Pythagoras' life spans most of the sixth century and early fifth century before our common era. He is a one of the greatest Greek thinkers of all time.
He probed the cosmos with mathematics and observation. Like Socrates, however, he did not leave us any written work.
Pythagoras influenced Plato and Aristotle who shaped Greek civilization. Plato and Aristotle mentioned Pythagoras in their extensive writings. But the most detailed and trustworthy biography of Pythagoras is the work of Iamblichos, a Platonic philosopher who lived about a millennium after Pythagoras.
From comments of Plato and Aristotle and the biography of Iamblichos, the portrait of Pythagoras is of a man of enormous wisdom.
Pythagoras was born in the Aegean island of Samos. After his education in Samos, Pythagoras lived in Egypt for about twenty years and Phoenicia for some ten years. He studied with priests and visited those countries' sacred monuments. He returned to Samos and visited the Greek polis of Miletos in Asia Minor. He spent some time in Miletos studying under Thales and Anaximander, two great Greek natural philosophers.
When he returned to Samos, he moved to Croton in Magna Graecia (Southern Italy) where he founded a community and a school. Pythagoras taught at his school for about forty years.
Pythagoras introduced number as a fundamental constituent of the cosmos. This started a tradition of using geometry in measuring and understanding the natural world and the cosmos. The Pythagorean theorem (the square of the hypotenuse of a right-angled triangle equals to the sum of the squares of the other two sides of the triangle) mirrored that tradition.
Pythagoras thought of the Earth and the other heavenly bodies as spheres moving around an invisible fire at the center of the universe.
He connected the mathematical ratios of the sounds he heard from his monochord musical instrument to the music of the spheres in the heavens. He blended music, mathematics and astronomy in his search for harmony in the cosmos, a perfect, beautiful, and eternal world of stars governed by natural laws and order.
Pythagoras united the heavens and the Earth. He helped his students understand the movement of the heavenly spheres; he shed light on the eclipses of the sun and the moon. He guided his listeners to reading the night sky and studying astronomy for a better understanding of the geometry, beauty and harmony of the heavens.
Iamblichos says Pythagoras triggered "among the Greeks all the exact sciences and branches of knowledge, everything that gives the soul true vision and clears the mind blinded by other practices, so that they [the Greeks] may see the real principles and causes of all there is."
Iamblichos also says Pythagoras' "likeness to the gods" enabled him to grasp "the celestial harmonies of the cosmos... he alone could hear and understand the universal harmony and music of the spheres." This celestial music, according to Iamblichos, was more complete and satisfying than any human melody. It was made up by a diversity of sounds of motion and speeds and sizes and positions of the stars. The result was a melody of exceptional quality and beauty.
In addition, according to Iamblichos, Pythagoras established a community in Croton where "friends have all things in common," worship the gods, eat vegetarian food, respect the departed, live under laws, have the same education, respect each other, and exhibit mercy towards all living things.
These Pythagoreans avoided ignorance, disease, divisions and discord in their families and poleis; they also scorned luxury and excess of everything.
Among the gods they honored, they started with Zeus, Herakles, and the sons of Zeus, the Dioskouroi. Zeus was the originator and ruler of life; Herakles was the power of nature; and the Dioskouroi were universal harmony.
In other words, Iamblichos is making a case that Pythagoras established a model community of "lovers of learning" who lived the examined life and lived it well.
Pythagoras made a difference in Greece. Plato, Aristotle and the flowering of Greek science after Alexander the Great are not comprehensible without Pythagoras. In the tenth book of the "Republic," Plato says the followers of Pythagoras established a way of life known as Pythagorean.
Pythagoras may still make a difference in our age. However, we need to be as revolutionaries as Pythagoras: rethink, transform, or abolish our obsolete and hazardous civilization fuelled by war, money, and pollution.
Start this epic struggle by reconnecting with the natural world. Follow Pythagoras and love all living things and the Earth, above all. Imitate Pythagoras and stop eating meat.
Not eating animals would improve more than our health and the health of the natural world. It would slow down the heating of the Earth. Something like fifty percent of all global heating gases come from more than sixty billion animals we slaughter every year for food. This includes all the land we convert from forests for animal grazing and feed.
Stop eating animals would lead to the worldwide reorganization of giant industrialized agriculture to small-scale farming compatible with climate change.
A new civilization like that of Pythagoras and the Greeks could unite the natural world, the cosmos, and society. The top priorities of such a new beginning would include among other things: the replacement of Earth-warming fossil fuels with Earth-loving solar power; dramatic reduction of world population; and the elimination of humanity's worst enemies: poverty, war, and nuclear bombs.
We might call such a prospect ecological civilization. Would such a civilization lead us living like friends sharing all things in common? Probably not. But ecological civilization modeled after the Pythagorean paradigm could entice humans to live in harmony with each other and the Earth.