Anaxagoras of Clazomenae
Anaxagoras (Greek: Ἀναξαγόρας, Anaxagoras, "lord of the assembly"; c. 500 BC – 428 BC) was a Pre-SocraticGreek philosopher. Born in Clazomenae in Asia Minor, Anaxagoras was the first philosopher to bring philosophy from Ionia to Athens. He attempted to give a scientific account of eclipses, meteors, rainbows, and the sun, which he described as a fiery mass larger than the Peloponnese. According to Diogenes Laertius and Plutarch he fled to Lampsacus due to a backlash against his pupil Pericles.
Anaxagoras is famous for introducing the cosmological concept of Nous (mind), as an ordering force. He regarded material substance as an infinite multitude of imperishable primary elements, referring all generation and disappearance to mixture and separation respectively.
Anaxagoras is famous for introducing the cosmological concept of Nous (mind), as an ordering force. He regarded material substance as an infinite multitude of imperishable primary elements, referring all generation and disappearance to mixture and separation respectively.
Biography
- Anaxagoras appears to have had some amount of property and prospects of political influence in his native town of Clazomenae in Asia Minor. However, he supposedly surrendered both of these out of a fear that they would hinder his search for knowledge. Valerius Maximus preserves a different tradition: Anaxagoras, coming home from a long voyage, found his property in ruin, and said: "If this had not perished, I would have." "This is a sentence - says the Roman - denoting the most perfect wisdom". Although a Greek, he may have been a soldier of the Persian army when Clazomenae was suppressed during the Ionian Revolt.
- In early manhood (c. 464–461 BC) he went to Athens, which was rapidly becoming the centre of Greek culture. There he is said to have remained for thirty years. Pericles learned to love and admire him, and the poet Euripides derived from him an enthusiasm for science and humanity.
Anaxagoras brought philosophy and the spirit of scientific inquiry from Ionia to Athens. His observations of the celestial bodies and the fall of meteorites led him to form new theories of the universal order. - He attempted to give a scientific account of eclipses, meteors, rainbows, and the sun, which he described as a mass of blazing metal, larger than the Peloponnese. He was the first to explain that the moon shines due to reflected light from the sun. He also said that the moon had mountains and he believed that it was inhabited.
- The heavenly bodies, he asserted, were masses of stone torn from the earth and ignited by rapid rotation. He explained that though both sun and the stars were fiery stones, we do not feel the heat of the stars because of their enormous distance from earth. He thought that the earth is flat and floats supported by 'strong' air under it and disturbances in this air sometimes causes earthquakes.
These speculations made him vulnerable in Athens to a charge of impiety. Diogenes Laertius reports the story that he was prosecuted by Cleon for impiety, but Plutarch says that Pericles sent Anaxagoras to Lampsacus for his own safety after the Athenians began to blame him for the Peloponnesian war.
About 450 BC, according to Laertius, Pericles spoke in defense of Anaxagoras at his trial. Even so Anaxagoras was forced to retire from Athens to Lampsacus in Troad (c. 434–433 BC). He died there in around the year 428 BC. Citizens of Lampsacus erected an altar to Mind and Truth in his memory, and observed the anniversary of his death for many years.
Anaxagoras wrote a book of philosophy, but only fragments of the first part of this have survived, through preservation in work of Simplicius of Cilicia in the sixth century AD.
His contributions
- Squaring the circle is a problem proposed by ancient geometers. It is the challenge of constructing a square with the same area as a given circle by using only a finite number of steps with compass and straightedge.
- More abstractly and more precisely, it may be taken to ask whether specified axioms of Euclidean geometry concerning the existence of lines and circles entail the existence of such a square.
In 1882, the task was proven to be impossible, as a consequence of the Lindemann–Weierstrass theorem which proves that pi (π) is a transcendental, rather than an algebraic irrational number; that is, it is not the root of any polynomial with rational coefficients. It had been known for some decades before then that if pi were transcendental then the construction would be impossible, but that pi is transcendental was not proven until 1882. Approximate squaring to any given non-perfect accuracy, in contrast, is possible in a finite number of steps, since there are rational numbers arbitrarily close to pi. - The expression "squaring the circle" is sometimes used as a metaphor for doing something logically or intuitively impossible.