Aristotle’s Hylomorphism

Aristotle nowhere uses a single word for consciousness and never asks why experience should feel like anything, yet De Anima and its companion treatises contain the first systematic account of what it is for a living body to be aware: the soul is the form of an organic body rather than an occupant of it, perception is the reception of sensible form without matter, and perceiving carries within itself an awareness that one is perceiving. What contemporary readers identify as phenomenal consciousness in Aristotle is located almost entirely in this reflexive structure and in the unifying work of the common sense, and scholarship divides sharply over whether that structure amounts to a theory of phenomenal consciousness or to a theory of perceptual capacity that leaves phenomenality untouched. The dispute is not antiquarian. Transmitted through Aquinas and the scholastics to Brentano, Aristotle's reflexivity thesis supplied phenomenology with its founding concepts, and it is now actively defended by same-order theories of self-awareness and by neo-Aristotelian hylomorphists who argue that the hard problem arises only because hylomorphism was abandoned.

In other words, while Aristotle has no single concept corresponding exactly to the modern notion of phenomenal consciousness, his psychology contains a systematic account of the capacities from which conscious experience can be reconstructed: perception is the embodied activity of an ensouled animal receiving sensible form without matter; a unified perceptual power integrates modalities and, in some sense, perceives that it perceives; pleasure, pain, desire, imagination, memory, and thought elaborate the animal’s lived world. His hylomorphism rejects both reductive materialism and a Platonic picture of an independently existing soul, although his obscure treatment of intellect leaves open a partially nonbodily dimension (Aristotle, 1984a; Shields, 2022). This framework shaped Aquinas and remains relevant to contemporary hylomorphism, embodied cognition, functionalism, direct-realist and representational approaches, and higher-order and self-representational theories of consciousness.

Reconstructing Phenomenal Consciousness

The reconstruction requires an anachronism warning. Aristotle never asks the post-Cartesian question why physical processing should generate subjective experience. Yet he distinguishes waking perception from sleep, sensation from mere physical affection, appearance from thought, and activities of which an animal is in some way aware from those occurring without awareness. Most importantly, De Anima III.2 asks how we perceive that we see and hear, while Nicomachean Ethics IX.9 argues that when we perceive, we perceive that we perceive, and when we think, we apprehend that we think (Aristotle, 1984a, 1984c; Caston, 2002). These passages make phenomenal awareness a legitimate target of reconstruction, provided Aristotle’s vocabulary is not silently replaced by ours.

The Hylomorphic Subject of Experience

For Aristotle, psyche—soul—is not normally an immaterial occupant of a body. It is the “form” and first actuality of a natural organized body capable of life: the principle that makes this living material one functioning organism (De Anima II.1). Perceptual consciousness therefore belongs to the living animal as an integrated compound, not to a Cartesian mind observing bodily inputs from within (Aristotle, 1984a; Shields, 2022).

This makes Aristotle neither straightforwardly materialist nor straightforwardly dualist. He rejects attempts to explain life entirely from material elements, but also resists Plato’s general separability of soul from body. Most psychic powers are actualities of bodily organs. The complication is nous, intellect: Aristotle says that intellect lacks a bodily organ and describes the active intellect in terms that have generated two millennia of disagreement about separability and immortality (De Anima III.4–5). Thus embodied sentience is firmly hylomorphic; whether intellect introduces genuine ontological duality remains unsettled.

The Hylomorphic Frame

Aristotle's psychology is not a freestanding science of mind but a regional application of a comprehensive metaphysics of form and matter, actuality and potentiality; what the psychological doctrines mean depends on that frame. The soul is "substance as form of a natural body which has life in potentiality" (De Anima II.1, 412a20–21) and "a first actuality of a natural body which has life in potentiality" (412a27–28), which is why asking whether soul and body are one is as idle as asking whether the wax and its shape are one. The soul as a whole is not separable from the body (413a3–5). Accordingly, there is no Cartesian problem to solve, because no thinking substance's interaction with an extended substance requires explanation; Charles (2021) argues that Aristotle's position dissolves rather than answers the mind–body problem as later philosophy inherited it. The soul is a nested hierarchy of capacities—nutritive, perceptual, rational—so that being alive, being sentient, and being rational are graded actualities of a single organism rather than additions to it (Shields, 2016).

Sensation as Receiving Form Without Matter

The perceptual capacity is "receptive of the sensible forms without the matter" (De Anima II.12, 424a17–21), a formula that has become the crux of the modern debate over how much phenomenal content Aristotle's theory can carry. Sorabji (1992) reads the reception as a genuine physiological alteration: the sense organ literally takes on the quality, so that the eye-jelly becomes colored and this material change constitutes seeing. Burnyeat (1992) denies that any material change accompanies perception, treating awareness as primitive and unexplained, and concludes that an Aristotelian philosophy of mind is not credible in a post-Newtonian world. Nussbaum and Putnam (1992) defend a middle position on which the psychological is realized in, without being reducible to, the material, and Cohen (1992) presses the question of how far this really licenses calling Aristotle a functionalist. Everson (1997) develops the physiological reading in detail. The stakes are direct: on the physiological reading Aristotle offers something like a mechanism for sensory quality, while on Burnyeat's reading he takes the felt character of awareness as a starting point requiring no account.

Perceiving That We Perceive

The passage that carries the weight of the consciousness question is De Anima III.2, 425b12–25, where Aristotle asks by what we perceive that we are seeing. If by sight, sight would have to perceive its own object and also itself; if by some further sense, a regress looms. His answer is that it is in a way by sight itself. The same claim recurs in ethical guise: if we perceive, we perceive that we perceive, and to perceive that one perceives is to perceive that one exists, which is pleasant (Nicomachean Ethics IX.9, 1170a29–b1). Kosman (1975) argued influentially that this awareness is not a distinct second-order act but an aspect internal to the first-order act of perceiving. Caston (2002) sharpened the reading into a position that cuts between contemporary alternatives: consciousness is simultaneously intrinsic and higher-order, because a single token state has both a first-order and a reflexive content. On the same reading, Caston holds that Aristotle is committed against qualia in any strong sense, while denying that the phenomenal character of experience is exhausted by what is represented. Johansen (2012) defends instead a genuine inner-sense construal, and Trubowitz (2025) has disputed the Kosman–Caston lineage at its textual root. The exegetical question is unsettled, and with it the question of what precisely Aristotle thought phenomenal awareness consists in.

Unity, Phantasia, and the Common Sense

Reflexive awareness is bound up with the koinē aisthēsis, the common perceptual capacity by which an animal discriminates across sense modalities, perceives the common sensibles such as motion and magnitude, and registers that it is perceiving at all (Gregoric, 2007). This yields something a modern theorist would recognize as a unity claim: an episode of experience is one integrated presentation, not a bundle of modality-specific channels. Phantasia (De Anima III.3) extends the account to appearances that persist when their objects are absent, giving Aristotle a category for imagery, dreaming, and memory—experiential content decoupled from present stimulation. Together these supply an architecture of experience: unified, reflexive, embodied, and graded across the animal kingdom.

Nous and the Systemic Terminus

Aristotle's naturalism about psuchē does not extend to intellect. In De Anima III.5 he describes the active mind as "separate and unaffected and unmixed, being in its essence actuality" (430a17–18) and as "deathless and everlasting" (430a23), in evident tension with his earlier denial that soul is separable from body. The systemic frame supplies the norm behind this: in Metaphysics XII.9 (1074b33–35) the divine substance is thought thinking itself, perfect and complete reflexivity, and human intellectual self-awareness is intelligible as a deficient participation in that standard. Whether the active intellect is a part of the individual, a single intellect shared by all, or the divine mind itself became the central controversy of the Greek, Arabic, and Latin commentators, and it is the seam through which nonphysicalist readings of Aristotle enter.

Aquinas and the Scholastic Inheritance

Aquinas preserved the hylomorphic unity—the soul is the substantial form of the body—while arguing that the intellectual soul is subsistent and survives the body's death (Summa Theologiae Ia, q. 75, aa. 2, 6), a conclusion Aristotle's text does not obviously prefigure. He assigned the awareness that we sense, and the integration of the external senses, to the sensus communis (Ia, q. 78, a. 4), and held that the mind knows itself only through its acts rather than by direct inspection (Ia, q. 87, a. 1). This is the transmission route by which the Aristotelian architecture entered Christian philosophy, and it is developed on the Landscape by Aquinas's Hylomorphism, Stump's Thomistic Dualism, and Feser's Neo-Thomistic, Neo-Aristotelian, Common-Sense Dualism.

Brentano to Contemporary Theory

The clear modern conduit is Franz Brentano, whose habilitation was devoted to Aristotle's active intellect (Brentano, 1867) and who reintroduced the scholastic-Aristotelian intentio as "intentional inexistence," the mark of the mental (Brentano, 1874). Brentano's further thesis that every mental act includes a secondary awareness of itself is the Aristotelian reflexivity claim in modern dress, and Sorabji (1991) traces the concept's development along precisely this line. Through Brentano the structure passed to Husserl and to phenomenology, and it lives on the Landscape in Brentano's Intentionality and Self-Awareness, Meinong's Self-Presenting Experience, and Husserl's Transcendental Phenomenology.

In analytic philosophy of mind, the same structure reappears in self-representational accounts, where conscious states are represented by themselves rather than by distinct higher-order states, and Caston's Aristotle is routinely cited as the ancestor (Kriegel, 2009), a lineage visible on the Landscape in Kriegel's Cross-Order Self-Representation. The metaphysical frame has had a parallel revival: Jaworski (2016) contends that the hard problem arises only on the assumption that hylomorphism is false, Marmodoro (2013) argues that Aristotle's own version needs no contemporary repair, and Koslicki (2018) develops structure-based hylomorphism in mainstream metaphysics. Jaworski's Hylomorphism sits on the Landscape as the contemporary terminus of this line.

Explanatory Power and Limits

Aristotle does not even recognize, much less attempt to solve, the modern hard problem because he never isolates phenomenal properties as anomalous facts requiring derivation from nonphenomenal physical facts. He starts from a different ontology in which living capacities, bodily organization, sensible qualities, affect, action, and cognition are explained together through form, matter, actuality, and teleology. Its strengths are the unity of subject and organism, embodied and world-involving perception, integration of affect and action, and recognition of reflexive awareness. Its limitations are equally clear: Aristotle’s physiology is obsolete, “reception of form” remains opaque, the status of intellect is unresolved, and nothing in the theory demonstratively explains why perceptual actualization should have a subjective “what-it-is-like” character. Aristotle supplies one of the deepest premodern architectures for phenomenal consciousness—but, reconstructed with historical discipline, an architecture rather than a completed modern theory.

Assessment

What Aristotle supplies is a structural account of awareness—reflexive, unified, embodied, graded—rather than an explanation of why experience has felt quality. The two dominant readings converge on this point from opposite directions: Caston's Aristotle denies strong qualia, and Burnyeat's Aristotle treats awareness as primitive and therefore unexplained. Neither Aristotle poses the hard problem. Whether that silence reflects an obsolete physics or diagnoses a badly framed question is what separates contemporary neo-Aristotelians from their critics, and it is why an author writing before the concept of consciousness existed remains a live participant in the field that concept catalyzed.

A note on classification. Aristotle sits in this Dualisms category as the source of the hylomorphic lineage running through Aquinas, Stump, Feser, and Jaworski; on the standard reading, Aristotle’s own position is not a substance dualism, since the soul is the form of the body and not separable from it, and only the active intellect of De Anima III.5, "deathless and everlasting," argues against that.

References

[Convention note: Aristotle is cited by standard Bekker page, column, and line. Line numbering follows Shields (2016) for De Anima and the Revised Oxford Translation (Barnes, 1984) for the Nicomachean Ethics and Metaphysics. Summa Theologiae is cited by part, question, and article.]

Aquinas, T. (1265–1274/1948). Summa Theologiae. Trans. Fathers of the English Dominican Province. Westminster, MD: Christian Classics.

Barnes, J. (ed.) (1984). The Complete Works of Aristotle: The Revised Oxford Translation. Princeton: Princeton University Press.

Brentano, F. (1867). Die Psychologie des Aristoteles, insbesondere seine Lehre vom ΝΟΥΣ ΠΟΙΗΤΙΚΟΣ. Mainz: Kirchheim. [Eng. trans. R. George, The Psychology of Aristotle: In Particular His Doctrine of the Active Intellect. Berkeley: University of California Press, 1977.]

Brentano, F. (1874). Psychologie vom empirischen Standpunkte. Leipzig: Duncker & Humblot.

Burnyeat, M. F. (1992). "Is an Aristotelian Philosophy of Mind Still Credible? (A Draft)." In M. C. Nussbaum and A. O. Rorty (eds.), Essays on Aristotle's De Anima. Oxford: Clarendon Press, 15–26.

Caston, V. (2002). "Aristotle on Consciousness." Mind 111(444): 751–815.

Charles, D. (2021). The Undivided Self: Aristotle and the 'Mind–Body' Problem. Oxford: Oxford University Press.

Cohen, S. M. (1992). "Hylomorphism and Functionalism." In M. C. Nussbaum and A. O. Rorty (eds.), Essays on Aristotle's De Anima. Oxford: Clarendon Press, 57–73.

Everson, S. (1997). Aristotle on Perception. Oxford: Clarendon Press.

Gregoric, P. (2007). Aristotle on the Common Sense. Oxford: Oxford University Press.

Jaworski, W. (2016). Structure and the Metaphysics of Mind: How Hylomorphism Solves the Mind–Body Problem. Oxford: Oxford University Press.

Johansen, T. K. (2012). The Powers of Aristotle's Soul. Oxford: Oxford University Press.

Koslicki, K. (2018). Form, Matter, Substance. Oxford: Oxford University Press.

Kosman, L. A. (1975). "Perceiving That We Perceive: On the Soul III, 2." The Philosophical Review 84(4): 499–519.

Kriegel, U. (2009). Subjective Consciousness: A Self-Representational Theory. Oxford: Oxford University Press.

Marmodoro, A. (2013). "Aristotle's Hylomorphism Without Reconditioning." Philosophical Inquiry 37(1–2): 5–22.

Nussbaum, M. C., and Putnam, H. (1992). "Changing Aristotle's Mind." In M. C. Nussbaum and A. O. Rorty (eds.), Essays on Aristotle's De Anima. Oxford: Clarendon Press, 27–56.

Shields, C. (2016). Aristotle: De Anima. Translated with an Introduction and Commentary. Oxford: Clarendon Press.

Sorabji, R. (1991). "From Aristotle to Brentano: The Development of the Concept of Intentionality." In H. Blumenthal and H. Robinson (eds.), Aristotle and the Later Tradition (Oxford Studies in Ancient Philosophy, supplementary volume). Oxford: Clarendon Press.

Sorabji, R. (1992). "Intentionality and Physiological Processes: Aristotle's Theory of Sense-Perception." In M. C. Nussbaum and A. O. Rorty (eds.), Essays on Aristotle's De Anima. Oxford: Clarendon Press, 195–225.

Trubowitz, J. (2025). "Aristotle on Perceptual Self-Consciousness." Archiv für Geschichte der Philosophie (advance online publication).