Anaxagoras

BORN: c. 500 bce • Clazomenae, Greece

DIED: c. 428 bce • Lampsacus, Greece

Greek philosopher

Anaxagoras was one of the most famous of early Greek philosophers. He is credited with turning Athens into a center of ancient study and intellectual activity. Anaxagoras expanded on the work of earlier philosophers, especially those from the Milesian or Ionian School. These thinkers proposed that substances such as air, fire, water, or earth made up the universe. Anaxagoras, in contrast, proposed that the universe was made up of a substance that could be divided infinitely, or forever.

"Other things include a portion of everything, but mind is infinite and self-powerful and mixed with nothing … over all that has life, both greater and less, mind rules."

Anaxagoras, like many other philosophers of his time, sought to find an explanation for the source of motion by searching for an organizing principle. Anaxagoras believed this principle was what he called nous or "mind." His theory was that nous set unarranged matter in the universe into motion and created order from it. Because of his focus on this principle, Anaxagoras has been credited both with an advance towards theism, the concept of a personal creator-god involved in human affairs, and with the first steps toward atheism, or the total disbelief in god or gods. In placing nous as the beginning of creation, Anaxagorous paved the way for believing in a single creative force, God. Ironically, his philosophical concept of nous also helped lead to a rejection of all gods, for the beginning of the world and creation could now be explained in scientific terms rather than religious ones.

Early years

Anaxagoras was born in about 500 bce, into a wealthy and noble family in the town of Clazomenae in Ionia in Asia Minor. This strip of land along the coast of what is modern-day western Turkey was part of Greece during Anaxagoras's lifetime. About fifty years before Anaxagoras's birth, Ionia had been conquered by the Persians under Cyrus the Great. The Persians were harsh rulers, and in 498 bce the Greeks of Ionia rebelled against the current Persian ruler, Darius. The revolt was defeated in 492 bce, but led to the later Persian Wars. In these wars, Persia attempted to punish Athens for having helped the Ionian citizens in their rebellion. Roughly fifty years of periodic warfare followed.

Anaxagoras was born into complex times. His focus, however, was on the mind rather than military and political affairs. Although little is known of these early years of Anaxagoras's life, it is believed that as a young man he gave up his noble position and wealth in order to concentrate on science. Most likely he was aware of the intellectual activity that was occurring in the nearby seaport of Miletus, which had no priesthood or king that ruled as God's representative on Earth. There early philosophers sought to describe the nature of the universe using reason and logic. They formed the Ionian or Milesian School of writers and thinkers, which was the birthplace of Greek philosophy.

Thinkers such as Thales (c. 636–c. 546 bce), Anaximander (c. 611–c. 547 bce), and Anaximenes (sixth century bce) focused their attention on the study of nature. They were searching for an elemental building block of matter or for one primary substance or originating principle, the archê. The one primary substance or originating principle refers to the one substance that existed at the beginning of time. Anaximander defined the primary source of everything as apeiron, or the unlimited and infinite (forever). Anaximenes believed that everything was originally composed of air or vapor, the thinning and thickening of which gave substance to life. Heraclitus (c. 535–c. 475 bce), from Ephesus on the coast of Asia Minor, credited fire as the original substance that formed everything and declared change was the only constant in the universe. Such change, according to Heraclitus, was guided by logos, or reason. Heraclitus, though not Ionian, advanced this search for the primary building blocks of the universe by saying that there were four unchanging elements: earth, water, fire, and air. These elements were combined and separated by Love and Strife, his organizing principles.

Anaxagoras was aware of the work of these Ionian philosophers. Even before the age of twenty, when he departed for Athens, he saw that their arguments failed to explain movement and change. He was determined to create a theory that accounted for all aspects of the universe. In Athens, Anaxagoras became friends with the young statesman Pericles (c. 495–429 bce). Pericles rose to prominence in about 460 bce, becoming a popular political and military leader of the city. Anaxagoras was also said to be friends with other important Athenians, and some say he was even a teacher of the famous philosopher Socrates (469–399 bce), though this is unlikely.

Time in Athens

Anaxagoras's years in Athens were productive ones. By about 467 bce he produced his major work of writing, On Nature, only fragments of which exist today. Many quotations from Anaxagoras come from the works of later philosophers. In On Nature, Anaxagoras attempted to further the work of the earlier Ionian School thinkers. Instead of air, fire, water, and earth as the four elements of creation, Anaxagoras said that there were an infinite number of particles or "seeds" (spermata) that combined to create everything in the universe. These seeds, or building blocks, could be divided into smaller parts, or combined to form larger items. Anaxagoras claimed that this ability of matter to be divided or combined together accounted for the vast variety of forms in the universe.

Anaxagoras's creation of the cosmos

Anaxagoras held that these seeds were eternal and have always been in existence. For Anaxagoras, there was no such thing as a void or empty space. At the beginning of the cosmos (universe), such seeds were initially in one huge mass without shape or form. Through nous, or organizing principle, this mass was set in rotary motion. This motion caused the mass to separate out into smaller elements.

Anaxagors believed the creation of the world was due to this separating of the seeds and by the effect of the spinning motion on these seeds. The formation of the universe or cosmos took place in two stages. First was the revolving process, which separated and then remixed the particles. In this stage, all the dark particles came together to form night, and the fluid seeds joined to make the oceans. The friction in this rotary motion in turn caused heat, which set the stars and sun on fire.

The development of all living things came in the second stage, when the same types of seeds or particles attracted others like them. The separation of the seeds by the rotary motion was imperfect, as Anaxagoras noted, and therefore, according to his theory, there are a few seeds of everything in everything else. What makes something what we believe it to be is that it has a majority of seeds of one type. For example, white is white because it has a majority of white seeds, but it also contains black seeds. Hair is hair, because most of its seeds are of the hair type, but it also has parts of everything else in creation in it.

Ordering the universe and studying it

An important factor of Anaxagoras's theory is the action he claimed nous had upon the organization of the universe. This approach was popular with later philosophers such as Socrates (469–399 bce), Plato (428–348 bce), and Aristotle (384–322 bce), all of whom were highly concerned with ethical problems and how to live a good life. For them, the concept of an ordering principle to the universe, such as nous, was appealing. They criticized Anaxagoras, however, for not taking his theory further and explaining the purpose of such an ordering principle. Anaxagoras simply explained his theory of matter and motion but did not ask why it happened as it did.

Anaxagoras was also known for his work in astronomy (the study of the sun, moon, planets, stars, and objects found in space), which may have been inspired by the fall of a large meteorite, or mass of matter that falls to Earth from space, near Aegypotomi in 467 bce. He believed that the sun was a blazing ball of metal about the size of the Peloponessus, the major island of southern Greece. Anaxagoras went further, however, and said that the moon was made of similar matter as Earth and shone because it reflected light from the sun. From this, he went on to describe how Earth moves between the sun and moon, blocking the light and causing lunar eclipses. He also explained how the moon sometimes moves between Earth and sun, causing a solar eclipse.

Anaxagoras accused

Anaxagoras's theories of the universe angered some citizens of Athens because they challenged the accepted beliefs of the time. His friendship with Pericles may also have caused Anaxagoras trouble. Pericles had enemies, and these enemies ultimately targeted his friends. Some time around 450 bce Anaxagoras was imprisoned and charged with impiety, or disbelief in the gods. The reason for his imprisonment was his claim that the sun was only a huge mass of hot metal and not a god, as was commonly believed at the time. He was also accused of maintaining secret communications with the Persians, the enemy of Athens, and was sentenced to death. Pericles used his influence and had the death sentence changed to one of exile, which meant Anaxagoras's life was spared, but he was forced to live outside of Athens.

Exile in Lampsacus

Anaxagoras left Athens for Lampsacus, an ancient Greek city in northwestern Asia Minor. Many young Greeks came to study with him until his death in 429 bce. Few specifics are known of Anaxagoras's work in exile. However, a much later Roman author and architect mentioned that Anaxagoras created theater designs that allowed viewers to better see objects in the front and back of the stage. This suggests that Anaxagoras also may have done some philosophical work on perspective, perhaps the earliest of its kind. Perspective is the appearance to the eye of objects in respect to their relative distance and position.

Pericles

Pericles, a well-known speaker and patron of learning and the arts, was born around 493 bce in Athens. Although for much of his early life he was concerned with the theatre, in 461 bce he became involved in politics. He helped organize a vote in the popular assembly that took power away from the Areopagus, the ancient aristocratic council that ruled Athens. The vote left the Areopagus basically a legal court rather than a ruling council.

Pericles then initiated a number of democratic reforms in Athens, including the payment of salaries to state officials and the opening of such offices to commoners. He introduced laws that limited the power of the Athenian aristocrats, although this won him many enemies. He also established a truce with Athens's longtime rival, Sparta, which created a golden age of peace in the city.

During his involvement in politics, Pericles continued to support the arts. Around 447 bce he also began to show a strong interest in building and architecture. He oversaw the construction of the Parthenon, which he envisioned as a monument to the power of Athens. The Parthenon was built on the central fortified hill of the city, the Acropolis.

Pericles was eventually driven from office by political enemies, but was reelected the city's military commander in 428 bce. He died shortly thereafter.

Anaxagoras was not the last of the great philosophers of ancient Greece to be accused of not believing in the gods. Socrates was also tried for this offense and put to death. Aristotle was accused of the same crime, but fled from Athens, saying he refused to allow the Athenians to sin against philosophy a third time.

Effects on thought

Anaxagoras's work had a significant effect on philosophy and thought. His theory of nous proved an inspiration for Socrates, though the latter was sorry Anaxagoras had not taken his argument further. For Socrates, nous seemed to be simply a mechanical means of organizing the universe, a force without morality or goal. Socrates believed there was more than this to the universe. Nevertheless, Anaxagoras's theory of creation is historically important because some of its aspects were adopted by later scientists. These include his theory of the rotating cosmic mass at the beginning of time and his idea that the basic building blocks of life could be divided.

More importantly, by attempting to explain the process of creation without relying on gods as the driving factor, Anaxagoras helped to pave the way for criticism of religious ideas about the origin of the universe. His explanation of the formation of heavenly bodies such as the sun, stars, and the moon ultimately led to doubts in God's existence (agnosticism) or possibly even a complete lack of belief in God or gods (atheism). Some historians, however, call Anaxagoras the father of theism, the belief in a personal god that created the universe, or even of monotheism, the belief in one supreme being. Although it was never referred to as a god, the nous Anaxagoras believed in was the thing that set the early cosmos in motion and organized life. This was taken by some to mean that Anaxagoras's theory focused on one power or force in the universe, rather than a pantheon, or group, of gods as the Greeks had believed. Therefore, the father of agnosticism or atheism is sometimes also called the father of monotheism.

For More Information

BOOKS

Fairbanks, Arthur, ed. and trans. The First Philosophers of Greece. London, England: K. Paul, Trench, Trubner, 1898.

Gershenson, Daniel E., and Daniel E. Greenberg. Anaxagoras and the Birth of Physics. Waltham, MA: Blaisdell Publishing Co., 1964.

Kirk, G. S., and J. E. Raven. The Presocratic Philosophers: A Critical History with a Selection of Texts. Cambridge, England: Cambridge University Press, 1983.

Schofield, Malcolm. An Essay on Anaxagoras. New York, NY: Cambridge University Press, 1980.

PERIODICALS

Davison, J. A. "Protagoras, Democritus, and Anaxagoras." Classical Quarterly (July-September 1953): 33-45.

Kingsley, Peter. "Notes on Air: Four Questions of Meaning in Empedocles and Anaxagoras." Classical Quarterly (January-June 1995): 26-29.

WEB SITES

"Anaxagoras." Atlantic Baptist University. http://www.abu.nb.ca/Courses/GrPhil/Anaxagoras.htm (accessed on May 24, 2006).

"Anaxagoras of Clazomenae." Turnbull School of Mathematical and Computational Sciences. http://www-groups.dcs.st-and.ac.uk/∼history/Mathematicians/Anaxagoras.html (accessed on May 24, 2006).

Fairbanks, Arthur. "Anaxagoras Fragments and Commentary." Hanover Historical Texts Project. http://history.hanover.edu/texts/presoc/anaxagor.htm (accessed on May 24, 2006).

"Pericles." PBS.org. http://www.pbs.org/empires/thegreeks/htmlver/characters/f_pericles.html (accessed on May 24, 2006).

ANAXAGORAS

Greek philosopher; b. Clazomenae in Asia Minor, c. 500 b.c.; d. Lampsacus in Ionia, c. 428 b.c. As a young man, he was probably acquainted with the work of Anaximenes. During the Persian invasion of Ionia, he settled at Athens, where he engaged in scientific inquiry, wrote, and taught such personages as Pericles and Euripedes. He appears to have been the first thinker to bring the scientifico-philosophical spirit from Ionia to Athens. He was celebrated for his astronomical investigations, especially his discovery of the true cause of eclipses, and respected for his high moral character. In middle life, after 30 years at Athens, he was indicted by Pericles's political foes on a charge of impiety, namely, claiming the sun was but an incandescent stone. Through the persuasive influence of Pericles, he was released. However, having been compelled to leave Athens, he retired to Lampsacus, a Milesian colony, where he may have founded a school.

Teaching. Anaxagoras most likely wrote only one book, probably under the customary title On Nature. It was composed in an attractive and lofty style and was sold at Athens for one drachma during the time of Socrates's trial. From a critical examination and interpretation of the extant fragments, a rather self–consistent cosmological system can be constructed.

In his study of the physical universe, Anaxagoras was confronted with two interrelated problems: stability and change, unity and plurality. Among his predecessors and contemporaries, the Milesians, Pythagoreans, and heraclitus emphasized becoming and multiplicity, whereas parmenides, zeno of elea, and Melissus stressed permanency and oneness. Anaxagoras attempted to bridge the gulf between these extremes with a compromise solution.

Stability and Change. In his explanation of the special qualities of individual things, Anaxagoras assumed the existence of as many original qualitative principles as there are qualitative determinations in perceptible things. On the empirical ground of innumerable phenomena, he pluralized the Parmenidean being into an unlimited number of seeds (H. Diels, Die Fragmente der Vorsokratiker. Griechisch und Deutsch 4 59A). Each seed is infinitesimal, infinitely divisible, eternal, qualitatively unchangeable, stable, and homogeneous, for this simple principle, however much it is divided, always separates into parts qualitatively the same as its whole; accordingly, Aristotle called them "ὁμοιομερ[symbol omitted]" or "like things" (Phys. 187a 25). Agreeing with Parmenides that coming-to-be and ceasing-to-be are only apparent, Anaxagoras explained the generation and corruption of complex things as simply the mixing and unmixing of seeds (Fragmente 17).

Unity and Plurality. Anaxagoras's account of unity and plurality logically develops from his theory of stability and change in accordance with Parmenides's two canons: the exclusion of real change and the impossibility of deriving plurality from unity. Anaxagoras reasoned that the manifold different sense objects can be adequately explained only by a plurality of originally different seeds, each a qualitative unit. Although all the primordial seeds—e.g., flesh, bone, and hair—are mixed in individual things, there being "a portion of everything in everything" (Fragmente 6), yet each complex thing is (and is called) whatever preponderates. Anaxagoras theorized that in the far distant past all the seeds co-existed in the unity of a primeval agglomerate, and that, through the powerful forces of vortex motion, they were separated and then organized to form the present visible cosmos (Fragmente 2, 9, 15).

Mind. Although the seeds are movable in space, they are not in motion of themselves. Rather they require an ultimate, universal principle of their orderly movement— Nous or Mind (Fragmente 12, 13). Alone in motion of itself, Mind communicates orderly movement to the seeds, separating them from the pristine conglomerate. Mind is no less illimitable than the chaotic congeries. Like the seeds, it is eternal (Fragmente 14); simple, "mixed with no thing" (Fragmente 12), homogeneous; quantitatively divisible, yet qualitatively unchangeable; participated by some things, yet remaining essentially identical with itself. Unlike other things, however, Mind is the finest and purest being; it is independent, since it is self-ruling and self-moving, the first principle of motion and order in the cosmos, with "complete understanding of everything" and it "has the greatest power" (Fragmente 12).

Influence and Critique. Anaxagoras's conception of Mind represents a major contribution in the history of philosophy. For his supreme psychophysical principle, transcendent being of beings and unifying cause of all becoming, he was justly commended by aristotle as "a sober man in contrast with the random talk of his predecessors" (Meta. 984b 15–18). Both plato (Phadeo 98) and Aristotle (ibid. 985a 18), however, criticized Anaxagoras for failing to go beyond the function of Mind as the initiator of cosmic motion to its subsequent causal influence in the production of natural phenomena. Once Mind originates movement, its causality—somewhat suggestive of teleology—becomes less direct and rather obscure, and then purely mechanical factors seem to assume hegemony.

Nevertheless, in Anaxagoras's thought there is the emergence of a dualism between Mind and nonmental reality. Although Mind is still conceived as something material, it is a distinct, independent, universal, primary cause of orderly motion in the cosmos. This notion is given a central role and greatly enriched in the natural theology of subsequent Greek and Christian philosophers.

Bibliography: k. freeman, The Pre-Socratic Philosophers: A Companion to Diels, Fragmente der Vorsokratiker (2d ed. Cambridge, Mass. 1959); Ancilla to the Pre-Socratic Philosophers (Cambridge, Mass. 1957). g. s. kirk and j. e. raven, The Pre-Socratic Philosophers: A Critical History with a Selection of Texts in Greek and English (Cambridge, Eng. 1957). j. burnet, Early Greek Philosophy (4th ed. London 1930; reprint 1957). w. w. jaeger, The Theology of the Early Greek Philosophers, tr. e. s. robinson (Oxford 1960). j. owens, A History of Ancient Western Philosophy (New York 1959). f.c. copleston, History of Philosopy (Westminster, MD 1946—) 1:66–71.

[p. j. aspell]

Anaxagoras

The Greek philosopher Anaxagoras (ca. 500-ca. 428 B.C.) was the first to formulate a molecular theory of matter and to regard the physical universe as subject to the rule of rationality or reason.

Anaxagoras was born on the Ionian coast of Asia Minor in the town of Clazomenae, near Smyrna (now Izmir, Turkey). Nothing is known about his life before the age of 20, when he began to study philosophy. About 462 he moved to Athens, which was rapidly becoming an attractive cultural center. Anaxagoras was the first philosopher to take up residence in Athens. His teachings influenced the playwright Euripides, but his most famous pupil was Pericles, who dominated the political life of Athens during the 30 years Anaxagoras lived there.

Anaxagoras did not believe that the sun and moon were divinities, as the Greeks did, and he was prosecuted for his teachings. He returned to Asia Minor to a town allied with Athens, Lampsacus (now Lapseki, Turkey). Here he was treated with respect, and his memory was still honored a century after his death.

"About Nature"

Anaxagoras's views are preserved only in excerpts and summaries, more or less authentic. His book, written in prose, was entitled About Nature. It started with this assertion: "All things were together, infinite in number." This abrupt beginning was intended as a blunt contradiction of an earlier contention that the universe was "one continuous whole, which was not in the past," there being only an everlasting unchanging present. In direct opposition to this perpetually static monism, Anaxagoras propounded a constantly changing pluralism. He was the first philosopher to declare the number of separate things to be infinite (the universe as a whole having already been described as infinite).

Each of Anaxagoras's infinitely numerous separate things could be divided and further subdivided endlessly. All the things that were together were infinite not only in number but also in smallness: "Of what is small, there is no smallest part, but always a smaller." By contrast with the thinkers who maintained that matter consisted of those smallest units which were the atoms or indivisible particles, Anaxagoras believed in the infinite divisibility of matter. Nevertheless, as often as this process of subdivision was repeated, the resulting product always emerged as a unit of matter, however infinitesimally small it might be. In this sense Anaxagoras may be regarded as the author of the first molecular theory of matter.

Concept of Mind

His infinitely divisible things, infinite in number, were originally all together. How they had come together and where they had come from were questions not propounded by Anaxagoras. Thus, his universe began with a vast indiscriminate jumble or species of magma, which in the course of time was set whirling by Mind: "The whole rotation was controlled by Mind in such a way that in the beginning there was a vortical motion. At first the turning began on a small scale, but it spins more widely and it will spin even more widely."

What is more, Anaxagoras's Mind itself was not an insubstantial, incorporeal, exclusively mental, spiritual, or divine entity. Unlike a theist, Anaxagoras described his cosmic Mind as being the "most delicate and purest of all things." Nor was Anaxagoras a dualist in the conventional sense of one who counterposes mind against matter, for he declared that "Mind even now is where all other things are too, in the surrounding plenitude as well as in the things that have been assembled and those that have been disassembled."

Anaxagoras rebuked "the Greeks for not thinking correctly about birth and death, since nothing is born or dies; on the contrary, everything is assembled out of existing things and then dissolved. Accordingly, the Greeks would properly call birth 'combination' and death 'dissociation."' In other words, any individual thing comes into being by combining preexisting components and is dissolved into its constituent parts when its existence is terminated. While individuals come and go, the building blocks or molecular particles persist. They move about freely and enter into new combinations without undergoing any change in their essential nature.

This unceasing flux of migration, combination, dissolution, and recombination is not senseless or chaotic. For Anaxagoras, cosmic Mind "is infinite and absolute; it possesses perfect knowledge of everything, exerts the greatest power, and dominates all living things, the biggest and the smallest." Since all life in Anaxagoras's universe is under the control of Mind, each molecular interchange occurs according to rule. His universe therefore is thoroughly rational, and what he called "Mind" is analogous to what was afterward termed the "laws of nature."

Split-Level Universe

To this overall vision of an orderly cosmos, Anaxagoras contributed some valuable details. Of these, unquestionably the most spectacular was his discovery that the moon does not shine by its own light. By contrast, in the Hebrew Bible the moon was the lesser of the two great lights; like the sun, which was the biblical greater light, the Hebrew moon was self-luminous. Presumably it is because the earth too receives light from the sun that Anaxagoras declared the moon to be earth. His earth and moon resembled each other also in having "flat areas and depressions." Anaxagoras's amazingly prescient description of the moon's ups and downs and his implicit denial that the lunar surface was perfectly spherical waited more than 2,000 years for visual confirmation by Galileo's telescope, and then more than 3 additional centuries for the direct physical proof provided by the American astronauts on the moon.

Anaxagoras believed (mistakenly) that the sun was a red-hot stone. Apparently generalizing from the instances of the sun and moon, he asserted that all the heavenly bodies were stone. His opinion that rock was the material of those bodies may have been inspired by the fall of a huge meteorite, said to have been as big as a wagon, near the Dardanelles when he was a young man. Since Anaxagoras correctly classified the meteorite as an object fallen from the sky to the earth, his universe was all alike. Later the cosmos was divided into an ethereal heaven, reserved for divinities, and the coarse earth, to which mere mortals were consigned. The painful process of reunifying this post-Anaxagorean split-level universe amounted to a return to the one world of Anaxagoras.

Further Reading

Daniel E. Gershenson and Daniel A. Greenberg, Anaxagoras and the Birth of Physics (1964), is a collection of the ancient references to Anaxagoras, arranged in chronological order and analyzed as to content; the bibliography is annotated. Also useful is Felix M. Cleve, The Philosophy of Anaxagoras (1949). Among the general books on early Greek philosophy that discuss Anaxagoras are John Burnet, Early Greek Philosophy (1892; 4th ed. 1930); Theodor Gomperz, Greek Thinkers: A History of Ancient Philosophy (3 vols., 1896-1909; trans., 4 vols., 1901-1912); and G. S. Kirk and J. E. Raven, The Presocratic Philosophers: A Critical History with a Selection of Texts (1962).

Additional Sources

Schofield, Malcolm., An essay on Anaxagoras, Cambridge Eng.; New York: Cambridge University Press, 1980.

Anaxagoras., The fragments of Anaxagoras, Meisenheim am Glan: Hain, 1981. □

Anaxagoras

(b. Clazomenae, Lydia, 500 B.C.[?]; d. Lampsacus, Mysia, 428 b.c.[?])

natural philosophy.

Although he was born of wealthy parents, Anaxagoras neglected his inheritance to devote himself to natural philosophy. At the age of twenty, he traveled to Athens, where he spent the next thirty years. There he became a friend of Pericles and brought Ionian physical speculation to Athens at the height of its intellectual development. Subsequently he was prosecuted for impiety and banished¹ because, it was alleged, he held the sun to be a mass of red-hot stone. This charge doubtless was instigated by the political opponents of Pericles, who sought to attack him through his friendship with an atheistic scientist. Anaxagoras wrote only one treatise, completed after 467 b.c.

Like Empedocles, Anaxagoras sought to reconcile Parmenides’ logic with the phenomena of multiplicity and change. Each maintained that there was never a unity in either the qualitative or the quantitative sense and postulated instead a plurality of eternal, qualitatively different substances that filled the whole of space. They accepted Parmenides’ negation of coming-into-being and passing-away but replaced the former with the aggregation of their indestructible elements and the latter with their segregation. Motive forces were introduced to account for motion—a phenomenon whose validity had, prior to Parmenides, been taken for granted.

Anaxagoras evidently did not consider that Empedocles had fully satisfied the demands of Eleatic logic.² Empedocles had seen no objection to making secondary substances come into being as various combinations of his elements. A piece of flesh, according to him, consisted of the four elements juxtaposed in almost equal quantities. Theoretically, if it were divided, one would arrive at a minimum piece of flesh and thereafter at particles of the constituent elements. Thus, flesh originally came into being from the elements and, strictly speaking, from what is not flesh. Anaxagoras’ own formulation of the problem is preserved: “How,” he asks, “could hair come to be from what is not hair and flesh from what is not flesh?” (Diels and Kranz, B10). His answer was to claim that everything preexisted in our food. Thus, he denied the existence of elements simpler than and prior to common natural substances and maintained that every natural substance must itself be elementary, since it cannot arise from what is not itself. Furthermore, to avoid being confuted by Zeno’s paradoxes against plurality, he held that matter was infinitely divisible; that however far any piece of matter might be divided, there always resulted smaller parts of the same substance, each of which always contained portions of every other substance³ and was itself capable of further division. Its predominant ingredients were responsible for its most distinctive features.

Initially, Anaxagoras held, all things were together in an apparently uniform, motionless mixture. Then Mind (Nov̂s) instituted a vortex, causing the dense, wet, cold, and dark matter to settle at the center and the rare, hot, and dry matter to take up peripheral positions as the sky. From the former, the disklike earth was compacted (Diels and Kranz, B15–16). The sun, moon, and stars, however, were torn from the earth and carried around, ignited by friction.⁴

Although strikingly rational, Anaxagoras’ astronomy was not fruitful because it provided no stimulus to discover the laws of planetary motion. A more important contribution was his concept of a separate, immaterial moving cause, which paved the way for a fully teleological view of nature.⁵ His theory of matter, however, was not influential, doubtless as much because of its subtlety and sophistication as because of its lack of economy.

NOTES

1. For the chronology of Anaxagoras’ life see Taylor, Davison, and Guthrie.

2. For the relative dating of the works of these two see Longrigg, p. 173, n. 49.

3. The interpretation of Anaxagoras’ theory is highly controversial. Certain scholars, most cogently Vlastos, reject this so-called naïve interpretation on the grounds that it involves a redundancy and an infinite regress. Their solution, although plausible, is, however, less in accordance with the fragments. On the question of the regress see especially Strang, pp. 101 ff.

4. The fall of the meteorite at Aegospotami in 467 b.c. probably suggested this theory. (It might be observed here that although Anaxagoras is commonly stated to have been the first to discover the true explanation of eclipses, there is evidence against his priority.)

5. For the reaction of Plato and Aristotle see Phaedo 97B and Metaphysics 985a 18 ff. (Diels and Kranz, A47).

BIBLIOGRAPHY

The collected fragments and later testimony are in H. Diels and W. Kranz, Die Fragmente der Vorsokratiker, 6th ed. (Berlin, 1951–1952), II, 5–44.

Secondary literature includes C. Bailey, The GreekAtomists and Epicurus (Oxford, 1928), pp. 537–556; D. Bargrave–Weaver, “The Cosmogony of Anaxagoras,” in Phronesis, 4 no. 2 (1959), 77–91: J. Burnet, Early, Greek Philosophy, 4th ed. (London, 1930), pp. 251–275; W. Capelle, “Anaxagoras,” in Neue Jahrbücher für das klassische Altertum (1919), 81–102, 169–198; F. M. Cleve, The Philosophy of Anaxagoras (New York, 1949); F. M. Corn–ford, “Anaxagoras’ Theory of Matter,” in Classical Quarterly, 24 (1930), 14–30, 83–95; J. A. Davison, “Protagoras, Democritus and Anaxagoras,” ibid., n.s. 3 (1953), 33–45; O. Gigon, “Zu Anaxagoras,” in Phiologus, 91 (1936–1937), 1–41; W. K. C. Guthrie, A History, of Greek Philosophy. II (Cambridge, England, 1965), 266–338; G. S. Kirk and J. E. Raven, The Presocratic Philosophers (Cambridge, England, 1957), pp. 362–394; J. Longrigg, “Philosophy and Medicine: Some Early Interactions,” in Harvard Studies in Classical Philology, 67 (1963), 147–175; R. Mathewson, “Aristotle and Anaxagoras: An Examination of F. M. Cornford’s Interpretation,” in Classical Quarterly, n.s. 8 (1958), 67–81; C. Mugler, “Le problème d’Anaxagore,” in Revue des ètudes grecques, 69 (1956), 314–376; A. L. Peck, “Anaxagoras: Predication as a Problem in Physics,” in Classical Quarterly, 25 (1931), 27–37, 112–120: J. E. Raven, “The Basis of Anaxagoras’ Cosmogony,” ibid., n.s. 4 (1954), 123–137; C. Strang, “The Physical Theory of Anaxagoras,” in Archiv Für Geschichte der Philosophic, 45 , 2 (1963), 101–118; P. Tannery, Pour l’historie de la science hellène, 2nd ed. (Paris, 1930), pp. 275–303; A. E. Taylor, “On the Date of the Trial of Anaxagoras,” in Classical Quarterly, 11 (1917), 81–87; G. Vlastos, “The Physical Theory of Anaxagoras,” in Philosophical Review, 59 (1950), 31–57; and M. L. West, “Anaxagoras and the Meteorite of 467 b.c.,” in Journal of the British Astronomical Association, 70 (1960), 368–369.

James Longrigg

Anaxagoras

Circa 500-Circa 428 b.c.e.

Astronomer and philosopher

Sources

Modern Ideas . Anaxagoras was born in Clazomenae, Anatolia (in presentday Turkey). Around 480 b.c.e. he moved to Athens, where he lived for thirty years and taught a variety of students, including Pericles and possibly Socrates. Unfortunately, few of the writings of Anaxagoras have survived. When he declared that the Sun was an incandescent stone, he was prosecuted for impiety, although the charge was more a political attack on Pericles. He then went into exile and spent his last years at Lampsacus.

Cosmology. Aside from discovering the true cause of eclipses, Anaxagoras made some interesting assertions concerning the physical universe. He declared that natural objects are composed of infinitesimally small particles containing mixtures of all qualities. Accordingly, the nous (mind, reason, or intelligence) acts upon masses of these particles to produce objects. It seemed to him quite impossible that anything should come into being from what does not exist. For example, when ingested, simple and homogeneous nourishment such as bread or water helps produce hair, veins, arteries, sinews, bones, skin, and all the other parts of the human body.

Sources

Felix M. Cleve, The Philosophy of Anaxagoras: An Attempt at Reconstruction (New York: King’s Cross Press, 1949).

Geoffrey Stephen Kirk and John Earle Raven, eds., The Presocratic Philosophers: A Critical History with a Selection of Texts (Cambridge: Cambridge University Press, 1957).