Anaxagoras

Philosopher and scientist

Born: c. 500 b. c.e.; Clazomenae, Anatolia (now in Turkey) Died: c. 428 b. c.e.; Lampsacus (now Lapseki, Turkey) Category: Philosophy; science and technology

Life Virtually nothing is known about the parents of Anaxagoras (an-aks-AG-ur-uhs) or about his childhood, adolescence, or education. Born into a wealthy family in an Ionian Greek city, he moved to Athens as a young man and became friends with the young Pericles, who apparently influenced him considerably.

Sometime in or shortly after 467 b. c.e. Anaxagoras published his only written work, apparently titled Nature. Of this work, only seventeen fragments totaling around twelve hundred words have survived, all recorded as quotations in the works of later generations of philosophers. Anaxagoras’s book was an ambitious attempt to explain the origins and nature of the universe without recourse (or so it seemed to many of his contemporaries) to any supernatural agents. Other Ionian philosophers, notably Parmenides, had preceded Anaxagoras in this endeavor, but their systems were logically unable to explain the multiplicity of “things” in the universe or to explain physical and biological change in those things because they had postulated that all things are made from the same basic “stuff.” Anaxagoras overcame the logical inconsistencies of this argument by postulating an infinite variety of substances that make up the whole of the universe.

Anaxagoras argued that there is something ofeverything in everything. By this he meant that, for example, water contains a part of every other thing in the universe, from blood to rock to air. The reason that it is perceived to be water is that most ofits parts are water. In the beginning, according to the first fragment of Anaxagoras’s book, infinitely small parts of everything in equal proportions were together in a sort of primal soup. In fragment 3, he proposes a primitive version of the law of the conservation of energy, by saying that anything, no matter how small, can be divided infinitely, because it is not possible for something to become nonexistent

Anaxagoras.

Through dividing. This idea of infinite divisibility is unique to the Anaxa-gorean system; no philosopher before or since has proposed it.

This universal mixture of all things acquired form and substance, according to fragment 12, through the actions of nous, or “mind.” Mind, Anaxagoras argues, is not part of everything (though it is a part of some things), nor is a part of everything found in mind (though parts of some things are found in mind). Mind set the primal soup into rotation, and the different things began to “separate off,” thus forming the universe. The rotation of the primal mixture not only separated everything according to its kind (but not perfectly, as everything still contains parts of every other thing) but also supplied heat, through friction. Among other things, friction ignited the Sun and the stars. Considerable disagreement over the exact meaning Anaxagoras was trying to convey with the term “mind” has colored scholarly works on his book since Aristotle and continues to be a controversial issue.

Anaxagoras’s system not only enabled him and his students to describe all existing objects, but it also permitted the explanation of physical and biological change. It was the introduction of the idea of mind and its action as a formative agent in the creation of the universe for which Anaxagoras became famous and that rejuvenated Socrates’ interest and faith in philosophy.

One of Anaxagoras’s most notable achievements during his stay in Athens was his postulation of the correct explanation for a solar eclipse. Anaxagoras was apparently the first to argue that an eclipse occurs when the Moon (which he said was a large mass of cold rocks) passes between the Earth and the Sun (which he said was a larger mass of hot rocks). He may have reached this conclusion after the fall of a large meteorite near Aegy-potomi in 467 b. c.e., which excited wide discussion throughout the Hellenic world.

Sometime after 467, Anaxagoras was accused of and tried for impiety (denying the gods), after admitting that he thought the Sun was a huge mass of “hot rock,” and Medism (sympathizing with the Persians). The actual date of his trial and subsequent banishment from Athens is still hotly debated among classical scholars. Several scholars have concluded that Anaxagoras’s trial was engineered by Pericles’ political rivals, in order to deprive Pericles of a trusted friend. Convicted of impiety Anaxagoras went into exile. Anaxagoras spent his remaining years as the head of a flourishing school at Lampsacus, where many young Greeks came to study with him before his death, probably in 428 b. c.e.

Influence The thesis that Anaxagoras greatly influenced Socrates and Aristotle is easily proved by their elaborate discussions of his system in their own words. Through those two most influential of all Greek thinkers, he has had a profound impact on all subsequent generations of philosophers and natural scientists in the Western world. Some of Anaxagoras’s critics, both ancient and modern, accuse him of merely substituting the word “mind” for “God” or “the gods.” Thus, in their estimation, his philosophy becomes merely a humanistic religion. Other critics have dismissed Anaxagoras’s teachings as simplistic and unworthy of serious consideration. His supporters, from Aristotle to the present, have defended him as a pioneering thinker who provided much of the inspiration for the flowering of post-Socratic philosophy during the Golden Age of Greece and the Hellenistic world.

Further Reading

Barnes, Jonathan. The PresocraticPhilosophers. London: Routledge, 1999. Brunschwig, Jacques, and G. E. R. Lloyd, eds. Greek Thought: A Guide to

Classical Knowledge. Cambridge, Mass.: Belknap Press of Harvard University Press, 2000.

Davison, J. A. “Protagoras, Democritus, and Anaxagoras.” Classical Quarterly 3 (1953): 33-45.

Gershenson, Daniel E., and Daniel A. Greenberg. Anaxagoras and the Birth of Physics. New York: Blaisdell, 1964.

Guthrie, W. K. C. A History of Greek Philosophy. Vol. 2. Cambridge, England: Cambridge University Press, 1965.

Kirk, Geoffrey S., John E. Raven, and M. Schofield. The Presocratic Philosophers. 2d ed. New York: Cambridge University Press, 1983.

Mansfield, J. “The Chronology of Anaxagoras’s Athenian Period and the Date of His Trial.”Mnemosyne 33 (1980): 17-95.

Matthews, Gareth B. “On the Idea of There Being Something of Everything in Everything.” Analysis 62, no. 1 (January, 2002): 1.

Mourelatos, Alexander P. D. The Pre-Socratics: A Collection of Critical Essays. Princeton, N. J.: Princeton University Press, 1993.

Schofield, Malcolm. An Essay on Anaxagoras. Cambridge, England: Cambridge University Press, 1980.

Paul Madden

See also: Cosmology; Pericles; Philosophy; Pre-Socratic Philosophers;

Science; Socrates.