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Thales of Miletus (624-620 BC/548-545 BC) was an Ancient Greek philosopher and one of the Seven Sages of Greece. He is known for his belief that everything has a basic principle and his contributions to mathematics and astronomy, claiming that the Earth is a flat disk floating in a vast sea.

APA 7: Çarıkçıoğlu, A. E. (2023, April 25). Thales. PerEXP Teamworks. [Article Link]

His life and contributions

Thales of Miletus (624-620 BC/548-545 BC) is a philosopher known as one of the legendary ”Seven Sages“ (Also referred to as the ”Sage of the Golden Age”.). He is known for his understanding of the universe, which he developed after adopting water as the essence of everything (Arkhe), and for claiming that the Earth is a flat disk floating in a vast sea. [1]

The Greek historian Diogenes Laërtius (”Diogenes Laertios”, lived in the third century AD.), Apollodorus of Athens (One of the most important historians of the second century BC.) He stated that the date of Thales’ birth coincided with the Thirty-Fifth Ancient Olympic Games (Olympiad) with the inferences he made from the sources he transmitted information about Thales (This is a typo, Thales was born in the Thirty-Ninth Olympiad.). He also estimated that he died at the Fifty-Eighth Olympiad (548-545 BC), that is, at the age of 78. [2]

His science and more

The scientific value of Thales lies in his attempt to explain the simplification of the phenomena of nature and his search for various causes in nature itself, rather than the behavior of anthropomorphic (Human-shaped) gods. Historians also state that he used his knowledge of geometry to measure the Egyptian pyramids and calculate the distance of ships at sea to the shore. Such stories (Although there is a possibility of an exaggeration) reinforce the reputation of Thales. [3]

The poet and philosopher Xenophanes (560-478 BC) made it clear that Thales predicted the Solar eclipse on May 28, 585 BC, which stopped the war between the Lydian King Aly Dectes (610-560 BC) and the Media King Cyaxares (“Cyaxares”, 625-585 BC). However, today’s scientists do not know the location or character of an eclipse (The “Masculine” and “Feminine” types of eclipses in astrology are completely irrational. The concept of “Character” mentioned here is related to the degree of the eclipse: full, half, etc…) they believe that he may not have the knowledge to predict correctly. Thus, his achievements have clearly become legends, and he was only close to what was written.

Herodotus mentioned that Thales only foresaw the year of the eclipse. The fact that there was an almost total eclipse and that it occurred during a very important battle, contributed significantly to his extravagant reputation as an astronomer. [4]

The discovery of the theorem consisting of six geometric proofs is attributed to Thales:

  1. According to ”Thales’ Theorem”, there is a proportion between the sides of similar triangles whose angles are the same. Based on this, Thales calculated the height of the pyramids by comparing the length of the shadow with the help of a stick, the length of which he knew.
  2. The circumference angle, which sees the radius in a circle, is perpendicular.
  3. The diameter of the circle divides it into two equal parts
  4. The base angles of an isosceles triangle are equal.
  5. Opposite angles are equal.
  6. Triangles with one edge and two angles equal are equal.

Also, Thales believed that “Everything is full of gods” according to Aristotle, and that metals such as iron have souls because magnetic objects can move them. His heirs are Anaximander (610-546/545 BC) and Anaximenes of Miletus (Died around 545 BC at the age of 64.), he believed that it is the soul that distinguishes living from inanimate things, and that change by movement (Or the ability to move, change other things) is the essence of life. As a result, Thales; by stripping the mind of myths, helped logic come to the fore and laid the foundations of “Scientific thought”. [5]


  1. DICTIONARY ENTRY Britannica, T. Editors of Encyclopaedia (2023, January 25). Thales of MiletusEncyclopedia Britannica. [Britannica]
  2. DICTIONARY ENTRY Britannica, T. Editors of Encyclopaedia (2020, May 2). Thales of Miletus summaryEncyclopedia Britannica. [Britannica]
  3. WEBSITE Leblebitozu. (2018, August 3). Thales Kimdir? Thales’in Hayatı ve Teoremi. Leblebitozu. [Leblebitozu]
  4. BOOK Arslan, A. (2006). İlkçağ Felsefe Tarihi: Sokrates Öncesi ve Yunan Felsefesi. İstanbul Bilgi Üniversitesi Yayınları
  5. BOOK Laertios, D. (2003). Ünlü Filozofların Yas̈amları ve Öğretileri: Diogenes Laertios. Yapı Kredi Yayınları.

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