, “What is the ultimate nature of
the world?”
b. He believed that the Earth was a flat disk that floated
on water.
5. Metaphysics
a. He believed the primary element was water, and
that all things were various forms of that one element.
b. He was polytheistic.
c. He was the first to conceive of the idea of unity
in diversity.
- Anaximander—first Greek evolutionist
1. He also lived c. 640 to 546 B. C. and resided in Miletus, Iona.
2. He was a student of Thales.
3. He constructed a map of the Black
Sea.
4. He used prose to communicate his philosophical theories.
5. Epistemology
a. Anaximander referred to the primary element as
“apeiron” which was infinite in extent and indefinite in nature.
b. Apeiron was the “material cause” of the
universe. He was the first to use the phrase “material cause.”
6. Metaphysics
a. He was the first naturalist. He denied the existence
of all gods and attempted to answer how the world developed naturally.
b. Eternal motion causes many co-existent worlds to come
into being.
c. He taught that man was born from animals of another
species.
- Anaximenes—the airhead
1. He also lived c. 640 to 546 B. C. in Miletus,
Iona.
2. He was a younger associate of Anaximander.
3. There currently exists only a small fragment of a book
he wrote.
4. Epistemology
a. Anaximenes believed that the primary element was
air.
b. He agreed with his predecessors that one could know
things as they are (realism).
5. Metaphysics
a. He believed in innumerable gods from the air which
act as primordial elements. This is similar to the Hindu view of many gods and one ultimate reality.
b. The earth is flat and floats in the air.
- Pythagoras—Founder of Geometry and the
Pythagorean Theorem
1. He lived and taught at the end of the 6th
century in Samia.
2. He founded an ascetic religious society with the goals
of purity and purification.
3. He believed that music, mathematics, and practices of
silence could help tend to the soul.
4. The number “10” had a special religious
significance.
5. He was the first person to use the label “philosopher”
(lover of wisdom).
6. He is best known for the development of what is today
called the Pythagorean Theorem.
7. Epistemology
a. The ultimate reality is numbers. The universe
can be explained in terms of numbers.
b. Things can be understood or known as they are perceived.
8. Metaphysics
a. Pythagorus believed in a form of re-incarnation.
He was a dualist;
he held that the body was imprisoned in the soul.
b. Matter is infinitely divisible.
c. The essence of a thing is determined by its structure
rather than the “stuff” of which it is made.
d. The earth is spherical and is not the center of the
universe.
- Heraclitus—the dark philosopher (esoteric);
flux philosopher
1. He lived c. 540 to 475 B. C. in Ephesus.
2. He taught in an esoteric, prophetic way
3. Epistemology
a. Knowledge is obtained by information gained from
the senses combined with reason.
b. Sense experience demonstrates that everything is in
a state of flux. Everything is a process. “No man steps into the same river twice.”
4. Metaphysics
a. The primary element is fire.
b. He said, “No man steps into the same river twice.”
c. Nothing is in a state of being, but in a state
of becoming.
d. He was the first to write extensively of unity in diversity
and difference in unity.
e. Reality is one and many at the same time (pantheism).
God is the One and is the universal Reason.
f. “There is a universal Logos; all flux is
relative to this Logos.”
g. Heraclitus attempted to be practical and moral in his
philosophy.
- Xenophanes
1. He was a poet who lived 570 to 480 B.C. in Colophon, Iona.
2. He was a disciple of Anaximander.
3. He was reputed as the founder of the Eleatic School.
4. Epistemology
a. Xenophanes used poetry to emphasize unity and
oneness.
b. He hesitated to use the word “knowledge”
from the cosmic explanations.
5. Metaphysics
a. He was a henotheist—believed that there
was a Supreme God who was greater than all other gods and men.
b. The nature of God is eternal, unmovable, unlike mortals
in either thought or form.
c. He attacked the idea of anthropomorphic Greek
gods; he said that horses would paint the form of gods like horses.
- Parmenides
1. He lived 515 to 450 B.C. in Elea, Italy.
2. He was a pupil of Xenophanes and possibly knew Socrates
as a young man.
3. He is the true founder of the Eleatic School.
4. He wrote The
Way of Truth and The Way of Belief or Opinion.
5. Epistemology
a. He Assumed the Law of Non-Contradiction and laws
of thought.
b. Parmenides “introduced the important distinction
between Reason and Sense, Truth and Appearance.”
c. “Knowledge is obtained through a combination
of sense-perception and reason.”
6. Metaphysics
a. “The One is sensual and material. Being,
or the One, is definite, determinate, complete, indestructible, unchangeable, spatially finite and spherical in shape. It
is temporally infinite, having neither beg9nning nor end.”
b. Argument for monism:
1) “There is only one thing in the universe, because
if there were many they would have to differ.
2) There are only two ways to differ, either by being or
non-being (nothing).
3) Things cannot differ by non-being because to differ
by nothing is to not differ at all.
4) Things cannot differ by being because being is that
which they have in common (makes them identical).
5) Therefore there are no differences and no two beings;
there is only one being in the universe, hence, monism.”
c. Premise #4 above is incorrect.
- Zeno
1. He lived c. 490 to 430 B.C. in Elea, Italy.
2. There are no extant writings, but later writers recorded
his “five famous paradoxes.”
3. Epistemology
a. One cannot trust his senses.
b. “True being is found through thought, not sense.”
4. Metaphysics
a. “Motion is an illusion and impossible.”
b. He defended Parmenides monistic materialism.
- Melissus
1. He was a Samian that lived in the 5th century
B.C.
2. He was a student of Parmenides.
3. Epistemology
a. What is perceived by the senses is an illusion.
b. “True being is found through thought, not sense.”
4. Metaphysics
a. Held to the view that Being is infinite in time
and space and is materially perfect as well.
b. Being is unchangeable.
c. There is no pain of grief in the One.
d. Everything is full; there is no void or vacuum.
e. Taught that the Being of the monists is not worthy
of worship since it is “static and cold.”
f. Being is indivisible.
- Empedocles—the four elements philosopher
1. He lived c. 493-433 B.C. in Sicily.
2. He is the first philosopher of which remains a great
deal of information.
3. He was active in politics and contributed to medicine.
4. He wrote On Nature
and Purifications.
5. Epistemology
a. The senses can be trusted.
b. The world of senses is becoming, and gives us a way
to know being.
c. He saw no distinction between thought and perception.
6. Metaphysics
a. All matter is reducible to the four elements of
earth, air, fire, and water.
b. The history of the universe is circular; “there
are periodic world cycles.”
c. “Matter is eternal and indestructible.”
d. Taught re-incarnation.
e. Eros love is a unifying factor in the universe.
f. God is “immediately certain,” but
cannot be proved.
g. Nature reveals God in three levels.
1) Four primary elements are imperishable.
2) “Dualism—love and hate move the corporal
world.”
3) “Monism—the state of unity, sphirous, achieved
by love.”
- Anaxagoras—the “Nous” philosopher
1. He lived c. 500 to 428 B.C. He was born in Clazomenae, Asia Minor and moved to Athens c. 480 B.C. and
eventually settled in Miletus, Iona.
2. Epistemology
a. One cannot trust the senses to understand the
true nature of the world.
b. The Mind (nous) contributes to the understanding of
the world.
3. Metaphysics
a. Being is unchangeable; matter is indestructible.
b. “In everything there is a portion of everything.”
c. He introduced the concept of “nous”
and taught that it has “power over all things, set in order all things, and is present in all living things.”
d. “Nous” is material in nature. It is the
thinnest of all material things.
e. Nous is eternal and sets matter, which is also
eternal, in motion.
- Diogenes
1. He lived c. 470 to 399 B.C. from Apollonia.
2. He offered one of the first forms of the Teleological
argument for the existence of God.
3. Metaphysics
a. Diogenes views nature as a machine.
b. There is more than one element, but air was the primal
substance common to all elements.
c. Change is impossible without a standard or reference
point. This standard is the “nous” or God.
d. He was a panentheist.
- Leucippus—founder of Atomism
1. He lived during the mid 400 B. C. in Miletus.
2. He founded the Atomist philosophy.
3. He wrote The Great Diakosmos.
4. Epistemology—“The world is known through
a purely mechanical account and explanation of reality.”
5. Metaphysics
a. Leucippus described atoms as indivisible units
which are infinite in number and always in motion. Atoms differ in shape and the space they occupy, not in substance.
b. Everything happens by reason and necessity. There are
no real accidents.
c. The soul is made up of spherical atoms.
d. He did not acknowledge the need for a Necessary Cause
of the universe.
e. He was a pantheist.
- Democritus-Key Atomist
1. He lived c. 460 to 370 B.C. in Thrace. He as head of a school at Abdera.
2. He is the key philosopher in the Atomist philosophy.
3. Epistemology
a. Democritus believed that sense-knowledge is not
true knowledge.
b. He had a mechanical understanding of sensation—that
“images pass through the air and are subject to distortion.
4. Metaphysics
a. He taught that atoms have size and shape, but
no weight.
b. He believed in a soul that existed in living things
as well as dead bodies and rocks.
c. He taught that the Greek gods appeared as god-men
which were personifications of natural phenomena.
5. Ethics—The key to happiness is moral wisdom with
moderation.
- Protagoras—the grammar philosopher and
first ancient relativist
1. He was a sophist that lived c. 481 to 411 B.C. from
Thrace. He also lived much of his time
in Athens.
2. He was a “pioneer in the study and science of
grammar.”
3. He wrote On Truth
and On the Gods
4. Epistemology
a. “There is no reality of the way things are,
independently of the way we talk about it.”
b. He used a dialectical method in teaching that demonstrated
two contradictory views on everything.
5. Metaphysics
a. “Man is the measure of all things, of those
that are that they are, of those that are not that they are not.”
b. He was agnostic about the existence of the gods.
6. Ethics
a. We should not view ethical questions as being
true or false, but as being sounder, or more useful.
b. Protagoras was a relativist.
- Gorgias—the first agnostic
1. Gorgias was a Sophist that lived c. 483 to 375 B.C.
from Sicily. He spent time in Athens.
2. He was a student of Empedocles.
3. He began in philosophy, later renounced it, and devoted
himself to rhetoric.
4. He wrote On Not-being
or Nature.
5. Epistemology
a. He taught that nothing exists, and that even if
it did, it could not be known.
b. If knowledge of being ever existed, it could not be
imparted.
6. Metaphysics—He followed Parminedes argument and
believed that nothing exists.
- Cratylus
1. He lived c. 428 to 348 B.C. in Athens and was an older contemporary of Plato and a disciple of Heraclitus.
2. Epistemology
a. He taught that one could not even step into the
same river once.
b. “The world of sense-perception is a world of flux,
and so not the right subject matter for true and certain knowledge.”
3. Metaphysics—He was not sure that anything existed,
including himself.
- Thrasymachus
1. He was a sophist from Chalcedon
2. Ethics—He believed that “might makes right.”
- Socrates
1. He lived from 470 to 399 B.C. and
