Anaximenes (c. 585 – 525 B.C)


Anaximenes (c. 585 – 525 B.C.) was an early Pre-Socratic philosopher from the Greek city of Miletus in Ionia(modern-day Turkey). He was a key figure in the Milesian School, a friend and pupil of Anaximander and he continued the Milesians’ philosophical inquiries into the “archê” or first principle of the universe (which Anaximenes deemed to be air), and sought to give a quasi-scientific explanation of the world.

In the physical sciences, Anaximenes was the first Greek to distinguish clearly between planets and stars, and he used his principles to account for various natural phenomena, such as thunder and lightning, rainbows, earthquakes, etc.


Nothing is known of his life of Anaximenes (pronounced an-ax-IM-en-ees), other than that he was the son of Eurystratos of Miletus, and was the pupil or companion of Anaximander. Some say that he was also a pupil of Parmenides of Elea, although this seems unlikely. He lived for at least part of his life under Persian rule, and so he may have witnessed the Ionian rebellion against Greek occupation. There is some evidence from letters that he was in communication with Pythagoras, although any influence on Pythagoras’ philosophical development was probably minor (other than the desire to explain the world in non-mythological terms).


According to Diogenes Laërtius (a biographer of the Greek philosophers, who lived in the 2nd or 3rd Century A.D.), Anaximenes wrote his philosophical views in a book, which survived well into the Hellenistic period, although nothing now remains of this.

Like the other Milesian philosophers before him, Anaximenes’ main concern was to indentify the single source of all things in the universe (Monism). Thales, the earliest Milesian, had taken this to be water. His pupil Anaximander refined this somewhat, arguing that no single element could adequately explain all of the opposites found in nature, and propounded the solution of an endless, unlimited primordial mass which he called “apeiron”.

Anaximenes arguably took a step backwards by revisiting the notion that a single element was indeed the source of all things, and that element he deemed to be air(actually the Greek word “aer” also denotes “mist” or “vapour” as well as the normal air we breathe). He held that, at one time, everything was air, and that, even now, everything is air at different degrees of density. Since air is infinite and perpetually in motion, it can produce all things without being actually produced by anything.

Under the influence of heat (which expands it) and of cold (which contracts it), and the associated processes of rarefaction (air separating) and condensation (air coming together), air gradually gives rise to the several phases of existence and all the materials of the organized world. Anaximenes believed that air came in threadswhich came together by a process called “felting”, analogous to the process by which wool is compressed to make felt. Thus, very close air was a solid, less close a liquid, etc.

In this way, therefore, Anaximenes used natural processes familiar from everyday experience to account for material change and, in this respect at least, his theory was an advance over those of Thales and Anaximander.

According to Anaximenes, the earth is a broad disk, floating on the circumambient air. The sun and stars, he held, were formed by the same processes of condensation and rarefaction, and the flaming nature of these bodies is merely due to the velocity of their motions. He also used his principles to account for various natural phenomena: thunder and lightning result from wind breaking out of clouds; rainbows are the result of the rays of the sun falling on clouds; earthquakesare caused by the cracking of the earth when it dries out after being moistened by rains; hail is a result of frozen rainwater; etc.

Anaximenes also equated the first material principle with the divine, so that effectively “air is God”, both being infinite and eternal. Thus, the pantheon of Greek gods were merely derivations of the truly divine, air. Similarly, the souls of individuals were also composed of air (or breath), and hold us together in the same way as air encompasses the entire world.


Anaximander (c. 610 – 546 B.C)


Anaximander (c. 610 – 546 B.C.) was an early Pre-Socratic philosopher from the Greek city of Miletus in Ionia (modern-day Turkey). He was a key figure in the Milesian School, as a student of Thales and teacher of Anaximenes and Pythagoras.

He was an early proponent of science, and is sometimes considered to be the first true scientist, and to have conducted the earliest recorded scientific experiment. He is often considered the founder of astronomy, and he tried to observe and explain different aspects of the universe and its origins, and to describe the mechanics of celestial bodies in relation to the Earth. He made important contributions to cosmology, physics, geometry, meteorology and geography as well as to Metaphysics.


Anaximander was born in the Greek city of Miletus (on the Ionian coast of modern-day Turkey) in about 610 B.C., the son of Praxiades, but little else is known of his life.

According to Diogenes Laërtius (a biographer of the Greek philosophers, who lived in the 2nd or 3rd Century A.D.), he was a pupil of Thales (founder of the Milesian School of philosophy, and possibly also Anaximander’s uncle), and succeeded him as master of the school, where his work influenced Anaximenes and Pythagoras


Although he was among the earliest philosophers in the Western world to have actually written down his studies, only one fragment of his work remains and, by the time of Plato, his philosophy was apparently almost forgotten.

At a time when the Pre-Socratics were pursuing various forms of Monism and searching for the one element that constitutes all things (each had a different solution to the identity of this element: water for Thalesair for Anaximenes, firefor Heraclitus), Anaximander argued that neither water nor any of the other candidates can embrace all of the opposites found in nature (e.g. water can only be wet, never dry) and therefore cannot be the one primary substance or first principle of the universe.

He judged that, although not directly perceptible to us, the only substance which could explain all the opposites he saw around him, is what he called “apeiron”(variously translated as “the infinite”, “the boundless”, etc), an endless, unlimited primordial mass, subject to neither old age nor decay, that perpetually yielded fresh materials from which everything we perceive is derived. The Universe originates in the separation of opposites in this primordial matter, and dying things are merely returning to the boundless element from which they came. He saw the universe as a kind of organism, supported by “pneuma” (cosmic breath).

Anaximander is sometimes called the “Father of Cosmology” and the founder of astronomy for his bold use of non-mythological explanations of physical processes. He was the first to conceive a mechanical model of the world, in which the Earth floats very still in the centre of the infinite, not supported by anything. He envisioned the Earth as a cylinder with a height one-third of its diameter, the flat top forming the inhabited world, surrounded by a circular oceanic mass. This theory allowed for the concept that celestial bodies could pass under or around it, and provided a better explanation than Thales’ claim of a world floating on water (what would contain this ocean?).

Anaximander was the first astronomer to consider the Sun as a huge mass (and therefore to realize how far from Earth it might be), and the first to present a system where the celestial bodies turned at different distances. He built a celestial sphere, and his work on astronomy shows that he must have observed the inclination of the celestial sphere in relation to the plane of the Earth to explain the seasons. Anaximander also speculated on the plurality of worlds, which places him close to the Atomists and the Epicureans who, more than a century later, also claimed that an infinity of worlds appeared and disappeared.

Some consider Anaximander the earliest proponent of evolution (even though he had no theory of natural selection). Noting the existence of fossils, he claimed that animals sprang out of the sea long ago, and he put forward the idea that humans had to spend part of this transition inside the mouths of big fish to protect themselves from the Earth’s climate, until they had time to adapt to the emergence of dry land.

His other interests were in mathematics (he explained some basic notions of geometry and introduced the sundial gnomon to Greece), meteorology (he attributed some phenomena, such as thunder and lightning, to the intervention of elements, rather than to divine causes, and he explained rain as a product of the humidity pumped up from Earth by the sun) and geography (he was probably the first to publish a map of the world, i.e. the entire inhabited land known to the ancient Greeks, rather than the local maps which had been produced in ancient times).

Thales of Miletus (c. 624 – 546 B.C)

Thales of miletus


Thales of Miletus (c. 624 – 546 B.C.) was an early Pre-Socratic philosopher, mathematician and astronomer from the Greek city of Miletus in Ionia (modern-day Turkey). He was one of the so-called Seven Sages of Greece, and many regard him as the first philosopher in the Western tradition.

He was the founder of the Milesian School of natural philosophy, and the teacher of Anaximander. He was perhaps the first subscriber to Materialist and Naturalism in trying to define the substance or substances of which all material objects were composed, which he identified as water.

His innovative search for a universality in the disciplines of mathematics, astronomy and philosophy have earned him the label the “first scientist”.


Thales (pronounced THAY-lees) was born in the Greek city of Miletus (on the Ionian coast of modern-day Turkey) in about 624 or 625 B.C. (an estimate based on his age at death). The 3rd Century A.D. historian Diogenes Laërtius reported that his parents were Examyas and Cleobulina of the noble Milesian family of Thelidae (and descended from Agenor and Cadmus of ancient Thebes, Greece), although other sources suggest that his parents may have been Phoenician (from the modern-day region of Lebanon, Israel and Syria).

Details of his life are sketchy and often contradictory. Some reports suggest that he married and had a son, Cybisthus (or Cybisthon) or possibly adopted a nephew of the same name, while other reports suggest that he never married. Some say that he left no writings; others that he wrote at least two works, “On the Solstice” and “On the Equinox” (neither have survived). Some anecdotes suggest that Thales was involved in business and politics, and at one point bought up all the olive pressesin Miletus after predicting a good harvest for a particular year (either to make money or merely to demonstrate that he could use his intelligence to enrich himself if he had wanted to).

His involvement in local politics is also rather anecdotal in nature, but Thales apparently impressed both sides of the ongoing conflict between the LydiansMedesand Persians over the fate of the region of Ionia, when he predicted an eclipse of the sun which brought fighting to a standstill. He was also reportedly involved in the negotiations which followed the hostilities, and managed to obtain favourable terms for Miletus.

Thales is said to have died of dehydration while watching a gymnastics contest in 546 or 547 B.C., at the age of 78 (although other reports have him living to the age of 90).


In retrospect is is difficult to separate history from legend, but he is usually considered one of the Seven Sages or Seven Wise Men of ancient Greece, a group of 7th and early 6th Century B.C. philosophers, statesmen and law-givers who became renowned in the following centuries for their wisdom. The aphorism “Know thyself” has been attributed to Thales (as well as to at least six other ancient Greek sages). Much of what we known of Thales’ philosophy has come down to us from Aristotle and so may be somewhat distorted by Aristotle‘s own views. Some sources say that he left no writings; others that he wrote at least two works, “On the Solstice” and “On the Equinox” (neither of which have survived).

The early Pre-Socratic philosophers (of which Thales was one of the very first) tried to define the substance or substances of which all material objects were composed (as do modern scientists even today, hence Thales is sometimes described as the first scientist). He searched for the “physis” (or nature) of objects that cause them to behave in their characteristic way. He was one of the first Western philosophers who attempted to find naturalistic explanations of the world (Naturalism or Materialism) without reference to supernatural or mythological explanations, such as the Greek anthropomorphic gods and heroes. He explained earthquakes, for example, by hypothesizing that the Earth floats on water and that earthquakes occur when the Earth is rocked by waves.

His most famous belief was his cosmological doctrine that water was the first principle (roughly equivalent to Anaximenes’ later idea that everything in the world was composed of air). He claimed that water was the origin of all things, that from which all things emerge and to which they return, and moreover that all things ultimately are water. He probably drew this conclusion from seeing moist substances turn into air, slime and earth, and he clearly viewed the Earth as solidifying from the water on which it floated and which surrounded it.

While considering the effects of magnetism and static electricity, he concluded that the power to move other things without the mover itself changing was a characteristic of “life”, so that a magnet and amber must therefore be alive in some way (in that they have animation or the power to act). If so, he argued, there is no difference between the living and the dead. If all things were alive, they must also have souls or divinities (a natural belief of his time), and the end result of this argument was an almost total removal of mind from substance, opening the door to an innovative non-divine principle of action.

Thales recognized a single transcendental God (Monism), who has neither beginning nor end, but who expresses himself through other gods (Polytheism). His idea of justice included both the letter of the law and the spirit of the law (e.g. adultery and perjury about it in court are equally bad). He had some common sense moral advice: that we should expect the same support from our children that we give to our parents; that we should not let talk influence us against those we have come to trust; and that we should not do ourselves that for which we blame others. He believed that a happy man was one who was “healthy in body, resourceful in soul and of a readily teachable nature”.

His political views were generally in favour of a benign tyranny, rather than democracy (which most thinkers of his time distrusted as an inefficient and unreliable system). He believed that men were naturally better than women, and that Greeks were better than barbarians (non-Greeks).

Thales was known for his theoretical and practical understanding (and innovative use) of geometry, especially triangles. He established what has become known as Thales’ Theorem, whereby if a triangle is drawn within a circle with the long side as a diameter of the circle then the opposite angle will always be a right angle (as well as some other related properties derived from this).

He was also an important innovator in astronomy, and he had an effective theory of the path of the sun from solstice to solstice and supposedly correctly predicted a solar eclipse. Some sources have attributed him with the “discovery” of the seasons of the year and the 365-day year (consistent with his determination of the solstices). While this may be an exaggeration, his questioning approach to the understanding of heavenly phenomena arguably marked the real beginning of Greek astronomy.