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Thales of Miletus ( ; grc-gre, Θαλῆς; ) was a
Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...
mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...
,
astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...
, statesman, and
pre-Socratic philosopher Pre-Socratic philosophy, also known as early Greek philosophy, is ancient Greek philosophy before Socrates. Pre-Socratic philosophers were mostly interested in cosmology, the beginning and the substance of the universe, but the inquiries of thes ...
from
Miletus Miletus (; gr, Μῑ́λητος, Mī́lētos; Hittite language, Hittite transcription ''Millawanda'' or ''Milawata'' (Exonym and endonym, exonyms); la, Mīlētus; tr, Milet) was an Ancient Greece, ancient Greek city on the western coast of ...
in
Ionia Ionia () was an ancient region on the western coast of Anatolia, to the south of present-day Izmir. It consisted of the northernmost territories of the Ionian League of Greeks, Greek settlements. Never a unified state, it was named after the I ...
,
Asia Minor Anatolia (also Asia Minor), is a large peninsula in Western Asia and is the western-most extension of continental Asia. The land mass of Anatolia constitutes most of the territory of contemporary Turkey. Geographically, the Anatolian region i ...
. He was one of the Seven Sages of Greece. Many, most notably
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical Greece, Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatet ...
, regarded him as the first philosopher in the Greek tradition, and he is otherwise historically recognized as the first individual known to have entertained and engaged in scientific philosophy.Frank N. Magill
''The Ancient World: Dictionary of World Biography'', Volume 1
Routledge, 2003
He is often referred to as the Father of Science. Thales is recognized for breaking from the use of
mythology Myth is a folklore genre consisting of narratives that play a fundamental role in a society, such as foundational tales or origin myths. Since "myth" is widely used to imply that a story is not objectively true, the identification of a narra ...
to explain the world and the universe, instead explaining natural objects and phenomena by offering naturalistic theories and hypotheses. Almost all the other pre-Socratic philosophers followed him in explaining nature as deriving from a unity of everything based on the existence of a single ultimate substance instead of using mythological explanations.
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical Greece, Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatet ...
regarded him as the founder of the Ionian School of philosophy, and reported Thales' hypothesis that the originating principle of
nature Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...
and the nature of
matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic partic ...
was a single material
substance Substance may refer to: * Matter, anything that has mass and takes up space Chemistry * Chemical substance, a material with a definite chemical composition * Drug substance ** Substance abuse, drug-related healthcare and social policy diagnosis o ...
:
water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
. In
mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...
, Thales used
geometry Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is ca ...
to calculate the heights of pyramids and the distance of ships from the shore. He is the first known individual to use
deductive reasoning Deductive reasoning is the mental process of drawing deductive inferences. An inference is deductively Validity (logic), valid if its conclusion follows logically from its premises, i.e. if it is impossible for the premises to be true and the concl ...
applied to geometry by deriving four corollaries to Thales' theorem. He is also the first known to whom a mathematical discovery has been attributed.


Life

The dates of Thales' life are not exactly known, but are roughly established by a few datable events mentioned in the sources. According to
Herodotus Herodotus ( ; grc, , }; BC) was an ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided in ...
, Thales predicted the solar eclipse of 28 May 585 BC.Herodotus
1.74.2
and A. D. Godley's footnote 1; Pliny
2.9 (12)
and Bostock's footnote 2.
Diogenes Laërtius Diogenes Laërtius ( ; grc-gre, Διογένης Λαέρτιος, ; ) was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving ''Lives and Opinions of Eminent Philosophers'' is a principal sou ...
quotes the chronicle of Apollodorus of Athens as saying that Thales died at the age of 78 during the 58th
Olympiad An olympiad ( el, Ὀλυμπιάς, ''Olympiás'') is a period of four years, particularly those associated with the ancient and modern Olympic Games. Although the ancient Olympics were established during Greece's Archaic Era, it was not unt ...
(548–545 BC) and attributes his death to
heat stroke Heat stroke or heatstroke, also known as sun stroke, is a severe heat illness that results in a body temperature greater than , along with red skin, headache, dizziness, and confusion. Sweating is generally present in exertional heatstroke, b ...
while watching the games. Thales was probably born in the city of Miletus around the mid-620s BC. The ancient writer Apollodorus of Athens writing during the 2nd century BC, thought Thales was born about the year 625 BC.


Ancestry and family

Herodotus Herodotus ( ; grc, , }; BC) was an ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided in ...
, writing in the 5th century BC, described Thales as "a
Phoenicia Phoenicia () was an ancient Semitic-speaking peoples, ancient thalassocracy, thalassocratic civilization originating in the Levant region of the eastern Mediterranean, primarily located in modern Lebanon. The territory of the Phoenician city-st ...
n by remote descent". The later historian
Diogenes Laërtius Diogenes Laërtius ( ; grc-gre, Διογένης Λαέρτιος, ; ) was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving ''Lives and Opinions of Eminent Philosophers'' is a principal sou ...
, in his third century AD '' Lives of the Philosophers'', references Herodotus, Duris, and
Democritus Democritus (; el, Δημόκριτος, ''Dēmókritos'', meaning "chosen of the people"; – ) was an Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient ...
, who all agree "that Thales was the son of Examyas and Cleobulina, and belonged to the Thelidae who are Phoenicians and amongst the noblest descendants of
Cadmus In Greek mythology, Cadmus (; grc-gre, Κάδμος, Kádmos) was the legendary Phoenician founder of Boeotian Thebes, Greece, Thebes. He was the first Greek hero and, alongside Perseus and Bellerophon, the greatest hero and slayer of monsters ...
and
Agenor Agenor (; Ancient Greek: Ἀγήνωρ or Αγήνορας ''Agēnor''; English language, English translation: "heroic, manly") was in Greek mythology and history a Phoenician monarch, king of Tyre, Lebanon, Tyre or Sidon. The Dorians, Doric Gr ...
" who had been banished from Phoenicia and that Thales was enrolled as a citizen in Miletus along with
Neleus Neleus (; Ancient Greek: Νηλεύς) was a mythological king of Pylos. In some accounts, he was also counted as an Argonaut instead of his son, Nestor (mythology), Nestor. Family Neleus was the son of Poseidon and Tyro. According to Pausanias ...
.
Friedrich Nietzsche Friedrich Wilhelm Nietzsche (; or ; 15 October 1844 – 25 August 1900) was a German philosopher, Prose poetry, prose poet, cultural critic, Philology, philologist, and composer whose work has exerted a profound influence on contemporary philo ...
interprets this as meaning "only that his forefathers belonged to the seafaring people of
Cadmus In Greek mythology, Cadmus (; grc-gre, Κάδμος, Kádmos) was the legendary Phoenician founder of Boeotian Thebes, Greece, Thebes. He was the first Greek hero and, alongside Perseus and Bellerophon, the greatest hero and slayer of monsters ...
". However, Diogenes Laërtius then reports of a conflicting account, stating that: "Most writers, however, represent him as a genuine Milesian and of a distinguished family". In addition, his supposed mother, Cleobulina, has also been described as his companion instead of his mother. The probability is that Thales was as Greek as most Milesians. It is possible that he was of mixed ancestry as his ancestors were likely Cadmeians from
Boeotia Boeotia ( ), sometimes Latinisation of names, Latinized as Boiotia or Beotia ( el, wikt:Βοιωτία, Βοιωτία; modern Greek, modern: ; ancient Greek, ancient: ), formerly known as Cadmeis, is one of the regional units of Greece. It is pa ...
coupled with the fact of his father having a Carian name. ''
Encyclopedia Britannica An encyclopedia (American English) or encyclopædia (British English) is a reference work or compendium providing summaries of knowledge either general or special to a particular field or discipline. Encyclopedias are divided into article ( ...
'' (1952) concluded that Thales was most likely a native Milesian of noble birth and that he was certainly a
Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...
. Diogenes continues, by delivering more conflicting reports: one that Thales married and either fathered a son ( Cybisthus or Cybisthon) or adopted his nephew of the same name; the second that he never married, telling his mother as a young man that it was too early to marry, and as an older man that it was too late.
Plutarch Plutarch (; grc-gre, Πλούταρχος, ''Ploútarchos''; ; – after AD 119) was a Greek people, Greek Middle Platonism, Middle Platonist philosopher, historian, Biography, biographer, essayist, and priest at the Temple of Apollo (D ...
had earlier told this version:
Solon Solon ( grc-gre, wikt:Σόλων, Σόλων;  BC) was an History of Athens, Athenian statesman, constitutional lawmaker and poet. He is remembered particularly for his efforts to legislate against political, economic and moral decline in A ...
visited Thales and asked him why he remained single; Thales answered that he did not like the idea of having to worry about children. Nevertheless, several years later, anxious for family, he adopted his nephew Cybisthus.


Travels

Some assume that Thales, at one point in his life, visited
Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a List of transcontinental countries, transcontinental country spanning the North Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via a land bridg ...
, where he learned about geometry. It is not impossible that Thales visited Egypt, since Miletus had a permanent colony there (namely Naucratis), however visits to Egypt were a commonplace attribution to various philosophers by later writers, especially when these writers tried to explain mathematical knowledge. However, Thales may have known about Egypt from accounts of others, without actually visiting it. There is no strong evidence that Thales ever visited countries in the
Near East The ''Near East''; he, המזרח הקרוב; arc, ܕܢܚܐ ܩܪܒ; fa, خاور نزدیک, Xāvar-e nazdik; tr, Yakın Doğu is a geographical term which roughly encompasses a transcontinental region in Western Asia, that was once the hist ...
.


Activities

Thales (who was born about 50 years before
Pythagoras Pythagoras of Samos ( grc, Πυθαγόρας ὁ Σάμιος, Pythagóras ho Sámios, Pythagoras the Samos, Samian, or simply ; in Ionian Greek; ) was an ancient Ionians, Ionian Ancient Greek philosophy, Greek philosopher and the eponymou ...
and 300 years before
Euclid Euclid (; grc-gre, Wikt:Εὐκλείδης, Εὐκλείδης; BC) was an ancient Greek mathematician active as a geometer and logician. Considered the "father of geometry", he is chiefly known for the ''Euclid's Elements, Elements'' trea ...
) is often hailed as "the first Greek mathematician". While some historians, such as Colin R. Fletcher, point out that there could have been a predecessor to Thales who would have been named in Eudemus' lost book ''History of Geometry'', it is admitted that without the work "the question becomes mere speculation." Fletcher holds that as there is no viable predecessor to the title of first Greek mathematician, the only question is whether Thales qualifies as a practitioner in that field; he holds that "Thales had at his command the techniques of observation, experimentation, superposition and deduction...he has proved himself mathematician." Aristotle wrote in Metaphysics, "Thales, the founder of this school of philosophy, says the permanent entity is water (which is why he also propounded that the earth floats on water). Presumably he derived this assumption from seeing that the nutriment of everything is moist, and that heat itself is generated from moisture and depends upon it for its existence (and that from which a thing is generated is always its first principle). He derived his assumption from this; and also from the fact that the seeds of everything have a moist nature, whereas water is the first principle of the nature of moist things." Thales involved himself in many activities, including
engineering Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more specializ ...
. Some say that he left no writings. Others say that he wrote ''On the
Solstice A solstice is an event that occurs when the Sun appears to reach its most northerly or southerly sun path, excursion relative to the celestial equator on the celestial sphere. Two solstices occur annually, around June 21 and December 21. In man ...
'' and ''On the
Equinox A solar equinox is a moment in time when the Sun crosses the Earth's equator, which is to say, appears zenith, directly above the equator, rather than north or south of the equator. On the day of the equinox, the Sun appears to rise "due east" ...
''. The ''Nautical Star-guide'' has been attributed to him, but this was disputed in ancient times. No writing attributed to him has survived. Diogenes Laërtius quotes two letters from Thales: one to
Pherecydes of Syros Pherecydes of Syros (; grc-gre, Φερεκύδης ὁ Σύριος; fl. 6th century BCE) was an Ancient Greeks, Ancient Greek mythographer and proto-philosopher from the island of Syros. Little is known about his life and death. Some ancient ...
, offering to review his book on religion, and one to
Solon Solon ( grc-gre, wikt:Σόλων, Σόλων;  BC) was an History of Athens, Athenian statesman, constitutional lawmaker and poet. He is remembered particularly for his efforts to legislate against political, economic and moral decline in A ...
, offering to keep him company on his sojourn from
Athens Athens ( ; el, Αθήνα, Athína ; grc, Ἀθῆναι, Athênai (pl.) ) is a coastal city in the Mediterranean and is both the capital and largest city of Greece. With a population close to four million, it is also the seventh largest c ...
.


Olive story as example of option type trade

A story, with different versions, recounts how Thales achieved riches from an olive harvest by prediction of the weather. In one version, he bought all the olive presses in Miletus after predicting the weather and a good harvest for a particular year. Another version of the story has Aristotle explain that Thales had reserved presses in advance, at a discount, and could rent them out at a high price when demand peaked, following his prediction of a particularly good harvest. This first version of the story would constitute the first historically known creation and use of futures, whereas the second version would be the first historically known creation and use of options. Aristotle explains that Thales' objective in doing this was not to enrich himself but to prove to his fellow Milesians that philosophy could be useful, contrary to what they thought, or alternatively, Thales had made his foray into enterprise because of a personal challenge put to him by an individual who had asked why, if Thales was an intelligent famous philosopher, he had yet to attain wealth.


Advisor role

Diogenes Laërtius Diogenes Laërtius ( ; grc-gre, Διογένης Λαέρτιος, ; ) was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving ''Lives and Opinions of Eminent Philosophers'' is a principal sou ...
tells us that Thales gained fame as a counselor when he advised the Milesians not to engage in a symmachia, a "fighting together", with the Lydians. This has sometimes been interpreted as an alliance. Another story by Herodotus is that
Croesus Croesus ( ; Lydian language, Lydian: ; Phrygian language, Phrygian: ; grc, :wikt:Κροῖσος, Κροισος, Kroisos; Latin: ; reigned: c. 585 – c. 546 BC) was the Monarch, king of Lydia, who reigned from 585 BC until his Siege of Sar ...
sent his army to the Persian territory. He was stopped by the river Halys, then unbridged. Thales then got the army across the river by digging a diversion upstream so as to reduce the flow, making it possible to cross the river. While Herodotus reported that most of his fellow Greeks believe that Thales did divert the river Halys to assist King Croesus' military endeavors, he himself finds it doubtful. Croesus was defeated before the city of
Sardis Sardis () or Sardes (; Lydian language, Lydian: 𐤳𐤱𐤠𐤭𐤣 ''Sfard''; el, Σάρδεις ''Sardeis''; peo, Sparda; hbo, ספרד ''Sfarad'') was an ancient city at the location of modern ''Sart'' (Sartmahmut before 19 October 2005) ...
by Cyrus, who subsequently spared Miletus because it had taken no action. Cyrus was so impressed by Croesus’ wisdom and his connection with the sages that he spared him and took his advice on various matters. The Ionian cities should be demoi, or "districts". Miletus, however, received favorable terms from Cyrus. The others remained in an Ionian League of twelve cities (excluding Miletus), and were subjugated by the Persians.


Astronomy

According to Herodotus, Thales predicted the solar eclipse of 28 May 585 BC. Thales also described the position of Ursa Minor, and he thought the constellation might be useful as a guide for navigation at sea. He calculated the duration of the year and the timings of the
equinoxes A solar equinox is a moment in time when the Sun crosses the Earth's equator, which is to say, appears zenith, directly above the equator, rather than north or south of the equator. On the day of the equinox, the Sun appears to rise "due east" ...
and solstices. He is additionally attributed with the first observation of the Hyades and with calculating the position of the
Pleiades The Pleiades (), also known as The Seven Sisters, Messier 45 and other names by different cultures, is an Asterism (astronomy), asterism and an open cluster, open star cluster containing middle-aged, hot Stellar classification#Class B, B-type st ...
.
Plutarch Plutarch (; grc-gre, Πλούταρχος, ''Ploútarchos''; ; – after AD 119) was a Greek people, Greek Middle Platonism, Middle Platonist philosopher, historian, Biography, biographer, essayist, and priest at the Temple of Apollo (D ...
indicates that in his day (c. AD 100) there was an extant work, the ''Astronomy'', composed in verse and attributed to Thales.
Herodotus Herodotus ( ; grc, , }; BC) was an ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided in ...
writes that in the sixth year of the war, the Lydians under King Alyattes and the Medes under
Cyaxares Cyaxares (Median language, Median: ; Old Persian: ; Akkadian language, Akkadian: ; Phrygian language, Old Phrygian: ; grc, wikt:Κυαξάρης, Κυαξαρης, Kuaxarēs; Latin: ; reigned 625–585 BCE) was the third king of the Medes. C ...
were engaged in an indecisive battle when suddenly day turned into night, leading to both parties halting the fighting and negotiating a peace agreement. Herodotus also mentions that the loss of daylight had been predicted by Thales. He does not, however, mention the location of the battle. However, based on the list of Median kings and the duration of their reign reported elsewhere by Herodotus, Cyaxares died 10 years before the eclipse.


Sagacity

Diogenes Laërtius Diogenes Laërtius ( ; grc-gre, Διογένης Λαέρτιος, ; ) was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving ''Lives and Opinions of Eminent Philosophers'' is a principal sou ...
tells us that the Seven Sages were created in the
archon ''Archon'' ( gr, ἄρχων, árchōn, plural: ἄρχοντες, ''árchontes'') is a Greek word that means "ruler", frequently used as the title of a specific public office. It is the masculine present participle of the verb stem αρχ-, mean ...
ship of Damasius at
Athens Athens ( ; el, Αθήνα, Athína ; grc, Ἀθῆναι, Athênai (pl.) ) is a coastal city in the Mediterranean and is both the capital and largest city of Greece. With a population close to four million, it is also the seventh largest c ...
about 582 BC and that Thales was the first sage. The same story, however, asserts that Thales emigrated to
Miletus Miletus (; gr, Μῑ́λητος, Mī́lētos; Hittite language, Hittite transcription ''Millawanda'' or ''Milawata'' (Exonym and endonym, exonyms); la, Mīlētus; tr, Milet) was an Ancient Greece, ancient Greek city on the western coast of ...
. There is also a report that he did not become a student of
nature Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...
until after his political career. Much as we would like to have a date on the seven sages, we must reject these stories and the tempting date if we are to believe that Thales was a native of Miletus, predicted the eclipse, and was with
Croesus Croesus ( ; Lydian language, Lydian: ; Phrygian language, Phrygian: ; grc, :wikt:Κροῖσος, Κροισος, Kroisos; Latin: ; reigned: c. 585 – c. 546 BC) was the Monarch, king of Lydia, who reigned from 585 BC until his Siege of Sar ...
in the campaign against Cyrus. Thales was said to have had close contacts with priests of Thebes and instructed them in geometry. In Diogenes Laërtius' ''Lives of Eminent Philosophers'' Chapter 1.39, Laërtius relates several stories of an expensive object that is to go to the most wise. In one version (that Laërtius credits to
Callimachus Callimachus (; ) was an ancient Greek poet, scholar and librarian who was active in Alexandria during the 3rd century BC. A representative of Ancient Greek literature of the Hellenistic period, he wrote over 800 literary works in a wide variety ...
in his ''Iambics'') Bathycles of Arcadia states in his will that an expensive bowl "'should be given to him who had done most good by his wisdom.' So it was given to Thales, went the round of all the sages, and came back to Thales again. And he sent it to Apollo at Didyma, with this dedication...'Thales the Milesian, son of Examyas edicates thisto Delphinian Apollo after twice winning the prize from all the Greeks.'"


Theories

Early Greeks, and other civilizations before them, often invoked
idiosyncratic An idiosyncrasy is an unusual feature of a person (though there are also other uses, see below). It can also mean an odd habit. The term is often used to express Eccentricity (behavior), eccentricity or peculiarity. A synonym may be "wikt:quirk, qu ...
explanations of natural phenomena with reference to the will of
anthropomorphic Anthropomorphism is the attribution of human traits, emotions, or intentions to non-human entities. It is considered to be an innate tendency of human psychology. Personification is the related attribution of human form and characteristics t ...
gods A deity or god is a supernatural being who is considered divinity, divine or sacred. The ''Oxford Dictionary of English'' defines deity as a God (male deity), god or goddess, or anything revered as divine. C. Scott Littleton defines a deity as " ...
and
hero A hero (feminine: heroine) is a real person or a main fictional character who, in the face of danger, combats adversity through feats of ingenuity, courage, or Physical strength, strength. Like other formerly gender-specific terms (like ...
es. Instead, Thales aimed to explain natural phenomena via rational hypotheses that referenced natural processes themselves. For example, rather than assuming that earthquakes were the result of supernatural whims, Thales explained them by hypothesizing that the
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large list of largest lakes and seas in the Solar System, volumes of water can be found throughout the Solar System, only water distributi ...
floats on water and that earthquakes occur when the Earth is rocked by waves. Thales was a hylozoist (one who thinks that matter is alive, i.e. containing soul(s)). Aristotle wrote (''
De Anima ''On the Soul'' (Ancient Greek, Greek: , ''Peri Psychēs''; Latin: ''De Anima'') is a major treatise written by Aristotle c. 350 BC. His discussion centres on the kinds of souls possessed by different kinds of living things, distinguished by the ...
'' 411 a7-8) of Thales: ...''Thales thought all things are full of gods''. Aristotle posits the origin of Thales thought on matter generally containing souls, to Thales thinking initially on the fact of, because
magnets A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, ...
move iron, the presence of movement of matter indicated this matter contained life. Thales, according to
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical Greece, Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatet ...
, asked what was the nature (Greek ''
arche ''Arche'' (; grc, :wikt:ἀρχή, ἀρχή; sometimes also transcribed as ''arkhé'') is a Greek word with primary senses "beginning", "origin" or "source of action" (: from the beginning, οr : the original argument), and later "first principl ...
'') of the object so that it would behave in its characteristic way.
Physis Fusis, Phusis or Physis (; grc, φύσις ) is a Greek philosophical Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, Epistemology, knowledge, Ethics, values, ...
() comes from phyein (), "to grow", related to our word "be". ''(G)natura'' is the way a thing is "born", again with the stamp of what it is in itself. Aristotle characterizes most of the philosophers "at first" () as thinking that the "principles in the form of matter were the only principles of all things", where "principle" is
arche ''Arche'' (; grc, :wikt:ἀρχή, ἀρχή; sometimes also transcribed as ''arkhé'') is a Greek word with primary senses "beginning", "origin" or "source of action" (: from the beginning, οr : the original argument), and later "first principl ...
, "matter" is hyle ("wood" or "matter", "material") and "form" is eidos. ''Arche'' is translated as "principle", but the two words do not have precisely the same meaning. A
principle A principle is a proposition or value that is a guide for behavior or evaluation. In law, it is a Legal rule, rule that has to be or usually is to be followed. It can be desirably followed, or it can be an inevitable consequence of something, suc ...
of something is merely prior (related to pro-) to it either chronologically or logically. An arche (from , "to rule") dominates an object in some way. If the arche is taken to be an origin, then specific causality is implied; that is, B is supposed to be characteristically B just because it comes from A, which dominates it. The archai that Aristotle had in mind in his well-known passage on the first Greek scientists are not necessarily chronologically prior to their objects, but are constituents of it. For example, in pluralism objects are composed of earth, air, fire and water, but those elements do not disappear with the production of the object. They remain as archai within it, as do the atoms of the atomists. What Aristotle is really saying is that the first philosophers were trying to define the substance(s) of which all material objects are composed. As a matter of fact, that is exactly what modern scientists are attempting to accomplish in
nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies the ...
, which is a second reason why Thales is described as the first western scientist, but some contemporary scholars reject this interpretation.


Geometry

Thales was known for his theoretical and practical use of
geometry Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is ca ...
, and is often considered the first person in the western world to have applied deductive reasoning to geometry (and by extension is often considered the first western mathematician). His understanding was theoretical as well as practical. For example, he said: Thales understood similar triangles and
right triangle A right triangle (American English) or right-angled triangle (British English, British), or more formally an orthogonal triangle, formerly called a rectangled triangle ( grc, ὀρθόσγωνία, lit=upright angle), is a triangle in which one an ...
s, and what is more, used that knowledge in practical ways. The story is told in
Diogenes Laërtius Diogenes Laërtius ( ; grc-gre, Διογένης Λαέρτιος, ; ) was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving ''Lives and Opinions of Eminent Philosophers'' is a principal sou ...
(loc. cit.) that he measured the height of the
pyramids A pyramid (from el, πυραμίς ') is a Nonbuilding structure, structure whose outer surfaces are triangular and converge to a single step at the top, making the shape roughly a Pyramid (geometry), pyramid in the geometric sense. The base o ...
by their shadows at the moment when his own shadow was equal to his height. A right triangle with two equal legs is a 45-degree right triangle, all of which are similar. The length of the pyramid's shadow measured from the center of the pyramid at that moment must have been equal to its height. This story indicates that he was familiar with the Egyptian '' seked'', or ''seqed'', the ratio of the run to the rise of a
slope In mathematics, the slope or gradient of a line Line most often refers to: * Line (geometry) In geometry, a line is an infinitely long object with no width, depth, or curvature. Thus, lines are One-dimensional space, one-dimensional object ...
(
cotangent In mathematics, the trigonometric functions (also called circular functions, angle functions or goniometric functions) are real functions which relate an angle of a right-angled triangle to ratios of two side lengths. They are widely used in all ...
). The ''seked'' is at the base of problems 56, 57, 58, 59 and 60 of the Rhind papyrus — an ancient Egyptian mathematical document. More practically Thales used the same method to measure the distances of ships at sea, said Eudemus as reported by
Proclus Proclus Lycius (; 8 February 412 – 17 April 485), called Proclus the Successor ( grc-gre, Πρόκλος ὁ Διάδοχος, ''Próklos ho Diádokhos''), was a Greek philosophy, Greek Neoplatonism, Neoplatonist Philosophy, philosopher, ...
("in Euclidem"). According to Kirk & Raven, all you need for this feat is three straight sticks pinned at one end and knowledge of your altitude. One stick goes vertically into the ground. A second is made level. With the third you sight the ship and calculate the ''seked'' from the height of the stick and its distance from the point of insertion to the line of sight (Proclus, ''In Euclidem'', 352).


Thales' theorems

There are two theorems of Thales in
elementary geometry Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is ca ...
, one known as Thales' theorem having to do with a triangle inscribed in a circle and having the circle's diameter as one leg, the other theorem being also called the intercept theorem. In addition Eudemus attributed to him the discovery that a circle is bisected by its diameter, that the base angles of an isosceles triangle are equal and that vertical angles are equal. According to a historical Note, when Thales visited
Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a List of transcontinental countries, transcontinental country spanning the North Africa, northeast corner of Africa and Western Asia, southwest corner of Asia via a land bridg ...
, he observed that whenever the Egyptians drew two intersecting lines, they would measure the vertical angles to make sure that they were equal. Thales concluded that one could prove that all vertical angles are equal if one accepted some general notions such as: all straight angles are equal, equals added to equals are equal, and equals subtracted from equals are equal. The evidence for the primacy of Thales comes to us from a book by
Proclus Proclus Lycius (; 8 February 412 – 17 April 485), called Proclus the Successor ( grc-gre, Πρόκλος ὁ Διάδοχος, ''Próklos ho Diádokhos''), was a Greek philosophy, Greek Neoplatonism, Neoplatonist Philosophy, philosopher, ...
who wrote a thousand years after Thales but is believed to have had a copy of Eudemus' book. Proclus wrote "Thales was the first to go to Egypt and bring back to Greece this study." He goes on to tell us that in addition to applying the knowledge he gained in Egypt "He himself discovered many propositions and disclosed the underlying principles of many others to his successors, in some case his method being more general, in others more empirical." Other quotes from Proclus list more of Thales' mathematical achievements: In addition to Proclus, Hieronymus of Rhodes also cites Thales as the first Greek mathematician. Hieronymus held that Thales was able to measure the height of the pyramids by using a
theorem In mathematics, a theorem is a statement (logic), statement that has been Mathematical proof, proved, or can be proved. The ''proof'' of a theorem is a logical argument that uses the inference rules of a deductive system to establish that the th ...
of geometry now known as the intercept theorem, (after gathering data by using his walking-stick and comparing its shadow to those cast by the pyramids). We receive variations of Hieronymus' story through
Diogenes Laërtius Diogenes Laërtius ( ; grc-gre, Διογένης Λαέρτιος, ; ) was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving ''Lives and Opinions of Eminent Philosophers'' is a principal sou ...
,
Pliny the Elder Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman Empire, Roman author, Natural history, naturalist and Natural philosophy, natural philosopher, and naval and army commander of the early Roman Empire, and a friend of t ...
, and
Plutarch Plutarch (; grc-gre, Πλούταρχος, ''Ploútarchos''; ; – after AD 119) was a Greek people, Greek Middle Platonism, Middle Platonist philosopher, historian, Biography, biographer, essayist, and priest at the Temple of Apollo (D ...
. According to Hieronymus, historically quoted by
Diogenes Laërtius Diogenes Laërtius ( ; grc-gre, Διογένης Λαέρτιος, ; ) was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving ''Lives and Opinions of Eminent Philosophers'' is a principal sou ...
, Thales found the height of pyramids by comparison between the lengths of the shadows cast by a person and by the pyramids. Due to the variations among testimonies, such as the "story of the sacrifice of an ox on the occasion of the discovery that the angle on a diameter of a circle is a right angle" in the version told by Diogenes Laërtius being accredited to Pythagoras rather than Thales, some historians (such as D. R. Dicks) question whether such anecdotes have any historical worth whatsoever.


Water as a first principle

Thales' most famous philosophical position was his cosmological thesis, which comes down to us through a passage from
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical Greece, Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatet ...
's ''
Metaphysics Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of conscio ...
''. In the work Aristotle unequivocally reported Thales'
hypothesis A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can testable, test it. Scientists generally base scientific hypotheses on prev ...
about the nature of all
matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic partic ...
– that the originating principle of nature was a single material substance: water. Aristotle then proceeded to proffer a number of conjectures based on his own observations to lend some credence to why Thales may have advanced this idea (though Aristotle did not hold it himself). Aristotle laid out his own thinking about matter and form which may shed some light on the ideas of Thales, in ''
Metaphysics Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of conscio ...
'' 983 b6 8–11, 17–21. (The passage contains words that were later adopted by science with quite different meanings.) In this quote we see Aristotle's depiction of the problem of change and the definition of
substance Substance may refer to: * Matter, anything that has mass and takes up space Chemistry * Chemical substance, a material with a definite chemical composition * Drug substance ** Substance abuse, drug-related healthcare and social policy diagnosis o ...
. He asked if an object changes, is it the same or different? In either case how can there be a change from one to the other? The answer is that the substance "is saved", but acquires or loses different qualities (, the things you "experience"). Aristotle conjectured that Thales reached his conclusion by contemplating that the "nourishment of all things is moist and that even the hot is created from the wet and lives by it." While Aristotle's conjecture on why Thales held water as the originating principle of matter is his own thinking, his statement that Thales held it as water is generally accepted as genuinely originating with Thales and he is seen as an incipient matter-and-formist. Thales thought the Earth must be a flat disk which is floating in an expanse of water. Heraclitus Homericus states that Thales drew his conclusion from seeing moist substance turn into air, slime and earth. It seems likely that Thales viewed the Earth as solidifying from the water on which it floated and the oceans that surround it. Writing centuries later, Diogenes Laërtius also states that Thales taught "Water constituted (, 'stood under') the principle of all things."
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical Greece, Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatet ...
considered Thales’ position to be roughly the equivalent to the later ideas of Anaximenes, who held that everything was composed of
air The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing fo ...
. The 1870 book ''
Dictionary of Greek and Roman Biography and Mythology The ''Dictionary of Greek and Roman Biography and Mythology'' (1849, originally published 1844 under a slightly different title) is an encyclopedia/biographical dictionary. Edited by William Smith (lexicographer), William Smith, the dictionary s ...
'' noted:


Beliefs in divinity

According to Aristotle, Thales thought
lodestone Lodestones are naturally magnetization, magnetized pieces of the mineral magnetite. They are naturally occurring magnets, which can attract iron. The property of magnetism was first discovered in Ancient history, antiquity through lodeston ...
s had souls, because iron is attracted to them (by the force of
magnetism Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particles ...
). Aristotle defined the
soul In many religious and philosophical traditions, there is a belief that a soul is "the immaterial aspect or essence of a human being". Etymology The Modern English noun '':wikt:soul, soul'' is derived from Old English ''sāwol, sāwel''. The ea ...
as the principle of life, that which imbues the matter and makes it live, giving it the animation, or power to act. The idea did not originate with him, as the Greeks in general believed in the distinction between mind and matter, which was ultimately to lead to a distinction not only between body and soul but also between matter and energy. If things were alive, they must have souls. This belief was no innovation, as the ordinary ancient populations of the Mediterranean did believe that natural actions were caused by divinities. Accordingly, Aristotle and other ancient writers state that Thales believed that "all things were full of gods." In their zeal to make him the first in everything some said he was the first to hold the belief, which must have been widely known to be false. However, Thales was looking for something more general, a universal substance of mind. That also was in the polytheism of the times.
Zeus Zeus or , , ; grc, Δῐός, ''Diós'', label=Genitive case, genitive Aeolic Greek, Boeotian Aeolic and Doric Greek#Laconian, Laconian grc-dor, Δεύς, Deús ; grc, Δέος, ''Déos'', label=Genitive case, genitive el, Δίας, ''D ...
was the very personification of supreme
mind The mind is the set of faculties responsible for all mental Phenomenon, phenomena. Often the term is also identified with the phenomena themselves. These faculties include thought, imagination, memory, Will (philosophy), will, and Sensation (psy ...
, dominating all the subordinate manifestations. From Thales on, however, philosophers had a tendency to depersonify or objectify mind, as though it were the substance of animation per se and not actually a god like the other gods. The result was a total removal of mind from substance, opening the door to a non-divine principle of action. Classical thought, however, had proceeded only a little way along that path. Instead of referring to the person, Zeus, they talked about the great mind: The universal mind appears as a Roman belief in
Virgil Publius Vergilius Maro (; traditional dates 15 October 7021 September 19 BC), usually called Virgil or Vergil ( ) in English, was an ancient Rome, ancient Roman poet of the Augustan literature (ancient Rome), Augustan period. He composed three ...
as well: According to
Henry Fielding Henry Fielding (22 April 1707 – 8 October 1754) was an English novelist, irony writer, and dramatist known for earthy humour and satire. His comic novel ''The History of Tom Jones, a Foundling, Tom Jones'' is still widely appreciated. He and ...
(1775),
Diogenes Laërtius Diogenes Laërtius ( ; grc-gre, Διογένης Λαέρτιος, ; ) was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving ''Lives and Opinions of Eminent Philosophers'' is a principal sou ...
(1.35) affirmed that Thales posed "the independent pre-existence of God from all eternity, stating "that God was the oldest of all beings, for he existed without a previous cause even in the way of generation; that the world was the most beautiful of all things; for it was created by God."


Influences

Due to the scarcity of sources concerning Thales and the discrepancies between the accounts given in the sources that have survived, there is a scholarly debate over possible influences on Thales and the Greek mathematicians that came after him. Historian Roger L. Cooke points out that
Proclus Proclus Lycius (; 8 February 412 – 17 April 485), called Proclus the Successor ( grc-gre, Πρόκλος ὁ Διάδοχος, ''Próklos ho Diádokhos''), was a Greek philosophy, Greek Neoplatonism, Neoplatonist Philosophy, philosopher, ...
does not make any mention of Mesopotamian influence on Thales or Greek geometry, but "is shown clearly in Greek astronomy, in the use of sexagesimal system of measuring angles and in
Ptolemy Claudius Ptolemy (; grc-gre, wikt:Πτολεμαῖος, Πτολεμαῖος, ; la, Claudius Ptolemaeus; AD) was a mathematician, astronomer, astrologer, geographer, and music theorist, who wrote about a dozen scientific Treatise, treatis ...
's explicit use of Mesopotamian astronomical observations." Cooke notes that it may possibly also appear in the second book of
Euclid's Elements The ''Elements'' ( grc, Στοιχεῖα ''Stoikheîa'') is a mathematics, mathematical treatise consisting of 13 books attributed to the ancient Greek mathematics, Greek mathematician Euclid in Alexandria, Ptolemaic Egypt 300 BC. It is a colle ...
, "which contains geometric constructions equivalent to certain algebraic relations that are frequently encountered in the cuneiform tablets." Cooke notes "This relation, however, is controversial." Historian B.L. Van der Waerden is among those advocating the idea of Mesopotamian influence, writing "It follows that we have to abandon the traditional belief that the oldest Greek mathematicians discovered geometry entirely by themselves...a belief that was tenable only as long as nothing was known about
Babylonian mathematics Babylonian mathematics (also known as ''Assyro-Babylonian mathematics'') are the mathematics developed or practiced by the people of Mesopotamia, from the days of the early Sumerians to the centuries following the fall of Babylon in 539 BC. Babyl ...
. This in no way diminishes the stature of Thales; on the contrary, his genius receives only now the honour that is due to it, the honour of having developed a logical structure for geometry, of having introduced proof into geometry." Some historians, such as D. R. Dicks takes issue with the idea that we can determine from the questionable sources we have, just how influenced Thales was by Babylonian sources. He points out that while Thales is held to have been able to calculate an eclipse using a cycle called the "Saros" held to have been "borrowed from the Babylonians", "The Babylonians, however, did not use cycles to predict solar eclipses, but computed them from observations of the latitude of the moon made shortly before the expected syzygy." Dicks cites historian O. Neugebauer who relates that "No Babylonian theory for predicting solar eclipse existed at 600 B.C., as one can see from the very unsatisfactory situation 400 years later; nor did the Babylonians ever develop any theory which took the influence of geographical latitude into account." Dicks examines the cycle referred to as 'Saros' – which Thales is held to have used and which is believed to stem from the Babylonians. He points out that Ptolemy makes use of this and another cycle in his book ''Mathematical Syntaxis'' but attributes it to Greek astronomers earlier than
Hipparchus Hipparchus (; el, wikt:Ἵππαρχος, Ἵππαρχος, ''Hipparkhos'';  BC) was a Ancient astronomy, Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidenta ...
and not to Babylonians. Dicks notes Herodotus does relate that Thales made use of a cycle to predict the eclipse, but maintains that "if so, the fulfillment of the 'prediction' was a stroke of pure luck not science". He goes further joining with other historians (F. Martini, J.L. E. Dreyer, O. Neugebauer) in rejecting the historicity of the eclipse story altogether. Dicks links the story of Thales discovering the cause for a solar eclipse with Herodotus' claim that Thales discovered the cycle of the sun with relation to the solstices, and concludes "he could not possibly have possessed this knowledge which neither the Egyptians nor the Babylonians nor his immediate successors possessed." Josephus is the only ancient historian that claims Thales visited Babylonia. Herodotus wrote that the Greeks learnt the practice of dividing the day into 12 parts, about the ''polos'', and the
gnomon A gnomon (; ) is the part of a sundial that casts a shadow. The term is used for a variety of purposes in mathematics and other fields. History A painted stick dating from 2300 BC that was excavated at the astronomical site of Taosi is the ol ...
from the Babylonians. (The exact meaning of his use of the word ''polos'' is unknown, current theories include: "the heavenly dome", "the tip of the axis of the celestial sphere", or a spherical concave sundial.) Yet even Herodotus' claims on Babylonian influence are contested by some modern historians, such as L. Zhmud, who points out that the division of the day into twelve parts (and by analogy the year) was known to the Egyptians already in the second millennium, the gnomon was known to both Egyptians and Babylonians, and the idea of the "heavenly sphere" was not used outside of Greece at this time. Less controversial than the position that Thales learnt Babylonian mathematics is the claim he was influenced by Egyptians. Pointedly historian S. N. Bychkov holds that the idea that the base angles of an isosceles triangle are equal likely came from Egypt. This is because, when building a roof for a home – having a cross section be exactly an isosceles triangle isn't crucial (as it's the ridge of the roof that must fit precisely), in contrast a symmetric square pyramid cannot have errors in the base angles of the faces or they will not fit together tightly. Historian D.R. Dicks agrees that compared to the Greeks in the era of Thales, there was a more advanced state of mathematics among the Babylonians and especially the Egyptians – "both cultures knew the correct formulae for determining the areas and volumes of simple geometrical figures such as triangles, rectangles, trapezoids, etc.; the Egyptians could also calculate correctly the volume of the frustum of a pyramid with a square base (the Babylonians used an incorrect formula for this), and used a formula for the area of a circle...which gives a value for π of 3.1605—a good approximation." Dicks also agrees that this would have had an effect on Thales (whom the most ancient sources agree was interested in mathematics and astronomy) but he holds that tales of Thales' travels in these lands are pure myth. The ancient civilization and massive monuments of Egypt had "a profound and ineradicable impression on the Greeks". They attributed to Egyptians "an immemorial knowledge of certain subjects" (including geometry) and would claim Egyptian origin for some of their own ideas to try and lend them "a respectable antiquity" (such as the "Hermetic" literature of the Alexandrian period). Dicks holds that since Thales was a prominent figure in Greek history by the time of Eudemus but "nothing certain was known except that he lived in Miletus". A tradition developed that as "Milesians were in a position to be able to travel widely" Thales must have gone to Egypt. As Herodotus says Egypt was the birthplace of geometry he must have learnt that while there. Since he had to have been there, surely one of the theories on Nile Flooding laid out by Herodotus must have come from Thales. Likewise as he must have been in Egypt he had to have done something with the Pyramids – thus the tale of measuring them. Similar apocryphal stories exist of Pythagoras and Plato traveling to Egypt with no corroborating evidence. As the Egyptian and Babylonian geometry at the time was "essentially
arithmetic Arithmetic () is an elementary part of mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their chang ...
al", they used actual numbers and "the procedure is then described with explicit instructions as to what to do with these numbers" there was no mention of how the rules of procedure were made, and nothing toward a logically arranged corpus of generalized geometrical knowledge with analytical 'proofs' such as we find in the words of Euclid,
Archimedes Archimedes of Syracuse (;; ) was a Greek mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, ...
, and Apollonius." So even had Thales traveled there he could not have learnt anything about the theorems he is held to have picked up there (especially because there is no evidence that any Greeks of this age could use Egyptian hieroglyphics). Likewise until around the second century BC and the time of
Hipparchus Hipparchus (; el, wikt:Ἵππαρχος, Ἵππαρχος, ''Hipparkhos'';  BC) was a Ancient astronomy, Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidenta ...
(c. 190–120 BC) the Babylonian general division of the circle into 360 degrees and their sexagesimal system was unknown. Herodotus says almost nothing about Babylonian literature and science, and very little about their history. Some historians, like P. Schnabel, hold that the Greeks only learned more about Babylonian culture from
Berossus Berossus () or Berosus (; grc, Βηρωσσος, Bērōssos; possibly derived from akk, , romanized: , " Bel is his shepherd") was a Hellenistic In Classical antiquity, the Hellenistic period covers the time in History of the Mediterranea ...
, a Babylonian priest who is said to have set up a school in Cos around 270 BC (but to what extent this had in the field of geometry is contested). Dicks points out that the primitive state of Greek mathematics and astronomical ideas exhibited by the peculiar notions of Thales' successors (such as
Anaximander Anaximander (; grc-gre, Ἀναξίμανδρος ''Anaximandros''; ) was a Pre-Socratic philosophy, pre-Socratic Ancient Greek philosophy, Greek philosopher who lived in Miletus,"Anaximander" in ''Chambers's Encyclopædia''. London: George Newn ...
, Anaximenes,
Xenophanes Xenophanes of Colophon (; grc, wikt:Ξενοφάνης, Ξενοφάνης ὁ Κολοφώνιος ; c. 570 – c. 478 BC) was a Ancient Greece, Greek philosopher, theologian, poet, and critic of Homer from Ionia who travelled throughout the Gr ...
, and
Heraclitus Heraclitus of Ephesus (; grc-gre, wikt:Ἡράκλειτος, Ἡράκλειτος , "Glory of Hera"; ) was an Ancient Greece, ancient Greek Pre-Socratic philosophy, pre-Socratic philosopher from the city of Ephesus, which was then part of th ...
), which historian J. L. Heiberg calls "a mixture of brilliant intuition and childlike analogies", argues against the assertions from writers in late antiquity that Thales discovered and taught advanced concepts in these fields. John Burnet (1892) noted According to the 10th-century Byzantine encyclopedia ''
Suda The ''Suda'' or ''Souda'' (; grc-x-medieval, Σοῦδα, Soûda; la, Suidae Lexicon) is a large 10th-century Byzantine The Byzantine Empire, also referred to as the Eastern Roman Empire or Byzantium, was the continuation of the Roman ...
'', Thales had been the "teacher and kineman" of Anaximander. Nicholas Molinari has recently argued for an important Greek influence on Thales' idea of the ''archai'', namely, the archaic water deity Acheloios, who was equated with water and worshipped in Miletos during Thales' life. He argues that Thales, as a sage and world traveler, was exposed to many mythologies and religions, and while they all had some influence, his hometown Acheloios was the most essential. For evidence, he points to the fact that ''hydor'' meant specifically "fresh water," and that Acheloios was seen as a shape-shifter in myth and art, so able to become anything. He also points out that the rivers of the world were seen as the "sinews of Acheloios" in antiquity, and this multiplicity of deities is reflected in Thales' idea that "all things are full of gods."


Interpretations

In the long sojourn of philosophy, there has existed hardly a philosopher or historian of philosophy who did not mention Thales and try to characterize him in some way. He is generally recognized as having brought something new to human thought. Mathematics, astronomy, and medicine already existed. Thales added something to these different collections of knowledge to produce a universality, which, as far as writing tells us, was not in tradition before, but resulted in a new field. Ever since, interested persons have been asking what that new something is. Answers fall into (at least) two categories, the theory and the method. Once an answer has been arrived at, the next logical step is to ask how Thales compares to other philosophers, which leads to his classification (rightly or wrongly).


Theory

The most natural epithets of Thales are " materialist" and " naturalist", which are based on ousia and physis. The
Catholic Encyclopedia The ''Catholic Encyclopedia: An International Work of Reference on the Constitution, Doctrine, Discipline, and History of the Catholic Church'' (also referred to as the ''Old Catholic Encyclopedia'' and the ''Original Catholic Encyclopedia'') i ...
notes that Aristotle called him a physiologist, with the meaning "student of nature." On the other hand, he would have qualified as an early
physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate caus ...
, as did Aristotle. They studied corpora, "bodies", the medieval descendants of substances.


Russell

Most agree that Thales' stamp on thought is the unity of substance, hence
Bertrand Russell Bertrand Arthur William Russell, 3rd Earl Russell, (18 May 1872 – 2 February 1970) was a British mathematician, philosopher, logician, and public intellectual. He had a considerable influence on mathematics, logic, set theory, linguistics, ar ...
: Russell was only reflecting an established tradition; for example:
Nietzsche Friedrich Wilhelm Nietzsche (; or ; 15 October 1844 – 25 August 1900) was a German philosopher, Prose poetry, prose poet, cultural critic, Philology, philologist, and composer whose work has exerted a profound influence on contemporary philo ...
, in his '' Philosophy in the Tragic Age of the Greeks'', wrote: This sort of materialism, however, should not be confused with deterministic materialism. Thales was only trying to explain the unity observed in the free play of the qualities. The arrival of uncertainty in the modern world made possible a return to Thales; for example, John Elof Boodin writes ("God and Creation"):


Boodin

Boodin defines an "emergent" materialism, in which the objects of sense emerge uncertainly from the substrate. Thales is the innovator of this sort of materialism.


Feldman

Later scholastic thinkers would maintain that in his choice of water Thales was influenced by Babylonian or Chaldean religion, that held that a god had begun creation by acting upon the pre-existing water. Historian Abraham Feldman holds this does not stand up under closer examination. In Babylonian religion the water is lifeless and sterile until a god acts upon it, but for Thales water itself was divine and creative. He maintained that "All things are full of gods", and to understand the nature of things was to discover the secrets of the deities, and through this knowledge open the possibility that one could be greater than the grandest Olympian. Feldman points out that while other thinkers recognized the wetness of the world "none of them was inspired to conclude that everything was ultimately aquatic." He further points out that Thales was "a wealthy citizen of the fabulously rich Oriental port of Miletus...a dealer in the staples of antiquity, wine and oil...He certainly handled the shell-fish of the Phoenicians that secreted the dye of imperial purple." Feldman recalls the stories of Thales measuring the distance of boats in the harbor, creating mechanical improvements for ship navigation, giving an explanation for the
flooding of the Nile The flooding of the Nile has been an important natural cycle in Egypt since Ancient Egypt, ancient times. It is celebrated by Egyptians as an annual holiday for two weeks starting August 15, known as ''Wafaa El-Nil''. It is also celebrated in the ...
(vital to Egyptian agriculture and Greek trade), and changing the course of the river Halys so an army could ford it. Rather than seeing water as a barrier Thales contemplated the Ionian yearly religious gathering for athletic ritual (held on the promontory of Mycale and believed to be ordained by the ancestral kindred of Poseidon, the god of the sea). He called for the Ionian mercantile states participating in this ritual to convert it into a democratic federation under the protection of Poseidon that would hold off the forces of pastoral Persia. Feldman concludes that Thales saw "that water was a revolutionary leveler and the elemental factor determining the subsistence and business of the world" and "the common channel of states." Feldman considers Thales' environment and holds that Thales would have seen tears, sweat, and blood as granting value to a person's work and the means how life giving commodities travelled (whether on bodies of water or through the sweat of slaves and pack-animals). He would have seen that minerals could be processed from water such as life-sustaining salt and gold taken from rivers. He would’ve seen fish and other food stuffs gathered from it. Feldman points out that Thales held that the
lodestone Lodestones are naturally magnetization, magnetized pieces of the mineral magnetite. They are naturally occurring magnets, which can attract iron. The property of magnetism was first discovered in Ancient history, antiquity through lodeston ...
was alive as it drew metals to itself. He holds that Thales "living ever in sight of his beloved sea" would see water seem to draw all "traffic in wine and oil, milk and honey, juices and dyes" to itself, leading him to "a vision of the universe melting into a single substance that was valueless in itself and still the source of wealth." Feldman concludes that for Thales "...water united all things. The social significance of water in the time of Thales induced him to discern through hardware and dry-goods, through soil and sperm, blood, sweat and tears, one fundamental fluid stuff...water, the most commonplace and powerful material known to him." This combined with his contemporary's idea of " spontaneous generation" allow us to see how Thales could hold that water could be divine and creative. Feldman points to the lasting association of the theory that "all whatness is wetness" with Thales himself, pointing out that Diogenes Laërtius speaks of a poem, probably a satire, where Thales is snatched to heaven by the sun.


Rise of theoretical inquiry

In the West, Thales represents a new kind of inquiring community as well.
Edmund Husserl , thesis1_title = Beiträge zur Variationsrechnung (Contributions to the Calculus of Variations) , thesis1_url = https://fedora.phaidra.univie.ac.at/fedora/get/o:58535/bdef:Book/view , thesis1_year = 1883 , thesis2_title ...
attempts to capture the new movement as follows. Philosophical man is a "new cultural configuration" based in stepping back from "pregiven tradition" and taking up a rational "inquiry into what is true in itself;" that is, an ideal of truth. It begins with isolated individuals such as Thales, but they are supported and cooperated with as time goes on. Finally the ideal transforms the norms of society, leaping across national borders.


Classification

The term "
Pre-Socratic Pre-Socratic philosophy, also known as early Greek philosophy, is ancient Greek philosophy before Socrates. Pre-Socratic philosophers were mostly interested in cosmology, the beginning and the substance of the universe, but the inquiries of thes ...
" derives ultimately from the philosopher Aristotle, who distinguished the early philosophers as concerning themselves with substance. Diogenes Laërtius on the other hand took a strictly geographic and ethnic approach. Philosophers were either Ionian or Italian. He used "Ionian" in a broader sense, including also the Athenian academics, who were not Pre-Socratics. From a philosophic point of view, any grouping at all would have been just as effective. There is no basis for an Ionian or Italian unity. Some scholars, however, concede to Diogenes' scheme as far as referring to an "Ionian" school. There was no such school in any sense. The most popular approach refers to a Milesian school, which is more justifiable socially and philosophically. They sought for the substance of phenomena and may have studied with each other. Some ancient writers qualify them as Milesioi, "of Miletus."


Influence on others

Thales had a profound influence on other Greek thinkers and therefore on Western history. Some believe
Anaximander Anaximander (; grc-gre, Ἀναξίμανδρος ''Anaximandros''; ) was a Pre-Socratic philosophy, pre-Socratic Ancient Greek philosophy, Greek philosopher who lived in Miletus,"Anaximander" in ''Chambers's Encyclopædia''. London: George Newn ...
was a pupil of Thales. Early sources report that one of Anaximander's more famous pupils,
Pythagoras Pythagoras of Samos ( grc, Πυθαγόρας ὁ Σάμιος, Pythagóras ho Sámios, Pythagoras the Samos, Samian, or simply ; in Ionian Greek; ) was an ancient Ionians, Ionian Ancient Greek philosophy, Greek philosopher and the eponymou ...
, visited Thales as a young man, and that Thales advised him to travel to Egypt to further his philosophical and mathematical studies. Many philosophers followed Thales' lead in searching for explanations in
nature Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...
rather than in the supernatural; others returned to supernatural explanations, but couched them in the language of philosophy rather than of myth or of
religion Religion is usually defined as a social- cultural system of designated behaviors and practices, morals, beliefs, worldviews, texts, sanctified places, prophecies, ethics, or religious organization, organizations, that generally relates hu ...
. Looking specifically at Thales' influence during the pre-Socratic era, it is clear that he stood out as one of the first thinkers who thought more in the way of ''
logos ''Logos'' (, ; grc, wikt:λόγος, λόγος, lógos, lit=word, discourse, or reason) is a term used in Western philosophy, psychology and rhetoric and refers to the appeal to reason that relies on logic or reason, inductive and deductive ...
'' than '' mythos''. The difference between these two more profound ways of seeing the world is that ''mythos'' is concentrated around the stories of holy origin, while ''logos'' is concentrated around the argumentation. When the mythical man wants to explain the world the way he sees it, he explains it based on gods and powers. Mythical thought does not differentiate between things and persons and furthermore it does not differentiate between nature and culture. The way a ''logos'' thinker would present a world view is radically different from the way of the mythical thinker. In its concrete form, ''logos'' is a way of thinking not only about individualism, but also the abstract. Furthermore, it focuses on sensible and continuous argumentation. This lays the foundation of
philosophy Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied or resolved. Some ...
and its way of explaining the world in terms of abstract argumentation, and not in the way of gods and mythical stories.


Reliability of sources

Because of Thales' elevated status in Greek culture, an intense interest and admiration followed his reputation. Due to this following, the oral stories about his life were open to amplification and historical fabrication, even before they were written down generations later. Most modern dissension comes from trying to interpret what we know, in particular, distinguishing legend from fact.


Chronological classification

Historian D.R. Dicks and other historians divide the ancient sources about Thales into those before 320 BC and those after that year (including some such as
Proclus Proclus Lycius (; 8 February 412 – 17 April 485), called Proclus the Successor ( grc-gre, Πρόκλος ὁ Διάδοχος, ''Próklos ho Diádokhos''), was a Greek philosophy, Greek Neoplatonism, Neoplatonist Philosophy, philosopher, ...
writing in the 5th century C.E. and
Simplicius of Cilicia Simplicius of Cilicia Cilicia (); el, Κιλικία, ''Kilikía''; Middle Persian: ''klkyʾy'' (''Klikiyā''); Parthian language, Parthian: ''kylkyʾ'' (''Kilikiyā''); tr, Kilikya). is a geographical region in southern Anatolia in Turkey, e ...
in the 6th century C.E., who wrote nearly a millennium after his era). The first category includes
Herodotus Herodotus ( ; grc, , }; BC) was an ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided in ...
,
Plato Plato ( ; grc-gre, wikt:Πλάτων, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greeks, Greek philosopher born in Athens during the Classical Greece, Classical period in Ancient Greece. He founded the Platonist school of thou ...
,
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical Greece, Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatet ...
,
Aristophanes Aristophanes (; grc, Ἀριστοφάνης, ; c. 446 – c. 386 BC), son of Philippus, of the deme Kydathenaion ( la, Cydathenaeum), was a comedy, comic playwright or comedy-writer of Classical Athens, ancient Athens and a poet of Ancient G ...
, and
Theophrastus Theophrastus (; grc-gre, Θεόφραστος ; c. 371c. 287 BC), a Greek philosopher and the successor to Aristotle in the Peripatetic school. He was a native of Eresos in Lesbos Island, Lesbos.Gavin Hardy and Laurence Totelin, ''Ancient Bota ...
among others. The second category includes
Plautus Titus Maccius Plautus (; c. 254 – 184 BC), commonly known as Plautus, was a Ancient Rome, Roman playwright of the Old Latin period. His comedy, comedies are the earliest Latin literature, Latin literary works to have survived in their entiret ...
, Aetius,
Eusebius Eusebius of Caesarea (; grc-gre, Εὐσέβιος ; 260/265 – 30 May 339), also known as Eusebius Pamphilus (from the grc-gre, Εὐσέβιος τοῦ Παμφίλου), was a Greeks, Greek historian of Christianity, exegete, and C ...
,
Plutarch Plutarch (; grc-gre, Πλούταρχος, ''Ploútarchos''; ; – after AD 119) was a Greek people, Greek Middle Platonism, Middle Platonist philosopher, historian, Biography, biographer, essayist, and priest at the Temple of Apollo (D ...
,
Josephus Flavius Josephus (; grc-gre, Ἰώσηπος, ; 37 – 100) was a first-century Roman Jews, Romano-Jewish historian and military leader, best known for ''The Jewish War'', who was born in Jerusalem—then part of Judea (Roman province), Roman ...
,
Iamblichus Iamblichus (; grc-gre, Ἰάμβλιχος ; Aramaic: 𐡉𐡌𐡋𐡊𐡅 ''Yamlīḵū''; ) was a Syrians, Syrian Neoplatonism, neoplatonic philosopher of Arabs, Arabic origin. He determined a direction later taken by neoplatonism. Iamblich ...
,
Diogenes Laërtius Diogenes Laërtius ( ; grc-gre, Διογένης Λαέρτιος, ; ) was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving ''Lives and Opinions of Eminent Philosophers'' is a principal sou ...
,
Theon of Smyrna Theon of Smyrna ( el, Θέων ὁ Σμυρναῖος ''Theon ho Smyrnaios'', ''gen.'' Θέωνος ''Theonos''; fl. 100 CE) was a Greece, Greek philosopher and mathematician, whose works were strongly influenced by the Pythagoras, Pythagorean sch ...
,
Apuleius Apuleius (; also called Lucius Apuleius Madaurensis; c. 124 – after 170) was a Numidians, Numidian Latin-language prose writer, Platonist philosopher and rhetorician. He lived in the Roman Empire, Roman Numidia (Roman province), province of Nu ...
,
Clement of Alexandria Titus Flavius Clemens, also known as Clement of Alexandria ( grc , Κλήμης ὁ Ἀλεξανδρεύς; – ), was a Christian theology, Christian theologian and philosopher who taught at the Catechetical School of Alexandria. Among his pu ...
,
Pliny the Elder Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman Empire, Roman author, Natural history, naturalist and Natural philosophy, natural philosopher, and naval and army commander of the early Roman Empire, and a friend of t ...
, and
John Tzetzes John Tzetzes ( grc-gre, Ἰωάννης Τζέτζης, Iōánnēs Tzétzēs; c. 1110, Constantinople – 1180, Constantinople) was a Byzantine Empire, Byzantine poet and Speculative grammarians, grammarian who is known to have lived at Constantino ...
among others.


Earliest sources

The earliest sources on Thales (living before 320 BC) are often the same for the other Milesian philosophers (
Anaximander Anaximander (; grc-gre, Ἀναξίμανδρος ''Anaximandros''; ) was a Pre-Socratic philosophy, pre-Socratic Ancient Greek philosophy, Greek philosopher who lived in Miletus,"Anaximander" in ''Chambers's Encyclopædia''. London: George Newn ...
, and Anaximenes). These sources were either roughly contemporaneous (such as
Herodotus Herodotus ( ; grc, , }; BC) was an ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided in ...
) or lived within a few hundred years of his passing. Moreover, they were writing from an oral tradition that was widespread and well known in the Greece of their day.


Latter sources

The latter sources on Thales are several "ascriptions of commentators and compilers who lived anything from 700 to 1,000 years after his death" which include "anecdotes of varying degrees of plausibility" and in the opinion of some historians (such as D. R. Dicks) of "no historical worth whatsoever". Dicks points out that there is no agreement "among the 'authorities' even on the most fundamental facts of his life—e.g. whether he was a Milesian or a Phoenician, whether he left any writings or not, whether he was married or single—much less on the actual ideas and achievements with which he is credited."


Comparison of the two source groups

Contrasting the work of the more ancient writers with those of the later, Dicks points out that in the works of the early writers Thales and the other men who would be hailed as "the Seven Sages of Greece" had a different reputation than that which would be assigned to them by later authors. Closer to their own era, Thales,
Solon Solon ( grc-gre, wikt:Σόλων, Σόλων;  BC) was an History of Athens, Athenian statesman, constitutional lawmaker and poet. He is remembered particularly for his efforts to legislate against political, economic and moral decline in A ...
, Bias of Priene,
Pittacus of Mytilene Pittacus (; grc-gre, wikt:Πίττακος, Πιττακός; 640 – 568 BC) was an ancient Mytilenean military general and one of the Seven Sages of Greece. Biography Pittacus was a native of Mytilene and son of Hyrradius. He became a Mytilen ...
and others were hailed as "essentially practical men who played leading roles in the affairs of their respective states, and were far better known to the earlier Greeks as lawgivers and statesmen than as profound thinkers and philosophers." For example, Plato praises him (coupled with Anacharsis) for being the originator of the potter's wheel and the anchor. Only in the writings of the second group of writers (working after 320 BC) do "we obtain the picture of Thales as the pioneer in Greek scientific thinking, particularly in regard to mathematics and astronomy which he is supposed to have learnt about in Babylonia and Egypt." Rather than "the earlier tradition herehe is a favourite example of the intelligent man who possesses some technical 'know how'...the later doxographers uch_as_Dicaearchus_in_the_latter_half_of_the_fourth_century_BC.html" ;"title="Dicaearchus.html" ;"title="uch as Dicaearchus">uch as Dicaearchus in the latter half of the fourth century BC">Dicaearchus.html" ;"title="uch as Dicaearchus">uch as Dicaearchus in the latter half of the fourth century BCfoist on to him any number of discoveries and achievements, in order to build him up as a figure of superhuman wisdom."


Problem suggested by Dicks

Dicks points out a further problem arises in the surviving information on Thales, for rather than using ancient sources closer to the era of Thales, the authors in later antiquity ("epitomators, excerptors, and compilers") actually "preferred to use one or more intermediaries, so that what we actually read in them comes to us not even at second, but at third or fourth or fifth hand. Obviously, this use of intermediate sources, copied and recopied from century to century, with each writer adding additional pieces of information of greater or less plausibility from his own knowledge, provided a fertile field for errors in transmission, wrong ascriptions, and fictitious attributions". Dicks points out that "certain doctrines that later commentators invented for Thales...were then accepted into the biographical tradition" being copied by subsequent writers who were then cited by those coming after them "and thus, because they may be repeated by different authors relying on different sources, may produce an illusory impression of genuineness."


Aristotle

Doubts even exist when considering the philosophical positions held to originate in Thales "in reality these stem directly from Aristotle's own interpretations which then became incorporated in the doxographical tradition as erroneous ascriptions to Thales". (The same treatment was given by Aristotle to Anaxagoras.) Most philosophic analyses of the philosophy of Thales come from
Aristotle Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical Greece, Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatet ...
, a professional philosopher, tutor of
Alexander the Great Alexander III of Macedon ( grc, wikt:Ἀλέξανδρος, Ἀλέξανδρος, Alexandros; 20/21 July 356 BC – 10/11 June 323 BC), commonly known as Alexander the Great, was a king of the Ancient Greece, ancient Greek kingdom of Maced ...
, who wrote 200 years after Thales' death. Aristotle, judging from his surviving books, does not seem to have access to any works by Thales, although he probably had access to works of other authors about Thales, such as
Herodotus Herodotus ( ; grc, , }; BC) was an ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided in ...
, Hecataeus,
Plato Plato ( ; grc-gre, wikt:Πλάτων, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greeks, Greek philosopher born in Athens during the Classical Greece, Classical period in Ancient Greece. He founded the Platonist school of thou ...
etc., as well as others whose work is now extinct. It was Aristotle's express goal to present Thales' work not because it was significant in itself, but as a prelude to his own work in natural philosophy. Geoffrey Kirk and
John Raven John Earle Raven (13 December 1914 – 5 March 1980) was an English people, English classical scholar, notable for his work on presocratic philosophy, and amateur botanist. Early life and education John Raven was born on 13 December 1914 in Ca ...
, English compilers of the fragments of the Pre-Socratics, assert that Aristotle's "judgments are often distorted by his view of earlier philosophy as a stumbling progress toward the truth that Aristotle himself revealed in his physical doctrines." There was also an extensive oral tradition. Both the oral and the written were commonly read or known by all educated men in the region. Aristotle's philosophy had a distinct stamp: it professed the theory of matter and form, which modern scholastics have dubbed hylomorphism. Though once very widespread, it was not generally adopted by rationalist and modern science, as it mainly is useful in
metaphysical Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of conscio ...
analyses, but does not lend itself to the detail that is of interest to modern science. It is not clear that the theory of matter and form existed as early as Thales, and if it did, whether Thales espoused it. While some historians, like B. Snell, maintain that Aristotle was relying on a pre-Platonic written record by
Hippias Hippias of Elis (city), Elis (; el, Ἱππίας ὁ Ἠλεῖος; late 5th century BC) was a Ancient Greece, Greek sophist, and a contemporary of Socrates. With an assurance characteristic of the later sophists, he claimed to be regarded as a ...
rather than oral tradition, this is a controversial position. Representing the scholarly consensus Dicks states that "the tradition about him even as early as the fifth century B.C., was evidently based entirely on hearsay....It would seem that already by Aristotle's time the early Ionians were largely names only to which popular tradition attached various ideas or achievements with greater or less plausibility". He points out that works confirmed to have existed in the sixth century BC by Anaximander and Xenophanes had already disappeared by the fourth century BC, so the chances of Pre-Socratic material surviving to the age of Aristotle is almost nil (even less likely for Aristotle's pupils Theophrastus and Eudemus and less likely still for those following after them).


Diogenes Laërtius

The main secondary source concerning the details of Thales' life and career is
Diogenes Laërtius Diogenes Laërtius ( ; grc-gre, Διογένης Λαέρτιος, ; ) was a biographer of the Greek philosophers. Nothing is definitively known about his life, but his surviving ''Lives and Opinions of Eminent Philosophers'' is a principal sou ...
, "'' Lives of Eminent Philosophers''". This is primarily a biographical work, as the name indicates. Compared to Aristotle, Diogenes is not much of a philosopher. He is the one who, in the Prologue to that work, is responsible for the division of the early philosophers into "Ionian" and "Italian", but he places the Academics in the Ionian school and otherwise evidences considerable disarray and contradiction, especially in the long section on forerunners of the "Ionian School". Diogenes quotes two letters attributed to Thales, but Diogenes wrote some eight centuries after Thales' death and that his sources often contained "unreliable or even fabricated information", hence the concern for separating fact from legend in accounts of Thales. It is due to this use of hearsay and a lack of citing original sources that leads some historians, like Dicks and Werner Jaeger, to look at the late origin of the traditional picture of Pre-Socratic philosophy and view the whole idea as a construct from a later age, "the whole picture that has come down to us of the history of early philosophy was fashioned during the two or three generations from Plato to the immediate pupils of Aristotle".


See also

* Know thyself * Material monism * Plato's Academy mosaic


Notes


References

* (1991 pbk ed.
2011 3rd edition
*

* *
Herodotus Herodotus ( ; grc, , }; BC) was an ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided in ...
, '' Histories'', A. D. Godley (translator), Cambridge: Harvard University Press, 1920;
Online version at Perseus
* Hans Joachim Störig, ''Kleine Weltgeschichte der Philosophie''. Fischer, Frankfurt/M. 2004, . * * *
Pliny the Elder Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman Empire, Roman author, Natural history, naturalist and Natural philosophy, natural philosopher, and naval and army commander of the early Roman Empire, and a friend of t ...
, '' The Natural History'' (eds. John Bostock, M.D., F.R.S. H.T. Riley, Esq., B.A.) London. Taylor and Francis. (1855)
Online version
at the Perseus Digital Library. * *


Further reading

* * * * * Priou, Alex (2016).
The Origin and Foundations of Milesian Thought
" ''The Review of Metaphysics'' 70, 3–31. *


External links



* ttps://mathshistory.st-andrews.ac.uk/Biographies/Thales/ Thales of MiletusMacTutor History of Mathematics
Thales' Theorem – Math Open Reference
(with interactive animation)

(with extensive bibliography)

Life, Work and Testimonies by Giannis Stamatellos
Thales Fragments
{{Authority control 6th-century BC Greek people 6th-century BC philosophers 620s BC births 540s BC deaths Ancient Greek astronomers Ancient Greek geometers Ancient Greek metaphysicians Ancient Greek physicists Ancient Milesians Epistemologists Founders of philosophical traditions Metaphilosophers Metaphysicians Metaphysics writers Moral philosophers Natural philosophers Ontologists Philosophers of ancient Ionia Philosophers of education Philosophers of ethics and morality Philosophers of mathematics Philosophers of mind Philosophers of science Presocratic philosophers Seven Sages of Greece 6th-century BC mathematicians