Unity in Milesian Metaphysics and Its Contrast with Non-Duality in Advaita Vedanta

George Greensmith
April 2026

The Milesian philosophy of the archê and the non-conceptual metaphysics described in Advaita Vedanta, aim to answer the question of being. Exploration of a non-divided reality is a common feature of both schools of thought. This essay discusses whether the Milesian school's concept of the archê is similar to the absolute reality (Brahman) in Advaita Vedanta.

The Milesian Philosophers

The Milesian philosophers aim to explain metaphysics through monism, reducing all things to a primary substance (the archê). Thales believed the archê to be water because of its essentiality for human life. Anaximander claimed the archê was an immaterial and formless substance called apeiron. Anaximenes, a student of Anaximander, believed air was the archê because of its transformative properties such as rarefaction or condensation.

Thales was the first Milesian philosopher who logically addressed metaphysical questions such as "what is the world made out of?". He was the first to explain reality as comprised of a single material substance, and conceptualized a primary element (the archê) as the source of all. Thales avoided attributing metaphysics to divine intervention and instead used rational inquiry. Although Acheloios, a water deity with transforming attributes commonly worshiped in Miletus, may have influenced Thales to believe "Gods are in all things".ⁱ His theory of water, as described in Aristotle's metaphysics, posits the ocean as the foundation of the cosmos.ⁱⁱ According to this theory, the Earth was a flat disk spawned of the ocean and rested upon its surface. This offered a material cause (water) to explain metaphysics, rather than a supernatural one. Thales' interest in metaphysics and the archê was later explored deeply by his successor Anaximander.

Anaximander thought the archê was immaterial. He was the first to use the term archê in a philosophical context and explain metaphysics through conceptual abstraction. Anaximander thought the archê was apeiron – a Greek word for infinite or indefinite – and believed in the laws of nature.ⁱⁱⁱ Apeiron is an abstract concept and eternal substance. He argued water does not embrace opposites, it is only wet and never dry, therefore Anaximander said it cannot be the archê. However, Anaximander incorrectly believed that mankind originated from embryos in the mouths of fish and incorrectly ordered the solar system.^iv

Thales and Anaximander rationally explained the origins of phenomena, yet they disagree on the archê and solar system cosmology. Anaximander described the earth as a cylinder structure that floats in the infinite. He rejected Thales's flat earth theory and argued earth was in the center of the cosmos, not reliant on physical support. Thales theorized about the transformative properties of water and its essentiality for human life. The appeal to transformative properties and essentiality was also made by Anaximenes for air and Heraclitus for fire.^v However, these features do not justify an element as the archê. Empirical features are insufficient to ground metaphysics because they are contingent on observation. They do not prove metaphysics must be that way. Thales explains "how" reality is, but not what brings it into existence or why it exists. We cannot understand why reality exists from observing the natural world. Also, Milesian monism is also too simplistic to account for change and complexity. There is a lack of explanation for how elements become their opposites. For example, how does water become fire? There is no explanation of how the archê changes into other things. Ultimately, the Milesians reliance on observation harms their empirical validity.

Advaita Vedanta

Advaita Vedanta is a non-dualistic school of Hindu philosophy, that views the absolute (Brahman), the transcendental self (Atman) and experiencing self (Jiva) as one entity.^viAdvaita means non-secondness, or more precisely "that which has no second beside it".^vii It is often translated as "non-duality" to mean the denial or transcendence of dualism. Non-dualism is the philosophy which discusses non-dual awareness, a condition that arises prior to thought. Vedanta means the "culmination of knowledge", or more literally the end of the Vedic texts. Advaita Vedantins argue that ultimate reality is non-conceptual. In their view, awareness prior to thought is the grounds of reality.

Brahman, according to the Rigveda and Upanishads, is a forever unchanging entity that created the universe. It is the grounds of the universe on which all things depend, free from space, time and causation. Brahman is said to be both in all things and transcendent of them, and therefore irreducible to form or substance. Brahman is not the God of Abraham, rather it is the term for a formless, limitless reality, often interpreted as pure consciousness that is all things.^viii No matter how far we deconstruct forms, all that remains is existence (Brahman) with different shapes and names. For example, clay can be used to make clay pots, but the forms of clay pots are dependent on the existence of clay itself.^ix Just as we can remove the name "pot" from the form to understand all is clay. Realising the self (Atman) is Brahman allows us to understand our true existence. Although this existence is non-dual and without form, therefore cannot be reduced to one substance.

The Archê and Brahman

In the 6th century BCE there was no distinction between material and spiritual. This led the Milesians to conceive the archê as a non-conscious but self moving energy.^x The archê (apeiron) is a non-spiritual explanation of a substance-based metaphysics. Apeiron is described as a non-conscious, formless and eternal source of matter. By contrast, Brahman is described as a conscious, formless and eternal supreme consciousness. Brahman is not a formless "stuff" like apeiron, it is the grounds where "stuff" occurs. Framed as a metaphor, Brahman is the screen on which the movie of reality is played, and the archê is the motion of light that forms the picture.

The commonality between the Milesian philosophers and Advaita Vedanta is their metaphysical non-dualism, as they claim either a single substance or Brahman to be the grounds of reality. If the Milesians are trying to answer "What is existence made of?", Advaita Vedanta is asking "What is the fundamental essence of existence?". The fundamental disagreement is on the semantic axis of "one thing" versus "not-two". The former implies there is a substance we can call the source of reality. While the latter implies there is no such other "thing" apart from Brahman. The Milesian philosophers attribute "stuff" to the underlying essence of what absolute reality is. This is not compatible with Advaita Vedanta because the essence of reality is formless, and not reducible to substance alone. Neither does the archê offer spiritual insight or an ultimate explanation of the grounds of existence. If Milesians were concerned with identifying the primary substance of reality, Advaita Vedanta avoids the discussion of substances altogether and instead focuses on the condition that makes any substance possible. This is what they call Brahman. Pushed to its philosophical extreme Brahman is everything, including what is beyond concept.

Endnotes

i Nicholas J. Molinari, "Acheloios, Thales, and the Origin of Philosophy: A Response to the Neo-Marxians." ↩
ii Aristotle, Metaphysics, trans. W. D. Ross, 983b. ↩
iii David Park, The Grand Contraption: The World as Myth, Number, and Chance (Princeton: Princeton University Press, 2005). ↩
iv Censorinus, De Die Natali, IV.7. ↩
v Bertrand Russell, A History of Western Philosophy (London: Routledge, 1946), chap. 4. ↩
vi "Advaita Vedanta," Internet Encyclopedia of Philosophy, https://iep.utm.edu/advaita-vedanta/ ↩
vii "Dvaita," Encyclopedia Britannica, February 19, 2015. ↩
viii "Brahman," Encyclopaedia Britannica, https://www.britannica.com/topic/brahman-Hindu-concept ↩
ix N. Dalal, "Śaṅkara," Stanford Encyclopedia of Philosophy, 2021. ↩
x "The Milesian Philosophers," Kinnu, https://kinnu.xyz/kinnuverse/philosophy/the-timeless-wisdom-of-great-greek-philosophers/milesians/. ↩

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