Home   Walendowski 1   Walendowski 2   Walendowski 3   Walendowski 4

George Walendowski



The Milesians were a Pre-Socratic School of Philosophy who were concerned with explaining the underlying principle that was responsible for everything. In other words, the Milesians were interested in a unity principle. They were not satisfied with mythological beliefs, but, instead, they relied on observation and reason.

Consequently, we might perhaps call the Ionian cosmologies instances of abstract materialism: we can already discern in them the notion of unity in difference and of difference as entering into unity: and this is a philosophic notion. In addition the Ionian[Milesians] thinkers were convinced of the reign of law in the universe... This conception of a law-governed universe, a universe that is no plaything of mere caprice or lawless spontaneity, no mere field for lawless and "egoistic" domination of one element over another, formed a basis for a scientific cosmology as opposed to fanciful mythology[1].

Therefore, the Milesians could be truly called the first philosophers since they relied on reason and empirical evidence[2]. The Milesian philosophers were Thales (c. 624-c. 546 B.C.) the founder of the Milesian School, Anaximander (c. 611-c. 546 B.C.) and Anaximenes (c. 585-c. 528 B.C.). Each of these philosophers had a different concept of what they considered to be the first principle of everything. Nevertheless, they all were interested in three fundamental questions[3]: "(1) What is the basic substance of the universe? (2) How does this basic substance give rise to the plurality of objects we observe around us? (3) How does the world maintain itself?"

Unfortunately, written records of the Milesian philosophers themselves are either non-existent or very small fragments have survived. Therefore, most of the information concerning these philosophers are found from other sources such as Aristotle. The Milesians presented ideas (explanations) on many topics. However, this essay will concentrate on some of the more important concepts of Thales, Anaximander and Anaximenes.


Thales' primary interests were in metaphysics, mathematics and astronomy[4]. Thales' beliefs can be summarized by the following: (1) the first principle of all things is water; (2) the gods are found in all things; and (3) motion is caused by the soul.

The first belief that is associated with Thales is that the primary principle of everything is water. In Book I (A).3 of the Metaphysics Aristotle points out that Thales proposed water as the first principle of all things and giving the possible reasons why Thales chose water. Aristotle states:

Of the first philosophers, most thought the principles which were of the nature of matter were the only principles of all things; that of which all things that are consist, and from which they first come to be, and into which they are finally resolved (the substance remaining, but changing in its modifications), this they say is the element and the principle of things, and therefore they think nothing is either generated or destroyed, since this sort of entity is always conserved...

Yet they do not all agree as to the number and the nature of these principles. Thales, the founder of this school of philosophy, says the principle is water (for which reason he declared that the earth rests on water), getting the notion perhaps from seeing that the nutriment of all things is moist, and that heat itself is generated from the moist and kept alive by it (and that from which they come to be is a principle of all things). He got this notion from this fact, and from the fact that the seeds of all things have a moist nature, and that water is the origin of the nature of moist things[5].

Besides Aristotle's possible reasons why Thales chose water as the first principle, another explanation has also been given for this. Specifically, "There is another possible reason that Thales concludes that water is the first material principle. Since it is only water that in ordinary experience human beings see being transformed in its three phases (solid, liquid and gas), perhaps Thales reasons that all things must be water. In other words, if nothing else is known to change phases of matter, then that which does, i.e., water must[be] the source of all other things"[6].

It is interesting to note that it is not certain as to what Thales really meant when he proposed water as the first principle (arche). In other words, did Thales believe that everything was made up of water to a certain degree, or did everything come from water originally, or did he believe that everything did come from water originally and at the same time that everything was made up of water[7]?

In the present age Thales' first principle of water seems to be absurd. However, it must be remembered that Thales was looking for a rational explanation from which everything evolved rather than accepting mythological explanations. Thales was the first Greek philosopher who theorized a principle of unity in a diverse world[8].

The basic underlying concept of Thales' first principle is not what he states as being the first principle (i.e. water) but by the very fact that a rational (reasoned) theory is being proposed. As Aristotle states in Book I (A).2 of the Metaphysics:

And the most exact of the sciences are those which deal most with first principles; for those which involve fewer principles are more exact than those which involve additional principles... But the science which investigates causes is also more capable of reaching, for the people who teach are those who tell the causes of each thing... for he who chooses to know for the sake of knowing will choose most readily that which is most truly knowledge, and such is the knowledge of that which is most knowable; and the first principles and causes are most knowable; for by reason of these, and from these, all other things are known...[9].

Thales has also been attributed with the beliefs that the gods are found in everything and that motion is caused by the soul. In Book I.5 of On the Soul[10] Aristotle states "that Thales came to the opinion that all things are full of gods" and the reason for this belief as Aristotle further points out is that "Certain thinkers say that soul is intermingled in the whole universe." In addition, Aristotle writes that the soul itself does not move but is the mover. Specifically, he says "But since knowing, perceiving, opining and further desiring, wishing, and generally all other modes of appetition, belong to soul, and the local movements of animals, and growth, maturity, and decay are produced by the soul..."[11]. In fact, Thales attributes a soul to magnets because magnets move iron. One can further elaborate on this by stating that magnets have both attracting and repelling forces of movements.

Consequently, Thales' beliefs that "all things are full of gods" and that motion is caused by the soul would seem to be consistent with his first principle of water. "Thales almost certainly identified water as something divine... and so everything in the world, as derivatives of water, would have a divine element to them...[Also] we might conjecture that the property of being motive (i.e. being alive) derives from having some share in divinity (a share which all objects might automatically posses simply because they derive from water)"[12].

Thales also had an interest in astronomy. For example, he is given credit for predicting a solar eclipse. It has been verified by modern astronomers that a solar eclipse did occur in the year 585 B.C. Furthermore, it is believed Thales was aware that the solar eclipse was the result of the moon being in front of the sun.

Thales, in addition, proposed two hypotheses relating to earth. In the first one Thales claimed that the earth was spherical.

There are several good reasons to accept that Thales envisaged the earth as spherical... First is the fact that during a solar eclipse, the shadow caused by the interposition of the earth between the sun and the moon is always convex; therefore the earth must be spherical. In other words, if the earth were a flat disk, the shadow cast during an eclipse would be elliptical. Second, Thales... would have observed that stars which are visible in a certain locality may not be visible further to the north or south, a phenomena which could be explained within the understanding of a spherical earth. Third, from mere observation the earth has the appearance of being curved[13].

The second hypothesis that Thales made in relation to earth is that the earth floats on water. Aristotle was critical of this assumption. In Book II.13 of On The Heavens he states:

Others say the earth rests upon water... It was supposed to stay still because it floated like wood and other similar substances, which are so constituted as to rest upon water but not upon air... It is not the nature of water, any more than of earth, to stay in mid-air: it must have something to rest upon. Again, as air is lighter than water, so is water than earth: how then can they think that the naturally lighter substance lies below the heavier? Again, if the earth as a whole is capable of floating upon water, that must obviously be the case with any part of it. But observation shows that this is not the case. Any piece of earth goes to the bottom, the quicker the larger it is[14].

The above criticism by Aristotle of Thales' "floating earth on water" hypothesis can have some counter-arguments. For example, by observation a person can see that cargo ships remain afloat and islands remain above water. Therefore, Thales may have concluded that earth was really lighter than water[15]. Aristotle did not address these issues (counter-arguments) in his criticism of Thales. Another counter-argument in defense of Thales concerns clearly understanding Thales' belief. In other words, some commentators have expressed the belief that there is a misinterpretation of Thales' actual claim which is that the world originates from water[16].

Besides what already has been presented in this essay, Thales has also been involved in the area of mathematics.

Five Euclidean theorems have been explicitly attributed to Thales...

Thales did not formulate proofs in the formal sense. What Thales did was to put forward certain propositions which, it seems, he could have 'proven' by induction: he observed the similar results of his calculations: he showed by repeated experiment that his propositions and theorems were correct, and if none of his calculations resulted in contrary outcomes, he probably felt justified in accepting his results as proof...

DEFINITION I.17: A diameter of the circle is a straight line drawn through the centre and terminated in both directions by the circumference of the circle; and such a straight line also bisects the circle (Proclus, 124)...

PROPOSITION I.5: In isosceles triangles the angles at the base are equal; and if the equal straight lines are produced further, the angles under the base will be equal (Proclus, 244)...

PROPOSITION I.15: 'If two straight lines cut one another, they make the vertical angles equal to one another' (Proclus, 298.12-13)...

PROPOSITION I.26: 'If two triangles have the two angles equal to two angles respectively, and one side equal to one side, namely, either the side adjoining the equal angles, or that subtending one of the equal angles, they will also have the remaining sides equal to the remaining sides and the remaining angle equal to the remaining angle' (Proclus, 347.13-16)... Thales applied this theorem to determine the height of a pyramid... Diogenes recorded that 'Hieronymus informs us that[Thales] measured the height of the pyramids by the shadow they cast, taking the observation at the hour when our shadow is of the same length as ourselves' (D.L.I.27)... He[Thales] introduced the concept of ratio...

PROPOSITION III.31: 'The angle in a semicircle is a right angle.' Diogenes Laertius (I.27) recorded: 'Pamphila states that, having learnt geometry from the Egyptians,[Thales] was the first to inscribe a right-angled triangle in a circle...[17].

This demonstrates Thales' mathematical prowess. Not only have five Euclidean theorems been attributed to Thales, but he has also been credited with measuring the height of the pyramids.


Anaximander's major interests were in metaphysics, astronomy, geometry and geography[18]. Like Thales, Anaximander believed that there was a first principle of everything. However, unlike Thales who said the first principle was water, Anaximander believed that the primary principle was apeiron (the boundless or limitless) which was not really defined by Anaximander. However, Anaximander did claim that the apeiron had no qualities of its own, and it was infinite and unobservable. The reason Anaximander postulated this concept was because he saw conflicts in proposing one element such as water. As Aristotle in Book III.5 of the Physics points out:

Nor can an infinite body be one and simple, whether it is, as some hold, a thing over and above the elements (from which they generate the elements) or is not thus qualified. There are some people who make this the infinite, and not air or water, in order that the other elements may not be annihilated by the element which is infinite. They have contrariety with each other — air is cold, water moist, fire hot; if one were infinite, the others by now would have ceased to be. As it is, they say, the infinite is different from them and is their source[19].

In relation to Aristotle's statement above, Gottlieb provides a justification for Anaximander's theory of "the boundless." Gottlieb points out that there was a problem with Thales' water principle which Anaximander tried to resolve with his "boundless" concept. Specifically, the problem was: how did fire come from water and was not extinguished[20]? What Anaximander proposed for opposites to appear was due to the apeiron causing separations to occur for their existences. However, this brings up the following problem:

The next obvious question to ask, of course, is how the opposites are related to the Unbounded. We know that they somehow come out of it, but does that mean that they were originally in it? There are several possibilities, two of which are ventured by Aristotle. The first possibility is that the Unbounded really is a mixture of all opposites, and the second is that the opposites are simply modifications of the Unbounded. If the first reading is correct, then the fact that the Unbounded possesses no qualities of its own seems threatened. In fact, the first reading makes it seem as if there is not a single physis[first principle], but rather an infinite number (i.e. every possible opposite)... The second reading is troubling for another reason: if the opposites are not within the Unbounded originally, it is entirely unclear how they ever arise from it[21].

One of the consequences of Anaximander's principle of "the boundless" is his theory of the earth within its place in the cosmos. Anaximander claimed that the earth floats in space in the middle of the cosmos. Anaximander further maintains that even though the earth floats freely in space without any support, it does not fall due to what Aristotle terms as 'indifference." In fact, Aristotle in Book II.13 of On The Heavens explains:

It is to these causes that most writers pay attention; but there are some, Anaximander, for instance, among the ancients, who say that the earth keeps its place because of its indifference. Motion upward and downward and sideways were all, they thought, equally inappropriate to that which is set at the centre and indifferently related to every extreme point; and to move in contrary directions at the same time was impossible: so it must needs remain still. This view is ingenious but not true. The argument would prove that everything which is put at the centre must stay there... For the argument applies equally to fire. Fire, if set at the centre, should stay there, like earth, since it will be indifferently related to every point on the extremity. Nevertheless it will move, as in fact it always does move when nothing stops it, away from the centre to the extremity[22].

In other words, Anaximander visualized the universe (cosmos) as being concentric circles (a sphere) with earth in the middle. Consequently, the earth, according to Anaximander, was equidistant from all points on the circles. Therefore, all these forces acted equally upon the earth resulting in the earth being "at rest" and preventing it from falling. One interesting aspect emanating from this type of explanation gave rise to what is known as the principle of sufficient reason which states that for anything to transpire requires a reason.


Anaximenes' primary interest was in metaphysics[23]. His first principle (arche) from which everything came was air. Consequently, he reverts back to Thales' one element as being the principle of everything which is unlike Anaximander's arche of the boundless. Apparently, Anaximenes was dissatisfied with Anaximander's undefined and unobservable first principle. However, Anaximenes did hold a similar view to Anaximander in that Anaximenes believed that the first principle was limitless. There was also another similarity between Anaximenes and Anaximander. "According to a trustworthy tradition, Anaximenes, like Anaximander, held the theory of successive alternations of world-creation and world-destruction"[24].

Anaximenes chose air as the first principle based on a quality/quantity relationship. In other words, air changed to other elements because of rarefaction and condensation. "Using two contrary processes of rarefaction and condensation, Anaximenes explains how air is part of a series of changes. Fire turns to air, air to wind, wind to cloud, cloud to water, water to earth and earth to stone. Matter can travel this path by being condensed, or the reverse path from stones to fire by being successively more rarefied"[25].

Anaximenes just does not haphazardly choose air as the first principle from which everything is derived. He provides evidence from observations to support his claim.

... Anaximenes provides us with evidence for the claim that rarefaction and condensation of air can give rise to qualitative changes. In particular, he provides us with evidence that condensation gives rise to coldness, and rarefaction to heat. His first piece of evidence comes from human breath. If we hold our lips far apart and[breathe] out, the resulting breath is hot. If, on the other hand, we purse our lips, forcing the air into a smaller space, the resulting breath is cool. As another confirming instance, Anaximenes points to water, snow, and ice. Water the most condensed form of the three, is warmest, ice coldest, and snow somewhere in between[26].

In similar fashion of his predecessors Anaximenes was also interested in explaining earth's relation in the cosmos. Unlike Thales who claimed that the earth floats on water and Anaximander who claimed that the earth was in the center of a circle equally distant from all its points, Anaximenes claimed that the earth was flat and floated on air. All three philosophers had the same objective of explaining why the earth did not fall because of the type of support it had. Just as in the cases of Thales and Anaximander, Aristotle also questioned Anaximenes' earth's air flotation theory. Aristotle in Book II.13 of On The Heavens states:

Anaximenes and Anaxogoras and Democritus give the flatness of the earth as the cause of its staying still... The same immobility, they say, is produced by the flatness of the surface which the earth presents to the air which underlies it (while the air, not having room enough to change its place rests on the compressed mass underneath)...

But suppose both the whirl and its flatness (the air beneath being withdrawn) cease to prevent the earth's motion, where will the earth move to then? Its movement to the centre was constrained, and its rest at the centre is due to constraint; but there must be some motion which is natural to it. Will this be upward motion or downward or what? It must have some motion; and if upward and downward motion are alike to it, and the air above the earth does not prevent upward movement, then no more could air below it prevent downward movement. For the same cause must necessarily have the same effect on the same thing[27].


The Milesian philosophers all had the same common objective in trying to understand what governed the universe (cosmos). Each philosopher had a different view of the first principle. Thales believed it was water, Anaximander thought it was the boundless (apeiron), and Anaximenes believed it was air.

In addition to being concerned about understanding what governed the universe, some of the Milesian philosophers were interested in mathematics and geography, and in explaining such natural occurrences as earthquakes, lightning and thunder, eclipses, and human evolution. Even though their explanations were not correct, the importance of the Milesian philosophers was their contribution to using observation (whenever possible) and reason to arrive at their explanations rather than accepting mythological explanations. The Milesians assumed there were laws that governed the cosmos which were not beyond human understanding[28].


1. Copleston, S.J., p. 21.

2. Vuletic.

3. SparkNotes Editors, p.2 ("Context").

4. Wikipedia, "Thales," p. 1.

5. Aristotle, Metaphysics, pp. 1555-1556.

6. "Thales," p. 3.

7. Gottlieb, p. 6.

8. Copleston, S.J., p. 23.

9. Aristotle, Metaphysics, p. 1554.

10. Aristotle, On The Soul, p. 655.

11. ibid.

12. SparkNotes Editors, p. 3 ("Thales of Miletus").

13. O'Grady, p. 8.

14. Aristotle, On The Heavens, p. 484.

15. O'Grady, p. 7.

16. SparkNotes Editors, p. 2 ("Thales of Miletus").

17. O'Grady, pp. 17-18.

18. Wikipedia, "Anaximander," p. 1.

19. Aristotle, Physics, p. 349.

20. Gottlieb, p.10.

21. SparkNotes Editors, p. 3 ("Anaximander of Miletus").

22. Aristotle, On The Heavens, p. 486.

23. Wikipedia, "Anaximenes of Miletus," p. 1.

24. Zeller, p. 31.

25. Graham, p. 2.

26. SparkNotes Editors, p. 2 ("Anaximenes of Miletus").

27. Aristotle, On The Heavens, pp. 484 and 485.

28. Gottlieb, p. 17.


Aristotle. Metaphysics, On The Heavens, On The Soul, Physics, in The Complete Works of Aristotle, the Revised Oxford Translation, Volumes One and Two (1991). Jonathan Barnes (ed.). Princeton, New Jersey: Princeton University Press.

Copleston, S.J., F. A History of Philosophy, Volume I, Image Books Edition (1985). New York: Doubleday, a division of Bantam Doubleday Dell Publishing Group, Inc.

Couprie, D.L. "Anaximander (c. 610-546 B.C.E.)." Internet Encyclopedia of Philosophy. Retrieved December 2014 at http://www.iep.utm.edu/anaximan/.

Gottlieb, A. The Dream of Reason: A History of Western Philosophy from the Greeks to the Renaissance (2000). New York: W.W. Norton & Company.

Graham, D.W. "Anaximenes (d. 528 B.C.E.)." Internet Encyclopedia of Philosophy. Retrieved December 2014 at http://www.iep.utm.edu/anaximen/.

O'Grady, P. "Thales of Miletus (c. 620 B.C.E.-c. 546 B.C.E.)." Internet Encyclopedia of Philosophy. Retrieved December 2014 at http://www.iep.utm.edu/thales/.

SparkNotes Editors. "SparkNote on Presocratics." SparkNotes LLC. n.d. Retrieved November 2014 at http://www.sparknotes.com/philosophy/presocratics/.

"Thales." Retrieved December 2014 at http://www.mycrandall.ca/courses/grphil/Thales.htm.

Vuletic, M.I. "The Milesians and the Origin of Philosophy." Retrieved December 2014 at www.vuletic.com/hume.

Wikipedia. "Anaximander." Retrieved December 2014 at http://en.wikipedia.org/wiki/Anaximander.

Wikipedia. "Anaximenes of Miletus." Retrieved December 2014 at http://en.wikipedia.org/wiki/Anaximenes_of_Miletus.

Wikipedia. "Thales." Retrieved December 2014 at http://en.wikipedia.org/wiki/Thales.

Zeller, E. Outlines of the History of Greek Philosophy (1980, Thirteenth Edition). New York: Dover Publications, Inc.