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2500 years ago the philosopher Anaxagoras brought the spirit of science to Athens

The philosopher Anaxagoras introduced “the scientific spirit” to Athens 2,500 years ago and planted the seeds of a philosophical tradition that led to Socrates, Plato and Aristotle.


No one seems to have noticed, but 2021 marks a pretty important anniversary in the history of science and Western civilization.

This year marks 2,500 years since a philosopher named Anaxagoras arrived in Athens, Greece. Nobody held a party at the time. But it was nonetheless an important historical and intellectual landmark.

Before Anaxagoras, ancient Greek science (or to be less anachronistic, natural philosophy) was actually not much practiced in Greece itself. Natural philosophy originated in the early sixth century BC.

at the Greek settlement of Miletus in Ionia, the west coast of present-day Turkey. A second branch of original Greek science soon took root in southern Italy after an Ionian, a math fan named Pythagoras, moved there.

Born in the Ionian city of Clazomenae, Anaxagoras was the first natural philosopher to live in Athens and

promote the Ionian philosophical view there. As the science historian George Sar ton wrote, Anaxagoras “introduced the scientific spirit to Athens.

” Soon after, Athens became the center of philosophical research of the Western world, when the triumvirate of Socrates, Plato, and then Aristotle established philosophy as an essential part of a civilized intellectual discourse.

To be fair, there is some doubt about the exact date of the move from Anaxagoras to Athens. But the biographer of philosophers Diogenes Laertius wrote that Anaxagoras started doing philosophy in Athens at the age of 20, and says he was 20 years old when the Persian king Xerxes attacked Greece – which was 480 BC, 2,500 years ago. 

(You might think 2021 would make that 2,501 years ago, but only if you forget that there was no year 0, so you have to subtract a year from the calculation.)

It is possible that Anaxagoras met young Socrates during his stay in Athens, but the direct link with Socrates and his philosophical descendants was through the philosopher Archelaus.

Anaxagoras “was the first to encourage Archelaus the Athenian to practice philosophy,” wrote the renowned physician Galen. And Archelaus was Socrates’ teacher, who taught Plato, who taught Aristotle, whose influence dominated science for two millennia.

Anaxagoras came about a century after the first Ionian philosophers, Thales of Miletus and his younger Milesian contemporary Anaximander. Together with a third Milesian, Anaximenes, they had developed a new way of looking at the natural world.

They looked for explanations for phenomena in natural causes, rather than attributing them to the behavior of mythological gods invented by poets to explain cosmic history.

The lightning was no longer a sign of an angry Zeus, Anaximander explained – rather it flashed when the clouds were disturbed by the wind. Although the original Milesians did not agree on all issues, they all insisted that natural philosophy should be based on an underlying foundation (called the arche or arkhé), a principle from which all of reality could be derived.

“The concepts of beginning, origin, guiding principle, and cause were closely united in the one word arche,” wrote philosopher-historian William Guthrie. Thales thought the fundamental principle was water; Anaximenes said air.

Anaximander thought that everything sprang from a mysterious material called apeiron, which means something like the unlimited or the boundless. In Italy, the Pythagoreans promoted the idea that the underlying basis of everything was number.

For Anaxagoras, the arche was nous, or “mind” (sometimes translated as “intellect” or “intelligence”).His approach expanded the scientific ideas of his Ionian predecessors to address issues of the Italian philosopher Parmenides.

Everything always had to be as it is, Parmenides reasoned, because nothing could arise from nothing – non-existence cannot produce existence, because there is no such thing as non-existence, by definition of existence.

Reality consisted of an ever-present, unchanging, unshakable mass of undifferentiated equality that filled all of space, Parmenides concluded. There was therefore no room for any movement or change – the world perceived by the senses was false, an illusion that concealed the true nature of reality.

Senses offered a “way of appearing”; only reason provided the “way of truth”. While it sounds crazy to modern ears, it was a difficult argument to disprove at the time. But Anaxagoras had a refined and subtle mind; in response to Parmenides, he introduced an entirely new idea of ​​fundamental reality, claiming that all different kinds of matter are already present in a particular piece of matter.

No new thing has to “come into being,” because all possible things already exist to begin with and persist in everything – even if it is too small in quantities for the senses to detect. For example, a lump of so-called pure gold also contains tiny “seeds” of any other kind of matter.

Our senses are just too crude to notice the seeds. (Incidentally, the seeds themselves also contain smaller amounts of everything. Anaxagoras had invented the idea of ​​infinite divisibility, another new thought.

Each piece of matter can appear to turn into something else as a result of shifts in the relative amounts of its seeds. For example, eating vegetables can produce meat and bone in your body because the digestive process concentrated the meat and bone seeds that were imperceptibly diffused in the original food.

Initially all matter was one big static mass. At some point in the past, nous or spirit put that mass in a whirling motion, concentrating heavy things (like earth) in the center, creating the earth. Chunks of earth swirled out and became stars and the sun and the moon. The nous of Anaxagoras was the only distinctive ingredient in its system.

Other things were all mixed in with everything else. But the mind was its own thing. “Mind is something infinite and independent and is mixed with nothing,” he wrote. But the spirit (while retaining its purity) is present in many things, including all humans, called by Anaxagoras “the wisest of the beasts.

” (Guthrie says that when asked why some people don’t seem so wise, “Anaxagoras would have commented that while all men have intellect, they don’t always use it.”)

Despite his own considerable intellect, Anaxagoras’s theory of matter was wrong. But its reputation rests on many other contributions to scientific thinking. A century ago, Thomas Heath, the eminent scholar of Greek science and mathematics, declared that Anaxagoras was “a great man of science” who “enriched astronomy with a groundbreaking discovery”: that the light of the moon is not his, but a reflection of light from the sun.

(Some scholars say he got the idea from Parmenides, but at least it is still very worthwhile that a crater near the moon’s north pole is called Anaxagoras.) Anaxagoras wrote a paper on many other scientific topics, including meteorology. and geology.

He presumably predicted that a stone could fall to the earth from the sky; in any case, he received credit for such a prediction when in 467 BC. a meteorite fell in Thrace (now Turkey). However, he argued that the Earth was flat. And that it was supported in space by the sky below, echoing its Ionian predecessor Anaximenes.

However, the scientific importance of Anaxagoras rests not on the rigor of his theories, but rather on the insight of his attitude. He expressed a scientific attitude in which he renounced the supernatural more clearly than his predecessors. Even Thales felt that “there were gods in all things,” Aristotle had written, and Thales and others had attributed souls to celestial bodies.

There is no sign from his known writings that Anaxagoras’ nous was in any way religious – it was a natural part of the cosmos and directed it, just as the human spirit prompts a human body to move its limbs. “Nowhere in the existing material does he identify spirit with a divine principle or god,” as one scholar has pointed out.

Deeper still, Anaxagoras identified a key problem that has since perplexed practitioners of science: the relationship between reason and the senses. It was absolute devotion to reason – and absolute disregard for the senses – that led Parmenides to explain reason illusively the way of truth and sense phenomena.

Anaxagoras fully agreed that the senses can be misleading, calling them “weak” and not “able to discern what is true.” Human senses are simply not sharp enough to perceive reality in full HD clarity. Reality is more than we can see.

But – most importantly – with senses supplemented with intellect, we can deduce a lot about the deeper, invisible reality from what we do see, Anaxagoras realized. “Appearances are visions of things that are invisible,” he wrote, or in another translation, “appearances are a sight of the invisible.

” Reality is richer than what it immediately appears, but the human mind remains able to explore and learn much about it. And with that realization, progress in the scientific understanding of reality became possible. Of course, Anaxagoras’ emphasis on natural explanations and his disdain for the gods got him into trouble.

Athenian officials accused him of wickedness, condemned him and, some say to death, by others only to imprisonment. His friend, the Athenian politician Pericles, intervened to arrange the banishment, and Anaxagoras spent his last years in Lampsacus, a city in what is now northwestern Turkey, where he was revered as a champion of spirit and truth.