1. The Philosophers of ancient Ionia Chapter 3: Despina and Mateusz meeting the Philosophers of “Friends of Militos” Club

2. FRIENDS OF MILITOS After a long walk in the streets of the City of the Ancients and after meeting some of the greatest dramatic poets of Classic Ancient Greece, Despina follows Homer to a Club named “Friends of Militos”. In this place great philosophers meet each other and talk about their theories about the Universe. Homer has a surprise for her! Her friend Mateusz is there, waiting for her. Now they are both alike ancient Greek teenagers and they can’t wait to see the people Homer promised them to introduce! Ancient Ionia was a very important area. People with brilliant minds, like Thales, Anaximander, Anaximenes, Heraclitus, Anaxagoras, Aristarchus and Pythagoras, were born there and gave the world their scientific thought. Their ideas, very original and innovative, became many centuries later, the base of modern science!

3. FRIENDS OF MILITOS The Club was full of people. All the scientists were there to see Eratosthenes, a great mathematician, geographer and astronomer, who was giving a lecture about the way he calculated the circumference of the Earth! The first to see was the only woman in the Club, pretty Hypatia! Good evening Homer, welcome! You arrived just in time! Eratosthenes is ready to tell us how he manage to measure the circumference of Earth! Good to see you Hypatia!

4. Despina could not believe in her own eyes! Hypatia was there! Hypatia was her hero, she was the only known female scientist of ancient times in Greece and Egypt! Despina was very proud that women had such a great ambassador in a world only men could enter! Look Mateusz, this is Hypatia! Hypatia of Alexandria, born at 370 and died at 415, was a popular Hellenized Egyptian philosopher, mathematician, astronomer and teacher who lived in Alexandria, in Hellenistic Egypt, and contributed greatly to that city's intellectual community. She was of the Platonic school and her contributions to science are reputed to include the invention of the astrolabe and the hydrometer! Hypatia was the daughter of Theon, who was also her teacher and the last fellow of the Musaeum of Alexandria. Hypatia did not teach in the Museum, but received her pupils in her own private home. Hypatia became head of the Platonist school at Alexandria in about 400. There she lectured on mathematics and philosophy! Unfortunately she was murdered by fanatic Christians on 415 who accused her for being a witch…

5. Despina could not believe in her own eyes! Hypatia was there! Hypatia was her hero, she was the only known female scientist of ancient times in Greece and Egypt! Despina was very proud that women had such a great ambassador in a world only men could enter! Do you know what the astrobale is? The astrolabe is a historical astronomical instrument used by classical astronomers and astrologers. It was the chief navigational instrument until the invention of the sextant in the 18th century. Its many uses included locating and predicting the positions of the Sun, Moon, planets and stars; determining local time given local longitude and vice-versa; surveying; and triangulation. Astrologers of the European nations used astrolabes to construct horoscopes. In the Islamic world, they are and were used primarily for astronomical studies, though astrology was often involved there as well. Most historians credit the invention of the astrolabe to Hipparchus and some to Hypatia of Alexandria.

6. Despina could not believe in her own eyes! Hypatia was there! Hypatia was her hero, she was the only known female scientist of ancient times in Greece and Egypt! Despina was very proud that women had such a great ambassador in a world only men could enter! Hipparchus? I learned about him in Astronomy Class! He was born in Nicaea of Asia Minor on 190 BC and probably died on the island of Rhodes on 120 BC. He was a astronomer, geographer and mathematician! He was a working astronomer at least from 147 BC to 127 BC and he is considered the greatest astronomical observer and, by some, the greatest overall astronomer of antiquity. He was the first Greek to develop quantitative and accurate models for the motion of the Sun and Moon. He was also the first to compile a trigonometric table, which allowed him to solve any triangle. With his solar and lunar theories and his numerical trigonometry, he was probably the first to develop a reliable method to predict solar eclipses! Another of his achievements is the compilation of the first star catalogue of the western world!

7. But now Despina and Mateusz have to stop their conversation! Eratosthenes is ready to start his lecture! Dear friends, I welcome you! I hope you’ll find my method interesting. I knew that on the summer solstice at local noon in the town of Syene on the Tropic of Cancer, the sun would appear at the zenith, directly overhead. I also knew, from measurement, that in my hometown of Alexandria, the angle of elevation of the Sun would be 7.2° south of the zenith at the same time. Assuming that Alexandria was due north of Syene, I concluded that the distance from Alexandria to Syene must be 7.2/360 of the total circumference of the Earth. The distance between the cities is known from caravan travellings to be about 5000 stadia: approximately 800 km. I established a final value of 700 stadia per degree, which implies a circumference of 252,000 stadia. A stadion is about 185 m. So, the circumference calculated corresponds to 39,690 km!

8. He is very good this Eratosthenes! The accuracy of his result is surprising: the circumference of the Earth around the poles is now measured at 40,008 km. Tell us about Eratosthenes Homer! Who was he? Eratosthenes was born in Cyrene (Libya) in 276 BC and worked in Alexandria capital of Ptolemaic Egypt and he died there in 194 BC. He was a mathematician, geographer and astronomer. He is noted for devising a system of latitude and longitude, and for being the first known to have calculated the circumference of the Earth. Eratosthenes studied at Alexandria and for some years in Athens. In 236 BC he was appointed by Ptolemy III as librarian of the Alexandrian library, succeeding the first librarian, Zenodotos, in that post. He made several important contributions to mathematics and science, and was a good friend to Archimedes. Around 255 BC he invented the armillary sphere. In 195 BC he became blind and a year later he supposedly starved himself to death.

9. Very good in did! Do you know the other people in this Club? Despina knows Hypatia but who are the others? Are they scientists like Eratosthenes? Of course he knows, tell us Homer! Who are they? Oh yes, I know them very well! They are the company of Anax!!!! Anaxagoras the philosopher, Anaximander the physical philosopher and Anaximenes, pupil of Anaximander! AnaxagorasAnaximander Anaximenes

10. Anaxagoras (500 BC–428 BC) was a pre- Socratic Greek philosopher. He was a member of the Ionian School of philosophy. His native town is Clazomenae in Asia Minor. In early manhood (c. 464-462 BC) he went to Athens. 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. Some authorities assert that even Socrates was among his disciples. He brought philosophy and the spirit of scientific inquiry from Ionia to Athens. His observations of the celestial bodies 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. The heavenly bodies, he asserted, were masses of stone torn from the earth and ignited by rapid rotation. However, these theories brought him into collision with the popular faith. He was arrested on a charge of contravening the established dogmas of religion and so he was forced to retire from Athens to Lampsacus in Ionia (c. 434-433 BC) He died there in around the year 428 BC. Back…

11. Anaximander (610 BC – 546 BC) was a physical philosopher from Ionia. He was citizen of Miletus, pupil of Thales and teacher of Anaximenes. He was a successful student of astronomy and geography, and an early proponent of exact science. He has also been said to have introduced such astronomical instruments as the sundial and the gnomon to ancient Greece. He is also credited with having created the first map of the world, which was circular in form and showed the known lands of the world grouped around the Aegean Sea at the center and all of this was surrounded by the ocean. His reputation is due mainly to his cosmological work: he took the beginning or first principle to be an endless, unlimited primordial mass (apeiron), subject to neither old age nor decay, which perpetually yields fresh materials from which everything is derived. Out of the vague and limitless body there sprang a central mass — the earth, cylindrical in shape, poised equidistant from surrounding orbs of fire, which had originally clung to it like the bark round a tree, until their continuity was severed, and they parted into several wheel-shaped and fire-filled bubbles of air. Back…

12. Anaximenes of Miletus (585 BC – 525 BC) was a Greek philosopher probably a younger contemporary of Anaximander, whose pupil or friend he is said to have been. He held that the air, with its variety of contents, its universal presence, its vague associations in popular fancy with the phenomena of life and growth, is the source of all that exists. Everything is air at different degrees of density, and under the influence of heat, which expands, and of cold, which contracts its volume, it gives rise to the several phases of existence. The process is gradual, and takes place in two directions, as heat or cold predominates. In this way was formed a broad disk of earth, floating on the circumambient air. Similar condensations produced the sun and stars; and the flaming state of these bodies is due to the velocity of their motions. He states: "Just as our soul, being air, holds us together, so do breath and air encompass the whole world." Back…

13. That’s so funny! The three Anax! Are all the names of the scientists start with “anax”? All of them? Oh no! Some of the names start with an “ar”, like Archimedes, Aristotle and Aristarchus, my dear friend from the island of Samos! Do you know that he was the first astronomer to propose a heliocentric model of the solar system?