Western philosophy
History of Western philosophy from its development among the ancient
Greeks to the present.
Ancient Greek and Roman philosophy » The pre-Socratic philosophers »
Cosmology and the metaphysics of matter » Pluralistic cosmologies
Parmenides had an enormous influence on the further development of
philosophy. Most of the philosophers of the following two generations
tried to find a way to reconcile his thesis that nothing comes into
being nor passes away with the evidence presented to the senses.
Empedocles of Acragas (c. 490–430 bc) declared that there are four
material elements (he called them the roots of everything) and two
forces, love and hate, that did not come into being and would never pass
away, increase, or diminish. But the elements are constantly mixed with
one another by love and again separated by hate. Thus, through mixture
and decomposition, composite things come into being and pass away.
Because Empedocles conceived of love and hate as blind forces, he had to
explain how, through random motion, living beings could emerge. This he
did by means of a somewhat crude anticipation of the theory of the
survival of the fittest. In the process of mixture and decomposition,
the limbs and parts of various animals would be formed by chance. But
they could not survive on their own; they would survive only when, by
chance, they had come together in such a way that they were able to
support and reproduce themselves. It was in this way that the various
species were produced and continued to exist.
Anaxagoras of Clazomenae (c. 500–c. 428 bc), a pluralist, believed
that because nothing can really come into being, everything must be
contained in everything, but in the form of infinitely small parts. In
the beginning, all of these particles had existed in an even mixture, in
which nothing could be distinguished, much like the indefinite apeiron
of Anaximander. But then nous, or intelligence, began at one point to
set these particles into a whirling motion, foreseeing that in this way
they would become separated from one another and then recombine in the
most various ways so as to produce gradually the world in which human
beings live. In contrast to the forces assumed by Empedocles, the nous
of Anaxagoras is not blind but foresees and intends the production of
the cosmos, including living and intelligent beings; however, it does
not interfere with the process after having started the whirling motion.
This is a strange combination of a mechanical and a nonmechanical
explanation of the world.
By far of greatest importance for the later development of philosophy
and physical science was an attempt by the atomists Leucippus (flourished 5th century bc) and
Democritus (c. 460–c. 370 bc) to solve
the Parmenidean problem. Leucippus found the solution in the assumption
that, contrary to Parmenides’ argument, the nothing does in a way
exist—as empty space. There are, then, two fundamental principles of the
physical world, empty space and filled space—the latter consisting of
atoms that, in contrast to those of modern physics, are real atoms; that
is, they are absolutely indivisible because nothing can penetrate to
split them. On these foundations, laid by Leucippus, Democritus appears
to have built a whole system, aiming at a complete explanation of the
varied phenomena of the visible world by means of an analysis of its
atomic structure. This system begins with elementary physical problems,
such as why a hard body can be lighter than a softer one. The
explanation is that the heavier body contains more atoms, which are
equally distributed and of round shape; the lighter body, however, has
fewer atoms, most of which have hooks by which they form rigid gratings.
The system ends with educational and ethical questions. A sound and
cheerful person, useful to his fellows, is literally well composed.
Although destructive passions involve violent, long-distance atomic
motions, education can help to contain them, creating a better
composure. Democritus also developed a theory of the evolution of
culture, which influenced later thinkers. Civilization, he thought, is
produced by the needs of life, which compel human beings to work and to
make inventions. When life becomes too easy because all needs are met,
there is a danger that civilization will decay as people become unruly
and negligent.
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Empedocles
Greek philosopher and scholar
born c. 490 bc, Acragas, Sicily
died 430, the Peloponnese, Greece
Main
Greek philosopher, statesman, poet, religious teacher, and
physiologist.
According to legend only, Empedocles was a self-styled
god who brought about his own death, as dramatized by the
English poet Matthew Arnold in “Empedocles on Etna,” by
flinging himself into the volcanic crater atop Mount Etna to
convince followers of his divinity. To his contemporaries he
did indeed seem more than a mere mortal; Aristotle reputedly
hailed him as the inventor of rhetoric, and Galen regarded
him as the founder of Italian medicine. Lucretius admired
his hexametric poetry. Nothing remains of the various
writings attributed to him other than 400 lines from his
poem Peri physeōs (“On Nature”) and fewer than 100 verses
from his poem Katharmoi (“Purifications”).
Although strongly influenced by Parmenides, who
emphasized the unity of all things, Empedocles assumed
instead that all matter was composed of four essential
ingredients, fire, air, water, and earth, and that nothing
either comes into being or is destroyed but that things are
merely transformed, depending on the ratio of basic
substances, to one another. Like Heracleitus, he believed
that two forces, Love and Strife, interact to bring together
and to separate the four substances. Strife makes each of
these elements withdraw itself from the others; Love makes
them mingle together. The real world is at a stage in which
neither force dominates. In the beginning, Love was dominant
and all four substances were mixed together; during the
formation of the cosmos, Strife entered to separate air,
fire, earth, and water from one another. Subsequently, the
four elements were again arranged in partial combinations in
certain places; springs and volcanoes, for example, show the
presence of both water and fire in the Earth.
Apparently a firm believer in the transmigration of
souls, Empedocles declared that those who have sinned must
wander for 30,000 seasons through many mortal bodies and be
tossed from one of the four elements to another. Escape from
such punishment requires purification, particularly
abstention from the flesh of animals, whose souls may once
have inhabited human bodies.
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Anaxagoras
Greek philosopher
born c. 500 bc, Clazomenae, Anatolia [now in Turkey]
died c. 428, Lampsacus
Main
Greek philosopher of nature remembered for his cosmology and
for his discovery of the true cause of eclipses. He was
associated with the Athenian statesman Pericles.
About 480 Anaxagoras moved to Athens, then becoming the
centre of Greek culture, and brought from Ionia the new
practice of philosophy and the spirit of scientific inquiry.
After 30 years’ residence in Athens, he was prosecuted on a
charge of impiety for asserting that the Sun is an
incandescent stone somewhat larger than the region of the
Peloponnese. The attack on him was intended as an indirect
blow at Pericles, and, although Pericles managed to save
him, Anaxagoras was compelled to leave Athens. He spent his
last years in retirement at Lampsacus.
Only a few fragments of Anaxagoras’ writings have been
preserved, and several different interpretations of his work
have been made. The basic features, however, are clear. His
cosmology grows out of the efforts of earlier Greek thinkers
who had tried to explain the physical universe by an
assumption of a single fundamental element. Parmenides,
however, asserted that such an assumption could not account
for movement and change, and, whereas Empedocles sought to
resolve this difficulty by positing four basic ingredients,
Anaxagoras posited an infinite number. Unlike his
predecessors, who had chosen such elements as heat or water
as the basic substance, Anaxagoras included those found in
living bodies, such as flesh, bone, bark, and leaf.
Otherwise, he asked, how could flesh come from what is not
flesh? He also accounted for biological changes, in which
substances appear under new manifestations: as men eat and
drink, flesh, bone, and hair grow. In order to explain the
great amount and diversity of change, he said that “there is
a portion of every thing, i.e., of every elemental stuff, in
every thing,” but “each is and was most manifestly those
things of which there is most in it.”
The most original aspect of Anaxagoras’ system was his
doctrine of nous (“mind,” or “reason”). The cosmos was
formed by mind in two stages: first, by a revolving and
mixing process that still continues; and, second, by the
development of living things. In the first, all of “the
dark” came together to form the night, “the fluid” came
together to form the oceans, and so on with other elements.
The same process of attraction of “like to like” occurred in
the second stage, when flesh and other elements were brought
together by mind in large amounts. This stage took place by
means of animal and plant seeds inherent in the original
mixture. The growth of living things, according to
Anaxagoras, depends on the power of mind within the
organisms that enables them to extract nourishment from
surrounding substances. For this concept of mind, Anaxagoras
was commended by Aristotle. Both Plato and Aristotle,
however, objected that his notion of mind did not include a
view that mind acts ethically—i.e., acts for the “best
interests” of the universe.
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Leucippus
Greek philosopher
flourished 5th century bc, probably at Miletus, on the
west coast of Asia Minor
Main
Greek philosopher credited by Aristotle and by Theophrastus
with having originated the theory of atomism. It has been
difficult to distinguish his contribution from that of his
most famous pupil, Democritus. Only fragments of Leucippus’
writings remain, but two works believed to have been written
by him are The Great World System and On the Mind. His
theory stated that matter is homogeneous but consists of an
infinity of small indivisible particles. These atoms are
constantly in motion, and through their collisions and
regroupings form various compounds. A cosmos is formed by
the collision of atoms that gather together into a “whirl,”
and the drum-shaped Earth is located in the centre of man’s
cosmos.
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Democritus
Greek philosopher
born c. 460 bc
died c. 370
Main
Greek philosopher, a central figure in the development of
the atomic theory of the universe.
Knowledge of Democritus’ life is largely limited to
untrustworthy tradition: it seems that he was a wealthy
citizen of Abdera, in Thrace; that he traveled widely in the
East; and that he lived to a great age. According to
Diogenes Laërtius, his works numbered 73; only a few hundred
fragments have survived, mostly from his treatises on
ethics.
Democritus’ physical and cosmological doctrines were an
elaborated and systematized version of those of his teacher,
Leucippus. To account for the world’s changing physical
phenomena, Democritus asserted that space, or the Void, had
an equal right with reality, or Being, to be considered
existent. He conceived of the Void as a vacuum, an infinite
space in which moved an infinite number of atoms that made
up Being (i.e., the physical world). These atoms are eternal
and invisible; absolutely small, so small that their size
cannot be diminished (hence the name atomon, or
“indivisible”); absolutely full and incompressible, as they
are without pores and entirely fill the space they occupy;
and homogeneous, differing only in shape, arrangement,
position, and magnitude. But, while atoms thus differ in
quantity, differences of quality are only apparent, owing to
the impressions caused on our senses by different
configurations and combinations of atoms. A thing is hot or
cold, sweet or bitter, or hard or soft only by convention;
the only things that exist in reality are atoms and the
Void. Thus, the atoms of water and iron are the same, but
those of water, being smooth and round and therefore unable
to hook onto one another, roll over and over like small
globes, whereas those of iron, being rough, jagged, and
uneven, cling together and form a solid body. Because all
phenomena are composed of the same eternal atoms, it may be
said that nothing comes into being or perishes in the
absolute sense of the words, although the compounds made out
of the atoms are liable to increase and decrease, explaining
a thing’s appearance and disappearance, or “birth” and
“death.”
Just as the atoms are uncaused and eternal, so too,
according to Democritus, is motion. Democritus posited the
fixed and “necessary” laws of a purely mechanical system, in
which there was no room for an intelligent cause working
with a view to an end. He explained the origin of the
universe as follows. The original motion of the atoms was in
all directions—it was a sort of “vibration”; hence there
resulted collisions and, in particular, a whirling movement,
whereby similar atoms were brought together and united to
form larger bodies and worlds. This happened not as the
result of any purpose or design but rather merely as the
result of “necessity”; i.e., it is the normal manifestation
of the nature of the atoms themselves. Atoms and void being
infinite in number and extent, and motion having always
existed, there must always have been an infinite number of
worlds, all consisting of similar atoms in various stages of
growth and decay.
Democritus devoted considerable attention to perception
and knowledge. He asserted, for example, that sensations are
changes produced in the soul by atoms emitted from other
objects that impinge on it; the atoms of the soul can be
affected only by the contact of other atoms. But sensations
such as sweet and bitter are not as such inherent in the
emitted atoms, for they result from effects caused merely by
the size and shape of the atoms; e.g., sweet taste is due to
round and not excessively small atoms. Democritus also was
the first to attempt to explain colour, which he thought was
due to the “position” (which he differentiated from shape)
of the constituent atoms of compounds. The sensation of
white, for instance, is caused by atoms that are smooth and
flat so as to cast no shadow; the sensation of black is
caused by rough, uneven atoms.
Democritus attributed popular belief in the gods to a
desire to explain extraordinary phenomena (thunder,
lightning, earthquakes) by reference to superhuman agency.
His ethical system, founded on a practical basis, posited an
ultimate good (“cheerfulness”) that was “a state in which
the soul lives peacefully and tranquilly, undisturbed by
fear or superstition or any other feeling.”
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Ancient Greek and Roman philosophy » The pre-Socratic philosophers »
Epistemology of appearance
All of the post-Parmenidean philosophers, like Parmenides himself,
presupposed that the real world is different from the one that human
beings perceive. Thus arose the problems of epistemology, or theory of
knowledge. According to Anaxagoras, everything is contained in
everything. But this is not what people perceive. He solved this problem
by postulating that, if there is a much greater amount of one kind of
particle in a thing than of all other kinds, the latter are not
perceived at all. The observation was then made that sometimes different
persons or kinds of animals have different perceptions of the same
things. He explained this phenomenon by assuming that like is perceived
by like. If, therefore, in the sense organ of one person there is less
of one kind of stuff than of another, that person will perceive the
former less keenly than the latter. This reasoning was also used to
explain why some animals see better at night and others during the day.
According to Democritus, atoms have no sensible qualities, such as
taste, smell, or colour, at all. Thus, he tried to reduce all of them to
tactile qualities (explaining a bright white colour, for instance, as
sharp atoms hitting the eye like needles), and he made a most elaborate
attempt to reconstruct the atomic structure of things on the basis of
their apparent sensible qualities.
Also of very great importance in the history of epistemology was Zeno
of Elea (c. 495–c. 430 bc), a younger friend of Parmenides. Parmenides
had, of course, been severely criticized because of the strange
consequences of his doctrine: that in reality there is no motion and no
plurality because there is just one solid being. To support him,
however, Zeno tried to show that the assumption that there is motion and
plurality leads to consequences that are no less strange. This he did by
means of his famous paradoxes, saying that the flying arrow rests since
it can neither move in the place in which it is nor in a place in which
it is not, and that Achilles cannot outrun a turtle because, when he has
reached its starting point, the turtle will have moved to a further
point, and so on ad infinitum—that, in fact, he cannot even start
running, for, before traversing the stretch to the starting point of the
turtle, he will have to traverse half of it, and again half of that, and
so on ad infinitum. All of these paradoxes are derived from the problem
of the continuum. Although they have often been dismissed as logical
nonsense, many attempts have also been made to dispose of them by means
of mathematical theorems, such as the theory of convergent series or the
theory of sets. In the end, however, the logical difficulties raised in
Zeno’s arguments have always come back with a vengeance, for the human
mind is so constructed that it can look at a continuum in two ways that
are not quite reconcilable.
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Zeno of Elea
Greek philosopher and mathematician
(c. 495 bc–c. 430 bc), Greek philosopher and mathematician,
whom Aristotle called the inventor of dialectic. He is
especially known for his paradoxes that contributed to the
development of logical and mathematical rigour and that were
insoluble until the development of precise concepts of
continuity and infinity.
Zeno was famous for the paradoxes whereby, in order to
recommend the Parmenidean doctrine of the existence of “the
one” (i.e., indivisible reality), he sought to controvert
the common-sense belief in the existence of “the many”
(i.e., distinguishable qualities and things capable of
motion). Zeno was the son of a certain Teleutagoras and the
pupil and friend of Parmenides. In Plato’s Parmenides,
Socrates, “then very young,” converses with Parmenides and
Zeno, “a man of about forty”; but it may be doubted whether
such a meeting was chronologically possible. Plato’s account
of Zeno’s purpose (Parmenides), however, is presumably
accurate. In reply to those who thought that Parmenides’
theory of the existence of “the one” involved
inconsistencies, Zeno tried to show that the assumption of
the existence of a plurality of things in time and space
carried with it more serious inconsistencies. In early youth
he collected his arguments in a book, which, according to
Plato, was put into circulation without his knowledge.
Zeno made use of three premises: first, that any unit has
magnitude; second, that it is infinitely divisible; and
third, that it is indivisible. Yet he incorporated arguments
for each: for the first premise, he argued that that which,
added to or subtracted from something else, does not
increase or decrease the second unit is nothing; for the
second, that a unit, being one, is homogeneous and that
therefore, if divisible, it cannot be divisible at one point
rather than another; for the third, that a unit, if
divisible, is divisible either into extended minima, which
contradicts the second premise or, because of the first
premise, into nothing. He had in his hands a very powerful
complex argument in the form of a dilemma, one horn of which
supposed indivisibility, the other infinite divisibility,
both leading to a contradiction of the original hypothesis.
His method had great influence and may be summarized as
follows: he continued Parmenides’ abstract, analytic manner
but started from his opponents’ theses and refuted them by
reductio ad absurdum. It was probably the two latter
characteristics which Aristotle had in mind when he called
him the inventor of dialectic.
That Zeno was arguing against actual opponents,
Pythagoreans who believed in a plurality composed of numbers
that were thought of as extended units, is a matter of
controversy. It is not likely that any mathematical
implications received attention in his lifetime. But in fact
the logical problems which his paradoxes raise about a
mathematical continuum are serious, fundamental, and
inadequately solved by Aristotle.
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Ancient Greek and Roman philosophy » The pre-Socratic philosophers »
Metaphysics of number
All of the philosophies mentioned so far are in various ways
historically akin to one another. Toward the end of the 6th century bc,
however, there arose, quite independently, another kind of philosophy,
which only later entered into interrelation with the developments just
mentioned: the philosophy of Pythagoras of Samos (c. 580–c. 500 bc; ).
Pythagoras traveled extensively in the Middle East
and in Egypt and, after his return to Samos, emigrated to southern Italy
because of his dislike of the tyranny of Polycrates (c. 535–522 bc). At
Croton and Metapontum he founded a philosophical society with strict
rules and soon gained considerable political influence. He appears to
have brought his doctrine of the transmigration of souls from the Middle
East. Much more important for the history of philosophy and science,
however, was his doctrine that “all things are numbers,” which means
that the essence and structure of all things can be determined by
finding the numerical relations they express. Originally, this, too, was
a very broad generalization made on the basis of comparatively few
observations: for instance, that the same harmonies can be produced with
different instruments—strings, pipes, disks, etc.—by means of the same
numerical ratios—1:2, 2:3, 3:4—in one-dimensional extensions; the
observation that certain regularities exist in the movements of the
celestial bodies; and the discovery that the form of a triangle is
determined by the ratio of the lengths of its sides. But because the
followers of Pythagoras tried to apply their principle everywhere with
the greatest of accuracy, one of them—Hippasus of Metapontum (flourished
5th century bc)—made one of the most fundamental discoveries in the
entire history of science: that the side and diagonal of simple figures
such as the square and the regular pentagon are incommensurable (i.e.,
their quantitative relation cannot be expressed as a ratio of integers).
At first sight this discovery seemed to destroy the very basis of the
Pythagorean philosophy, and the school thus split into two sects, one of
which engaged in rather abstruse numerical speculations, while the other
succeeded in overcoming the difficulty by ingenious mathematical
inventions. Pythagorean philosophy also exerted a great influence on the
later development of Plato’s thought.
The speculations described so far constitute, in many ways, the most
important part of the history of Greek philosophy because all of the
most fundamental problems of Western philosophy turned up here for the
first time. One also finds here the formation of a great many concepts
that have continued to dominate Western philosophy and science to the
present day.
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Pythagoras
Greek philosopher and mathematician
born c. 580 bc, Samos, Ionia [now in Greece]
died c. 500, Metapontum, Lucania [now in Italy]
Main
Greek philosopher, mathematician, and founder of the
Pythagorean brotherhood that, although religious in nature,
formulated principles that influenced the thought of Plato
and Aristotle and contributed to the development of
mathematics and Western rational philosophy (see
Pythagoreanism).
Pythagoras migrated to southern Italy about 532 bc,
apparently to escape Samos’s tyrannical rule, and
established his ethico-political academy at Croton (now
Crotone, Italy).
It is difficult to distinguish Pythagoras’s teachings
from those of his disciples. None of his writings have
survived, and Pythagoreans invariably supported their
doctrines by indiscriminately citing their master’s
authority. Pythagoras, however, is generally credited with
the theory of the functional significance of numbers in the
objective world and in music. Other discoveries often
attributed to him (e.g., the incommensurability of the side
and diagonal of a square, and the Pythagorean theorem for
right triangles) were probably developed only later by the
Pythagorean school. More probably the bulk of the
intellectual tradition originating with Pythagoras himself
belongs to mystical wisdom rather than to scientific
scholarship.
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Hippasus of Metapontum
Greek philosopher
Hippasus of Metapontum (Ancient Greek: Ἵππασος), b. c.
500 B.C. in Magna Graecia, was a Greek philosopher. He was a
disciple of Pythagoras. To Hippasus (or Hippasos) is
attributed the discovery of the existence of irrational
numbers. More specifically, he is credited with the
discovery that the square root of 2 is irrational.
Until Hippasus' discovery, the Pythagoreans preached that
all numbers could be expressed as the ratio of integers.
Despite the validity of his discovery, the Pythagoreans
initially treated it as a kind of religious heresy and they
either exiled or murdered Hippasus. Legend has it that the
discovery was made at sea and that Hippasus' fellow
Pythagoreans threw him overboard.
But there are two other stories about Hippasus. The first
says that Hippasus was expelled from the Pythagorean school
because he published doctrines of Pythagoras, while the
second says that he was drowned at sea for revealing the
construction of the dodecahedron in the sphere and claiming
it as his own. But since the Pythagoreans' supposed pledge
to secrecy was most likely false[citation needed], the
authenticity of these stories is questioned.
He was also noted as an early experimenter in acoustics
and resonance. Few of his original works now survive.
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Ancient Greek and Roman philosophy » The pre-Socratic philosophers »
Anthropology and relativism
In the middle of the 5th century bc, Greek thinking took a somewhat
different turn through the advent of the Sophists. The name is derived
from the verb sophizesthai, “making a profession of being inventive and
clever,” and aptly described the Sophists, who, in contrast to the
philosophers mentioned so far, charged fees for their instruction.
Philosophically they were, in a way, the leaders of a rebellion against
the preceding development, which increasingly had resulted in the belief
that the real world is quite different from the phenomenal world. “What
is the sense of such speculations?” they asked, since no one lives in
these so-called real worlds. This is the meaning of the pronouncement of
Protagoras of Abdera (c. 485–c. 410 bc) that “man is the measure of all
things, of those which are that they are and of those which are not that
they are not.” For human beings the world is what it appears to them to
be, not something else; Protagoras illustrated his point by saying that
it makes no sense to tell a person that it is really warm when he is
shivering with cold because for him it is cold—for him, the cold exists,
is there.
His younger contemporary Gorgias of Leontini (flourished 5th century
bc), famous for his treatise on the art of oratory, made fun of the
philosophers in his book Peri tou mē ontos ē peri physeōs (“On That
Which Is Not; or, On Nature”), in which—referring to the “truly existing
world,” also called “the nature of things”—he tried to prove
(1) that
nothing exists,
(2) that if something existed, one could have no
knowledge of it, and
(3) that if nevertheless somebody knew something
existed, he could not communicate his knowledge to others.
The Sophists were not only skeptical of what had by then become a
philosophical tradition but also of other traditions. On the basis of
the observation that different nations have different rules of conduct
even in regard to things considered most sacred—such as the relations
between the sexes, marriage, and burial—they concluded that most rules
of conduct are conventions. What is really important is to be successful
in life and to gain influence over others. This they promised to teach.
Gorgias was proud of the fact that, having no knowledge of medicine, he
was more successful in persuading a patient to undergo a necessary
operation than his brother, a physician, who knew when an operation was
necessary. The older Sophists, however, were far from openly preaching
immoralism. They, nevertheless, gradually came under suspicion because
of their sly ways of arguing. One of the later Sophists, Thrasymachus of
Chalcedon (flourished 5th century bc), was bold enough to declare openly
that “right is what is beneficial for the stronger or better one”—that
is, for the one able to win the power to bend others to his will.
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Protagoras
Greek philosopher
born c. 485 bc, Abdera, Greece
died c. 410
Main
thinker and teacher, the first and most famous of the Greek
Sophists.
Protagoras spent most of his life at Athens, where he
considerably influenced contemporary thought on moral and
political questions. Plato named one of his dialogues after
him. Protagoras taught as a Sophist for more than 40 years,
claiming to teach men “virtue” in the conduct of their daily
lives. He is best known for his dictum “Man is the measure
of all things,” probably an expression of the relativity to
the individual of all perceptions and, according to some, of
all judgments as well. He acquired great wealth and
reputation from his teaching, prompting his appointment as
lawgiver for the Athenian colony of Thurii in Italy. Though
he adopted conventional moral ideas, Protagoras expressed
his agnostic attitude toward belief in the gods in
Concerning the Gods. He was accused of impiety, his books
were publicly burned, and he was exiled from Athens about
415 bc for the rest of his life.
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