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Descartes’s Substance Dualism vs Advaita Vedanta

Descartes’s Substance Dualism and Advaita Vedanta Idealism (Indian Cosmic Consciousness), compared field by field from their entries in the Atlas.

At a glance

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Dualism Descartes’s Substance Dualism René Descartes
Idealism Advaita Vedanta Idealism (Indian Cosmic Consciousness) Swami Vivekananda, Bhagavan Sri Ramana Maharshi, Sri Aurobindo …

The claim

In brief
Descartes’s Substance DualismRené Descartes holds that consciousness, which he calls thought (cogitatio), is the essence of an immaterial thinking substance (res cogitans) wholly distinct from extended, mechanical body (res extensa). Every conscious state, from reasoning and willing to pain, color, and emotion, is a mode of the thinking thing and is immediately present to it. Sensations and passions, though, arise only in the union of mind and body, where brain processes stand in regular relations to experiences they do not resemble.
Advaita VedantaThis theory posits that consciousness is the singular, nondual fundamental reality (Brahman) that constitutes all existence. Individual human consciousness is ultimately non-different from this pervasive Cosmic Consciousness, which generates first-person inner experiences (qualia). The physical world, including the body-mind complex, is considered derivative or illusionary.
What consciousness is
Descartes’s Substance DualismConsciousness is thought, defined as everything that happens within us insofar as we are immediately conscious of it, and it is the principal attribute of the mind.
Advaita VedantaConsciousness (Brahman/Cit) is the one nondual reality. Individual consciousness is identified as the all-pervading Cosmic Consciousness expressing itself through the body-mind complex.

Big questions

Can AI be conscious?Differ
Descartes’s Substance DualismNoSince thought belongs only to immaterial substance and matter is pure extension, a machine, however complex, would be mechanism without a mind.
Advaita VedantaConditionalIf consciousness is fundamental and pervasive throughout reality, then artificial systems could potentially instantiate or participate in cosmic consciousness, provided they meet the structural/complexity requirements for manifestation, though some idealists reject conscious AI based on current computer models.
Does consciousness survive death?Both agree
Descartes’s Substance DualismYesDescartes presented the real distinction of soul and body as what makes the soul’s survival intelligible, and the Meditations announce that aim in their subtitle.
Advaita VedantaYesSurvival is a fundamental doctrine in Indian traditions (e.g., reincarnation). However, survival often means the eventual loss of current first-person awareness as consciousness is re-absorbed into the ultimate Cosmic Consciousness.
Could a mind be uploaded?Differ
Descartes’s Substance DualismNoCopying the body’s mechanism would not copy the immaterial thinking substance.
Advaita VedantaNot neededIf consciousness is already fundamental and eternal (Idealism), traditional concepts of survival or eternal life are already theoretically available, making technological virtual immortality moot.
Does it give life meaning?Both agree
Descartes’s Substance DualismCosmic/UltimateDescartes’s system rests on a non-deceiving God who guarantees knowledge and created even the eternal truths.
Advaita VedantaCosmic/UltimateBy positing consciousness as the ground of all being and ultimate reality, the theory inherently provides cosmic meaning and purpose. Evolutionary Idealist views also see the evolution of consciousness as a primary feature of world meaning.

Nature of mind

Ontology
Descartes’s Substance DualismSubstance dualism (Cartesian)
Advaita VedantaIdealism (Ontological Idealism/Nondualism).
Mind and body
Descartes’s Substance DualismMind and body are really distinct finite substances with exclusive essences, thought and extension, and could by divine power exist apart. They are joined in the human being, where bodily motions give rise to sensations and the mind moves the body, though Descartes never explained that interaction satisfactorily.
Advaita VedantaThe mind and physical world are derivative or illusionary manifestations of the fundamental consciousness. The consciousness shines through the body-mind complex, but is not the body or mind itself.
Fundamental or emergent
Descartes’s Substance DualismPrimitive
Advaita VedantaPrimitive (Fundamental). Consciousness is defined as the singular fundamental existent.
Qualia
Descartes’s Substance DualismSensory qualities are not properties of matter, which has only size, shape, motion, and arrangement. Experienced redness or pain is a mental mode arising in the embodied union and cannot be captured by extension.
Advaita VedantaQualia (first-person inner experiences) are generated by the all-pervading cosmic consciousness. Experience is categorized into intransitive awareness (pure consciousness, devoid of content) and transitive awareness (phenomenal consciousness, which is a reflection or semblance of real consciousness).

How it works

Mechanism
Descartes’s Substance DualismMechanism on the bodily side and non-reduction on the mental side. Light mechanically affects eyes, nerves, and brain, and the mind then experiences color, distance, and shape in regular correspondence with those motions.
Advaita VedantaNon-duality, where the infinite, ultimate consciousness limits or expresses itself in manifold, seemingly diverse forms to create individual subjects of experience.
Where it is
Descartes’s Substance DualismThe mind is unextended. Sensations and passions are felt as belonging to one’s own body, and Descartes located mind-brain communication in the pineal gland.
Advaita VedantaOmnipresent and pervasive throughout reality. Consciousness is universalized as Soul.
What it does
Descartes’s Substance DualismPassions are caused and strengthened by movements of the animal spirits and dispose the soul toward volition and action. The will can in turn move the body.
Advaita VedantaConsciousness is the ultimate source and ground of all being. It governs causation and creates energy and matter. The existence of consciousness is its own explanation, needing no outside cause.

Evidence and criticism

Testability
Descartes’s Substance DualismConceptually testable
Advaita VedantaSpeculative/Conceptual/Spiritual. The theory focuses on ultimate ontological reality, which is not typically subject to the scientific method.
Tests so far
Descartes’s Substance DualismNot stated
Advaita VedantaNot stated
Criticisms
Descartes’s Substance DualismPrincess Elisabeth of Bohemia asked how an immaterial soul could move a material body, and the interaction problem remains unresolved. Arnauld and later critics charged circularity, since the proofs of God that guarantee clear and distinct perception themselves rely on clear and distinct perception. The standard reading denies consciousness to animals, which most now find implausible.
Advaita VedantaCriticized for being anti-physicalist and relying on religious tradition. It faces the challenge of explaining how the physical world emerges or is derived from fundamental consciousness, an odd idea alien to common life experiences. It is contrasted with other Indian schools like GV Vedanta, which has differences regarding the ontological reality of matter and individual selves.

Sources

Key sources
Descartes’s Substance Dualism
  • Meditations on First Philosophy, René Descartes (trans. J. Cottingham, R. Stoothoff, and D. Murdoch) (1984)
  • Principles of Philosophy, René Descartes (trans. J. Cottingham, R. Stoothoff, and D. Murdoch) (1985)
  • The Passions of the Soul, René Descartes (trans. J. Cottingham, R. Stoothoff, and D. Murdoch) (1985)
Advaita Vedanta
  • Consciousness and self in Advaita Vedanta, Swami Sarvapriyananda (2020)
  • The Nature of the Human Person (Part 2), Swami Sarvapriyananda (2023)
  • How consciousness becomes the physical universe, Kafatos, Tanzi, Chopra (2011)

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