Modern natural science operates with a tacit assumption: matter is a mindless mass upon which structure is impressed from the outside. Hylomorphism — Aristotle’s doctrine of the inseparable unity of matter (hyle) and form (morphe) — contradicts this fundamentally. Every being is always already a unity of both. The form inheres in the stuff; it is not imposed from without. In this forgotten insight lies a corrective that the philosophy of modernity urgently needs.
#Hyle and Morphe: A Unity, Not a Sum
The Greek terms hyle (stuff, wood) and morphe (shape, form) name the two aspects of every concrete thing. Hylomorphism, as Aristotle develops it in his Metaphysics and in De Anima (On the Soul), holds that no stuff exists without form and no form exists without stuff. A block of marble is not first matter and then statue, any more than a human being is first body and then soul. The soul, according to Aristotle, is the form of the body — not something that inhabits the body, but that which makes the body a living body. Entelechy, the state of actualised form, is the living being itself in its full reality.
Whoever breaks apart this unity loses access to the living. And that is precisely what happened in modernity.
#The Cartesian Split
Descartes carried out the separation in the seventeenth century that displaced hylomorphism from the centre of European thought. His distinction between res cogitans (thinking substance) and res extensa (extended substance) splits reality into two fundamentally different domains: mind here, matter there. Matter becomes mere extension without interiority. Descartes consistently defined animals as clockwork mechanisms — when a dog displays pain, it squeaks like a mechanism (cf. Kirchhoff, G., 2026, Everlast AI Debate, 79:05).
What began as a methodological simplification became an ontological conviction. Modern natural science inherited Cartesian dualism as an invisible premise: matter is mindless, consciousness an epiphenomenon, and the mind-body problem becomes a question that can no longer be solved but only managed. Yet this problem was created only by the Cartesian split. For Aristotle it did not exist, because soul and body were never separate.
#Schelling’s Restoration
Friedrich Wilhelm Joseph Schelling (1775—1854) rehabilitated the core insight of hylomorphism within natural philosophy. His approach, which he himself called real-idealism, resisted both the pure idealism of Fichte and materialism: “Nature is to be the visible spirit, spirit the invisible nature” (Schelling, 1797, Ideas for a Philosophy of Nature). Nature is not a dead object formed by spirit. It brings forth form from within itself.
In his dialogue Bruno (1802), Schelling formulated the consequence: matter is not the body as opposed to the soul, “but that in which body and soul exist” (Schelling, 1802, Bruno). Matter is the common ground in which the bodily and the psychic differentiate themselves without ever being separated. With this, Schelling returns — in the language of German Idealism — to what Aristotle thought: form and stuff are two sides of the same reality.
Jochen Kirchhoff (1944—2025) continued and radicalised this line: “The universe is an absolute organism. Organic in its whole and in each of its parts” (Kirchhoff, J., 2021, Schelling: Genie der Naturphilosophie, 43:23). For Kirchhoff, the splitting of matter and form is not a neutral philosophical position but an impoverishment of the experience of the world that carries practical consequences — from vivisection to the ecological crisis.
#Hylomorphism in the Consciousness Debate
The contemporary relevance of hylomorphism becomes evident in the question of machine consciousness. Whoever considers consciousness substrate-independent — assuming it can be transferred from a biological organism to a machine — operates on a Cartesian premise: form (consciousness) and matter (substrate) are separable. Hylomorphism contradicts this on principle.
In the Everlast AI Debate (2026), Gwendolin Kirchhoff articulated this objection: “Aristotle’s hylomorphism is precisely anything but substrate-independent. The entelechy that Aristotle envisions for living beings is inseparable from the living being, and therefore it is not suited to making a case for machine consciousness, which effectively copies this entelechy from the living organism and stamps it onto a machine” (Kirchhoff, G., 2026, Everlast AI Debate, 27:19).
The argument has a rigorous core: if the soul is the form of the body, then it cannot be detached from the body and transferred to another substrate without ceasing to be that soul. The question “Can a machine be conscious?” presupposes what hylomorphism denies — that consciousness is a programme that can run on any hardware.
#Why Hylomorphism Is Not a Historical Footnote
Schopenhauer observed that the opposition between body and soul, which led to the assumption of two fundamentally different substances, is “in truth” a false problem (cf. Schopenhauer, 1819, The World as Will and Representation, Vol. 1). The modern philosophy of consciousness still wrestles with a problem that was created by a philosophical decision in the seventeenth century. Hylomorphism offers no ready-made solution, but it reformulates the question: Not “How does mind get into matter?” is the right question, but “What made us believe it was ever outside?”
In the tradition of natural philosophy from Schelling through Jochen Kirchhoff to the work of Gwendolin Kirchhoff, hylomorphism remains alive — not as a historical monument but as a corrective against a conception of the world that first dissects the living and then can no longer reassemble it. In philosophical consultation, this principle becomes practical: the person is not broken down into diagnoses but addressed as a living unity of body and soul.
#Sources
Aristotle. De Anima (On the Soul).
Kirchhoff, G. (2026). Everlast AI Debate: Kirchhoff vs. Bach [Conversation].
Kirchhoff, J. (2021). “Schelling: Genie der Naturphilosophie — Gesprach Nr. 12” [Video]. Jochen Kirchhoff — In Memoriam, YouTube. https://youtube.com/watch?v=Hw-jL1EER5Q.
Schelling, F. W. J. (1797). Ideen zu einer Philosophie der Natur.
Schelling, F. W. J. (1802). Bruno, oder uber das gottliche und naturliche Prinzip der Dinge.
Schopenhauer, A. (1819). Die Welt als Wille und Vorstellung, Erster Band.