25. Thales of Miletus and Water

Thales of Miletus said that water was the basic element of the universe.
Thales of Miletus

As the story goes, Thales of Miletus, an astronomer among many other things, was walking along, gazing at the stars, not watching where he was going, when he fell into a well.1 A story like that is stereotypical of a philosopher who has his mind so set on lofty ideas, he loses touch with earthly things. With Thales, nothing could be further from the truth. 

In addition to being an astronomer and a philosopher, he was also an engineer, a meteorologist, and a mathematician.2 He was considered one of the seven sages of Greece.3 In one of his many claims to fame, he is said to have predicted a solar eclipse in 585 BC – something that was very difficult to do.4 Because of this eclipse, a 15-year battle between the Medians and the Lydians ended in a truce as both sides laid down their arms. 

He was born around 625 BC in Miletus in western Asia Minor.5 If Ionia was the center of philosophical development in Asia Minor (see previous post), then Miletus was the heart of philosophy in Ionia. Miletus was a very busy and prosperous city on the western coast of the Aegean Sea.6 The prosperity and stability of Miletus provided fertile ground for philosophy to develop. 

Thales eschewed worldly wealth and advancement, living a life of poverty. He was often ridiculed for this, but said nothing to defend himself. Instead, he just studied the weather.

One year, he predicted that there would be a glut of olives.7 Before this occurred, he rented all of the olive presses in Miletus. When the olive glut became apparent, he rented the olive presses back to the anxious owners at a handsome profit, proving that philosophers could make money if they wanted to. This prompted Aristotle to say, years later, “Thus he showed the world that philosophers could get rich if they liked, but their ambition is of another sort.” 

He displayed his engineering talents when King Croesus of Lydia hired him to find a way for his army to cross the Halys River without having to build a bridge.8 Thales had the army encamp on the river bank and dig a trench around them so that the river was split into two, thus lowering the overall height of the water and allowing the army to cross safely. 

Thales of Miletus, the First Philosopher

Of all his accomplishments, his greatest claim to fame was that of being the first philosopher.  In post 26, I mentioned how the poet Hesiod broke new ground in cosmology by compiling a comprehensive account of the origin of the kosmos – the Greek term for “universe.” He attributed the origin of the cosmos to the gods rather than naturalistic causes. 

Thales took this a step further and started looking for a naturalistic cause for the origin of the universe. As mentioned in post 26, the overall cause or origin of the universe was what the Greeks termed arche. Aristotle defines the arche as:

“that of which all existing things are composed and that from which they originally come to be and that into which they finally perish.”9

-Aristotle, Metaphysics [983b]

The arche is the primary or originating principle of the universe. Even though the concept of arche originated with Hesiod who attributed it to the gods, it was Thales and the other Presocratics who sought the arche in naturalistic causes. 

When the Greeks talked about origin, they did not mean something arising out of nothing, ex nihilo, as in the Judeo-Christian tradition. For them, matter was eternal and always existed.10 The question for Thales was what was the original or primary element of matter from which the other elements arose? In other words, which element was the arche of the cosmos? 

The contenders for the arche were what the Greeks considered the basic elements of the cosmos – earth, air, fire, and water.11 They believed that the elements could change into one another. So Thales tried to rationalize which of the elements was the originating principle.

There is evidence that Thales traveled to Egypt and possibly other places. He would have learned about the Nile and its annual cycle of flooding and recession.12 When the Nile flooded, the plant life decayed and decomposed, turning into methane, a flammable gas. Thus all of the four elements were present. The same phenomenon occurred with the Tigris and Euphrates Rivers in Mesopotamia as well as at the mouth of the River Meander in Thales’s hometown of Miletus. These rivers would leave a layer of fertile soil which would begin the planting cycle all over again.

Water as the Principle Element of the Universe

Also, he noticed that water was ubiquitous. It fell from the sky, it was in the soil, and it was inside of plants. With observations such as these, it is no wonder that Thales concluded that water was the arche or principle element of the cosmos. As such, he believed that water then changed into earth, air, and fire (or Earth, Wind, & Fire, if you like).

There were two things that made Thales and the other Presocratics unique and distinguished them from those who came before. The first is that they looked for naturalistic explanations of things and the second is that they used rational arguments to come to their conclusions. Seeking knowledge about the cosmos made Thales a philosopher, and using rational arguments to come to his conclusions made him a scientist. In the beginning, philosophy and science were in essence the same. 

We have to be careful, though, in projecting our modern secular mindset onto the Presocratics. We could easily assume that by seeking naturalistic explanations, they denied the divine. Nothing could be further from the truth.

Christopher Hollis has a great quote in Noble Castle to this effect:

“The great Greeks did rightly use their reason to purify themselves of their superstitions, but reason did not lead them to the conclusion that rationalism was the explanation of all. It led rather to the conclusion that rationalism was insufficient.”13

In addition to the arche, the other thing that characterized the cosmos was movement. Movement for the Greeks meant life and being. So even though water was the naturalistic first principle of the universe according to Thales, the universe could not “be alive” or have movement unless it had a soul.14 Thales thought that a magnet was alive and therefore had a soul simply because it caused iron to move. Note the following quote from Aristotle:

“Thales, too, to judge from what is recorded of his views, seems to suppose that the soul is in a sense the cause of movement, since he says that a stone [magnet, or lodestone] has a soul because it causes movement to iron” (De An. 405 a20-22)15

For Thales, this soul permeated the universe. This prompted Aristotle to say, “For Thales, all things are full of gods.”16

Finally, I think that the following quote from Aristotle sums up Thales contribution to philosophy the best:

“Thales, the introducer of this sort of philosophy, said that it (the arche) was water (that is why he declared the earth to be sitting on water), perhaps drawing this supposition from seeing that the nourishment of all creatures is moist and that warmth itself that arises from this and that it is by this that all creatures live (and the assumption that that from which a thing comes is its principle in all cases). For this reason, indeed, taking this assumption and also because the seeds of all creatures have a moist nature and water is the natural principle for moist things.17


Unfortunately, what writings we have of Thales exist only in fragments and quotes from later philosophers. We don’t know the full extent of his beliefs. I find it interesting that he may have posited an early form of dualism where the universe had a physical origin but was animated by a divine soul. Later philosophers such as Thomas Aquinas would further develop these ideas of causation. Aquinas talked about primary and secondary causation. Primary causation is the being of everything which has its origin in the divine, and secondary causation involves the creatures who are dependent on the divine. 

The important thing is that Thales and the Presocratics became the first thinkers to look for a naturalistic explanation of the universe and to use rational arguments to do so. Thales rejected the mythological Greek pantheon of gods as an explanation for natural phenomena. By doing this, he laid the foundation for other Presocratic philosophers as well as for the development of science. Like Thales, these subsequent thinkers would look for the primary element of matter, but unlike Thales, they would choose something different from water. 

One account of Thales’s death said that he died from dehydration after watching a sporting event in the hot sun for several hours without drinking water. If this is true, how ironic that the man who said everything was made of water died from dehydration! I leave you the a quote about Thales from the the later Greek writer Diogenes Laertius (3rd century AD):

“This wise Thales died while present as a spectator at a gymnastic contest, being worn out with heat and thirst and weakness, for he was very old, and the following inscription was placed on his tomb. You see this tomb is small—but recollect, the fame of Thales reaches to the skies.”18


“God is the most ancient of all things, for he had no birth.”


“The most difficult thing in life is to know yourself.”


What do you find most interesting about Thales’ life. Please leave a comment below. Thank you!



  1. O’Grady, Patricia, “Thales of Miletus (c. 620 B.C.E.—c. 546 B.C.E.,” introduction, Internet Encyclopedia of Philosophy, https://iep.utm.edu/thales/#SH8c; The well story in found in an excerpt from Plato’s Theaetetus, 174a found at http://www.perseus.tufts.edu/hopper/text?doc=plat.+theaet.+174a
  2. O’Grady, Patricia, “Thales of Miletus”
  3. Kerferd, George Briscoe. “Sophist”. Encyclopedia Britannica, 6 May. 2020, https://www.britannica.com/topic/Sophist-philosophy
  4. Mosshammer, Alden A. “Thales’ Eclipse.” Transactions of the American Philological Association (1974-), vol. 111, 1981, pp. 145–155. JSTOR, www.jstor.org/stable/284125
  5. O’Grady, Patricia, “Thales of Miletus”
  6. Britannica, The Editors of Encyclopedia. “Miletus”. Encyclopedia Britannica, 12 Nov. 2019 https://www.britannica.com/place/Miletus
  7. Aristotle, Politics, book 1, section 1259a
  8. O’Grady, Patricia, “Thales of Miletus (c. 620 B.C.E.—c. 546 B.C.E.,” introduction, Internet Encyclopedia of Philosophy
  9. Aristotle, The Metaphysics, pp. 12-3, translated by Hugh Lawson-Tancred, Penguin Books, London, 1998, reprint 2004
  10. Furley, David J. “The Greek Theory of the Infinite Universe.” Journal of the History of Ideas, vol. 42, no. 4, 1981, pp. 571–585. www.jstor.org/stabl
  11. Longrigg, James. “The ‘Roots of All Things.’” Isis, vol. 67, no. 3, 1976, pp. 420–438. JSTOR, www.jstor.org/stable/230682
  12. Bouwman, Will, “Philosophy’s Roots and Branches,” Philosophy Now, https://philosophynow.org/issues/104/Philosophys_Roots_and_Branches
  13. Hollis, Christopher, The Noble Castle, p. 13, Longmans, Green and Co., London, New York, Toronto, 1941
  14. O’Grady, Patricia, “Thales of Miletus (c. 620 B.C.E.—c. 546 B.C.E.,” section entitled ‘All Things are Full of Gods.’
  15. Ibid.
  16. Aristotle, On the Soul, 411a 7-8, translated by Fred D. Miller, Jr., Oxford University Press, Oxford World Classics, Oxford, England, 2018
  17. Aristotle, The Metaphysics, (983b6], p. 13, translated by Hugh Lawson-Tancred, Penguin Books, London, 1998, reprint 2004
  18. Joshua, Mark, “Thales of Miletus,” New World Encyclopedia, September 2, 2009, https://www.worldhistory.org/Thales_of_Miletus

Bibliography and Sources:

Aristotle, On the Soul, translated by Fred D. Miller, Jr., Oxford University Press, Oxford World Classics, Oxford, England, 2018

Aristotle, The Metaphysics, translated by Hugh Lawson-Tancred, Penguin Books, London, 1998, reprint 2004

Aristotle, Politics, translated by R.F. Stanley and Ernest Barker, Oxford University Press, Oxford, England, 2009

Copleston, Frederick, A History of Philosophy, Book 1, Image Press, Cicero, N.Y., 1981

Dawson, Christopher, The Age of the Gods: A Study in the Origins of Culture in Prehistoric Europe and the Ancient East, Sheed and Ward, New York, 1950

Dawson, Christopher, The Dynamics of World History, public domain

Grayling, A.C., The History of Philosophy, Penguin Press, New York, 2019)

Hollis, Christopher, The Noble Castle, Longmans, Green and Co., London, New York, Toronto, 1941

Jones, E. Michael, Logos Rising, a History of Ultimate Reality, Fidelity Press, South Bend, Indiana, 2020

Voegelin, Eric, Order and History, Vol. 2: The World of the Polis, classic reprint, hardcover, Forgotten Books, London, 2018

Internet Sources:

Adamson, Peter, Lecture 1 “Everything is Full of Gods: Thales.” December 21, 2010, History of Philosophy Without Any Gaps, King’s College, London, https://historyofphilosophy.net/thales

Bouwman, Will, “Philosophy’s Roots and Branches,” Philosophy Now, https://philosophynow.org/issues/104/Philosophys_Roots_and_Branches

Check out this short video on Thales:

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