Thales: 'All Things Are Water' — Where Philosophy Began

Conclusion First (Key Takeaways)

• From Myth to Reason: Thales rejected supernatural explanations and pioneered a mode of thought (logos) that explains natural phenomena through nature itself. "The birth of philosophy" is another name for this shift.
• The Invention of the "Question" of Archē: "All things are water" was surpassed within a generation. Even so, the way of posing the question — "There must be a fundamental principle (archē) common to all things" — has driven 2,600 years of inquiry.
• Uniting Theory and Practice: Thales reportedly predicted a solar eclipse through astronomical observation and cornered the olive-press market through commercial shrewdness. The first philosopher himself refuted the prejudice that "philosophers are useless."

Life and Historical Context

Thales was born around 624 BCE in Miletus, a port city in the Ionian region on the eastern coast of the Aegean Sea. At the time, Miletus was one of the foremost trading cities in the Mediterranean. Ships brought knowledge from Egypt, Babylonia, and Phoenicia; merchants used surveying and astronomical observation in their daily work. While the Greek mainland's city-states (poleis) were still taking shape, Ionia's commercial centers had already developed practical astronomy, surveying, and navigation.

Thales is said to have traveled to Egypt, where he learned geometry and surveying. The anecdote of his calculating the height of a pyramid from the length of its shadow is well known (Plutarch, Dinner of the Seven Sages 147a). He also absorbed Babylonian astronomical knowledge and reportedly predicted the solar eclipse of 585 BCE (Herodotus, Histories I.74). However, the precision of this prediction is debated among modern scholars. The Babylonians used the Saros cycle (approximately 18 years and 11 days) to predict lunar eclipses, but solar eclipses are visible only from limited areas, making it difficult to predict one for a specific location using the Saros cycle alone. It is therefore more likely that Thales announced a rough timeframe and that a fortunate coincidence elevated the story to legend (Kirk & Raven, 1983, pp. 76–79). Even so, his attitude of regarding natural phenomena as governed by regularity was bold for its time.

He was counted among the "Seven Sages" of Greece and was actively involved in politics. Herodotus records that Thales proposed the Ionian city-states form a federal government to counter the Persian threat (Histories I.170). Although the proposal was not adopted, it demonstrates considerable practical political judgment.

On the other hand, the famous story of his falling into a well while gazing at the stars (Plato, Theaetetus 174a) has been passed down as a joke about the absent-mindedness of philosophers. But Aristotle tells a contrasting tale. Using his astronomical observations, Thales predicted a bumper olive harvest, leased all the olive presses at a low price before the season began, and then rented them out at high prices during the harvest, earning a handsome profit (Politics 1259a). Through this anecdote, Thales demonstrated that "philosophers can make money if they wish — it simply is not what interests them."

Mini Timeline

• c. 624 BCE: Born in Miletus, Ionia (said to have been of Phoenician descent)
• c. 600 BCE: Travels to Egypt and studies geometry and surveying
• 585 BCE: Predicts a solar eclipse; connected to the ceasefire in the Lydian–Median War
• c. 580 BCE: Establishes his reputation as one of the "Seven Sages"
• c. 547/546 BCE: Dies in Miletus (around the time of Croesus's Lydian kingdom's fall)

What Did Thales Ask?

Before Thales, the workings of the natural world were explained exclusively through myth. According to Hesiod's Theogony, Chaos came first, then Gaia (Earth) and Eros (Love) emerged from it, and the universe was formed through a genealogy of gods. Weather changes were attributed to Zeus's anger, earthquakes to Poseidon's actions, and seasonal changes to Demeter's emotions.

Thales did not begin his thinking entirely from scratch. Near Eastern cosmogonies already contained the motif of "primordial water." In the Babylonian creation epic Enūma Eliš, the world arises from the primordial fresh water Apsû and the salt water Tiamat; in Egyptian mythology, too, all things emerge from the primordial water Nun. There is room to see Thales's "water" as influenced by these traditions. The decisive difference is that Thales presented this insight not as a story of gods, but as a principle of nature.

Thales's revolution was a transformation of the explanatory framework itself. "What, ultimately, is this world made of?" — To this question, he sought an answer not in the will of the gods but within nature itself. This represents the transition from mythos (mythological explanation) to logos (rational explanation) — not merely a change in the answer, but a transformation in the very structure of the question.

Aristotle later situated this transformation precisely. In Book I of the Metaphysics, he calls Thales "the founder of this kind of philosophy [the inquiry into nature]" and credits him as the first to inquire into the "material cause" of all things (983b20–22). The term "archē" (ἀρχή) that Aristotle uses here is a conceptual framework that he retroactively applied; whether Thales himself used this word is uncertain. Nevertheless, his position as the first thinker to systematically ask "What is the world made of?" is broadly accepted in modern philosophical historiography.

Core Theories

1. "All Things Are Water" — The First Monism

Thales's central thesis is that "the fundamental principle of all things is water (hydōr / ὕδωρ)." This is the first instance of what Aristotle would later call the "archē" (origin) — the fundamental principle from which all things arise and to which they ultimately return.

Why water? Thales's own explanation has not survived, but Aristotle speculates on several reasons (Metaphysics 983b22–27): that the seeds of all living things are moist in nature; that nourishment is derived from moisture; and the cosmological intuition that the earth floats on water. The geographic context — Miletus at the mouth of the Maeander River, surrounded by sea and river — also offers a clue.

Water is also the only common substance that assumes three states: liquid, solid, and gas. It evaporates and becomes invisible; it freezes and becomes hard as stone. The fact that a single substance could undergo such diverse transformations provided powerful empirical support for the hypothesis that "all things change from a single principle."

When modern physics states that "all matter is composed of combinations of elementary particles," the structure of its reasoning is identical to Thales's. The methodological stance of reductionism — explaining diverse phenomena through a small number of fundamental principles — was born in this port city 2,600 years ago.

However, Thales could not adequately answer the question "Why water and not fire or air?" His successor Anaximander (traditionally regarded as Thales's student) argued that because water is in opposition to fire just as specific elements oppose one another, the fundamental principle must be something not limited to any specific quality — the "Boundless" (to apeiron). Thales's answer was surpassed within a single generation, but his question — "There must be a common principle underlying all things" — was inherited directly by his successors.

2. From Mythos to Logos — A Structural Shift in Explanation

Thales's true achievement lies not in the answer "water" but in the revolution of how one asks questions. Ancient Greek mythology narrated natural phenomena as the acts of personified gods — lightning was Zeus's weapon, seasonal change was attributed to Demeter's emotions. In this framework, the question was not "Why does this happen?" but "Who did this?" Thales was the first to replace "Who?" with "What?"

Following Popper, we can put it thus. Mythological explanations are in principle unfalsifiable. The explanation that Zeus hurls lightning is confirmed every time thunder strikes, yet never refuted when it does not. Thales's "water" hypothesis, by contrast, is open to criticism — and indeed, Anaximander promptly criticized it. Philosophy and science can "progress" precisely because hypotheses remain open to refutation.

Many of the "conspiracy theories" circulating on social media today share the mythos-like structure of attributing everything to a specific intention or hidden mastermind. Thalesian thinking is the stance of asking: "Is this really supported by evidence?"

Thales also stated that "all things are full of gods" (πάντα πλήρη θεῶν; Aristotle, De Anima 411a7). His was not a complete "demythologization." The birth of philosophy was a gradual transition rather than a dramatic rupture.

3. Hylozoism — "Living" Matter

Thales observed that a magnet (the "Magnesian stone") attracts iron and that amber (elektron) attracts straw when rubbed, and he inferred that "soul (psychē) is mingled with matter" (Aristotle, De Anima 405a19–21). In the terminology of modern philosophical history, this view is called hylozoism.

For Thales, the universe was not an aggregate of inert matter but a living whole that moves and changes of its own accord. Water evaporates, solidifies, and flows because the power of change is inherent in water itself. This idea — seeking the cause of motion within matter rather than in an external supernatural force — also lies along the extension of logos-based thinking.

To modern eyes, hylozoism looks like anthropomorphism. Modern science, since Descartes, has treated nature as a precise machine and leapt forward. In the 21st century, things have shifted again. James Lovelock's Gaia hypothesis views the entire Earth as a single self-regulating system; "emergence" in complexity science — where unexpected order arises from simple elements — blurs the boundary between matter and life. Thales's hylozoism does not hold as rigorous physics, but his intuition that "the world is not a heap of dead matter" is hard to dismiss entirely.

4. Geometry and Astronomy — Demonstrating Theoretical Knowledge

Thales is credited as the first to bring Egyptian surveying techniques to Greece and recast them as deductive geometry. "Thales's theorem" (that an angle inscribed in a semicircle is a right angle) is the best-known example. However, many of the mathematical achievements attributed to Thales come from later traditions (e.g., Proclus's Commentary on Euclid, dating to the 5th century CE), and it remains uncertain how much can be ascribed to Thales personally.

The crucial point is the transformation in the character of knowledge. Egyptian geometry was a practical technique for resurveying land after the Nile floods. Thales is said to have converted it into a theoretical discipline that asks "Why does this hold?" His method of calculating the height of a pyramid from the length of its shadow was based on the principle of similar ratios — an early example of applying abstract mathematical relationships to concrete problems.

"Modeling" in data science — capturing the complexity of real-world phenomena through mathematical structures — shares the same intellectual root as Thales's abstraction of surveying into geometry.

Key Works Guide

No writings by Thales himself survive. Diogenes Laërtius mentions the existence of a work called Nautical Star-Gazing (Nautikē Astrologia), but it too has been lost. Thales's thought can only be reconstructed through later testimonies. The following readings deepen that understanding.

• Introductory: Diogenes Laërtius, Lives of the Eminent Philosophers, Book I — The most comprehensive source for Thales's life, anecdotes, and aphorisms. An entry point for grasping the man.
• Intermediate: Aristotle, Metaphysics, Book I — Aristotle's own analysis of Thales's archē theory and its position in the history of philosophy. Section 983b is the core. Read with an eye to Aristotle's interpretive bias.
• Intermediate: Herodotus, Histories, Book I — The historical record closest in time to Thales, including the eclipse prediction (I.74) and the proposal for an Ionian union (I.170).
• Advanced: G. S. Kirk, J. E. Raven, M. Schofield, The Presocratic Philosophers, 2nd ed., Cambridge UP, 1983 — A critical examination of the fragments and testimonies, rigorously reconstructing Thales's thought. The standard reference for early Greek philosophy.

Major Criticisms and Debates

1. Anaximander's Critique (Contemporary): Anaximander, traditionally regarded as Thales's student, was quick to point out the limitations of positing "water" — a specific element — as the archē. Water is merely one of the elements that stand in opposition to one another (fire, air, earth), and therefore the fundamental principle must be something not limited to any particular quality — the "Boundless" (to apeiron / τὸ ἄπειρον). This can be seen as the first "constructive criticism" in the history of philosophy: rejecting the answer while inheriting and refining the question.

2. Aristotle's Evaluation and Reservations (Later): Aristotle praised Thales highly as a seeker of the "material cause" while noting the absence of the formal, efficient, and final causes. "What it is made of" alone is insufficient as an explanation for "why it is so" — a systematic critique grounded in his four-cause framework. Aristotle reinterprets Thales as a "precursor" within his own philosophical system. That bias cannot be bypassed when reading Thales.

3. The "Was Thales Really a Philosopher?" Debate (Modern): Some 20th-century scholars (e.g., M. L. West) questioned the extent to which Thales's thought was original versus borrowed from the Near East. The parallels with Enūma Eliš and Nun are undeniable. Yet many historians of philosophy (Kirk, Furley, Graham, among others) locate Thales's originality not in the origin of his material but in the novelty of his "attitude of pursuing rational explanation." Beyond "what he said," it is "how he said it" — presenting his ideas not as mythological narrative but as natural principle — that marks the beginning of philosophy.

Influence and Legacy

Antecedent Thought: Babylonian astronomy (astronomical predictions using the Saros cycle), Egyptian surveying (practical geometry), Near Eastern water cosmologies (the primordial waters Apsû and Tiamat in the Babylonian Enūma Eliš; Nun in Egyptian mythology), Hesiod's Theogony (the mythological precursor to cosmogony).

Direct Successors (The Milesian School): Thales's question — "What is the fundamental principle of all things?" — became the shared intellectual property of the entire Milesian school. Anaximander posited "the Boundless" (to apeiron), and Anaximenes posited "air" (aēr) as the archē. All three offered different answers while sharing the same structure of inquiry. This pattern — "different answers, shared question" — is at the very heart of the philosophical tradition.

Distant Successors: Through Empedocles's four-element theory and Democritus's atomism, Thales's quest for the archē eventually bore fruit in the modern chemical concept of elements and the periodic table. Mendeleev's periodic table can be seen as one answer — 2,400 years after Thales — to the question "What is everything made of?" The Standard Model pursued by contemporary particle physics also stands in this lineage.

Beyond Philosophy: The intellectual desire to "explain complex things through a single principle" began with Thales and extends not only to science but to economics (marginal utility theory, which reduces everything to utility), data science (converting everything to numbers and capturing correlations).

Connection to the Present

Thales's legacy lies not in the specific answer "water" but in the conviction that "the world should be explicable by a single principle." This conviction continues to drive science and technology 2,600 years later.

When physicists pursue a "Theory of Everything," it is the cutting-edge form of Thales's quest for the archē. When scientists seek a unified description of fundamental forces, behind it lies the Thalesian belief that "there is a structure common to diverse phenomena."

Reductionism is powerful, but the belief that "everything can be reduced to a single principle" overlooks what cannot be reduced — consciousness, meaning, beauty, the unrepeatable singularity of an individual life. The contemporary reductionism of "everything is data" — what exactly does it leave behind? The right to pose that question is also one Thales opened.

Questions for the Reader

• If you were to claim that "there is one ultimate principle of the world," what would it be? Energy, information, consciousness, or something else? And does your answer carry the same weakness as Thales's?
• Where does the transition from "mythos to logos" lie in the modern world? What "modern myth" have you accepted uncritically?
• Thales responded to the criticism that "philosophers are useless" by cornering the olive-press market. When the humanities face the same criticism today, how would you respond?

References

• Primary Source (Testimonies and Fragments): H. Diels & W. Kranz, eds., Die Fragmente der Vorsokratiker, Vol. 1, chapter on Thales (DK 11)
• Primary Source (Testimonies): Aristotle, Metaphysics, Book I; Aristotle, De Anima
• Primary Source (History): Herodotus, Histories, Book I — Eclipse prediction (I.74), Ionian Union proposal (I.170)
• Primary Source (Biography): Diogenes Laërtius, Lives of the Eminent Philosophers, Book I
• Secondary Source (Standard Reference): G. S. Kirk, J. E. Raven, M. Schofield, The Presocratic Philosophers, 2nd ed., Cambridge UP, 1983
• Secondary Source (Survey): Patricia Curd & Daniel W. Graham, eds., The Oxford Handbook of Presocratic Philosophy, Oxford UP, 2008
• Secondary Source (Near Eastern Comparison): M. L. West, Early Greek Philosophy and the Orient, Oxford UP, 1971 — A classic study examining influence from Near Eastern cosmologies