Hobbes’s Mechanical Phantasms and the Material Mind

Philosopher Thomas Hobbes advances the first thoroughgoing materialist account of mind in the modern period: whatever exists is body, whatever changes is motion, and sensation is nothing but a motion in the sentient produced by the pressure of an external body and returned as an outward endeavour, or reaction, in the organ of sense (Hobbes, 1655/1839, De Corpore 25.2). The felt content of that reaction—color, sound, heat, pain—he calls a phantasm, fancy, or seeming, and it lies not in the object but in the perceiver, so that sense in every case is nothing but original fancy caused by the pressure of external things upon the organs (Hobbes, 1651/1996, Leviathan 1.4). Hobbes does not use "consciousness" in anything like the modern phenomenal sense; he preserves its etymological meaning of knowledge shared between witnesses and regards private conscience as politically dangerous (Leviathan 7.4, 29.7). What he supplies instead is an account of phenomenal awareness in which appearance is real, wholly corporeal, and identical with a motion in the body—a position with no immaterial remainder and no acknowledged explanatory gap.

In other words, Hobbes’s pioneering, systematic materialist theory of mind and phenomenal experience posits that sensation, imagination, memory, thought, emotion, and deliberation are all activities of an embodied organism and ultimately explicable through matter and motion, without an immaterial soul. Sensory consciousness begins when motions originating in external bodies propagate through the sense organs and inward to the brain and heart, producing this counter-motion or “endeavour” whose subjective manifestation is this seeming, fancy, or phantasm; imagination and memory are continuations of these sensory motions after their external causes have disappeared (Hobbes, 1651/1996; Hobbes, 1655/1839). Hobbes’s theory constitutes a remarkably early attempt to naturalize phenomenal awareness itself—while leaving unresolved the fundamental question of why or how motions in matter should constitute the qualitative appearances they produce.

A Material Mind in a Mechanical World

Hobbes’s philosophy of mind follows from his uncompromising corporealism. By the mature works Leviathan and De Corpore, human beings, including their minds, are wholly material; talk of an “incorporeal substance” is, for Hobbes, conceptually confused because whatever genuinely exists is body (Hobbes, 1651/1996; Hobbes, 1655/1839). Against Cartesian substance dualism, thinking therefore requires no separate res cogitans: matter organized as a living human or animal can sense, imagine, desire, and think. Hobbes’s materialism is thus stronger than the later epistemic agnosticism of Locke—Hobbes explicitly denies that mental activity requires any nonphysical bearer.

His psychology is correspondingly empiricist and mechanistic. All conceptions originate directly or indirectly in sensation; imagination preserves or recombines sensory contents; linguistic signs permit more elaborate thought; and reasoning consists in forms of “reckoning” or computation with names (Hobbes, 1651/1996; Hobbes, 1655/1839; Pettit, 2009). Animals likewise sense, imagine, remember, and exhibit forms of understanding, whereas human linguistic capacities enormously amplify cognition. Hobbes thus tries to explain the entire hierarchy of mental capacities by transformations of fundamentally sensory-material processes rather than by introducing a distinct rational soul.

Bodies in Motion and the Rejection of Incorporeal Substance

For Hobbes, to exist is to be a body: to have magnitude and to occupy place. "Incorporeal substance" is therefore not a mysterious posit but a contradiction, two names whose significations are inconsistent, and so an utterance signifying nothing at all (Leviathan 4.21). Duncan (2022) notes that Hobbes's position is more precisely described as corporealism than as materialism in the later sense, since it is framed in terms of corpus rather than matter, but the consequence for mind is the same. There is nothing for a mental state to be except a motion in a body, and questions of union, interaction, or divine additions never arise.

The commitment is sharpest in Hobbes's contribution to the Third Set of Objections to Descartes's Meditations. Granting that I am thinking, Hobbes asks what licenses the inference that the thing which thinks is immaterial. One might as well infer from "I am walking" that there is an incorporeal walker; the subject to which mind and reason belong may perfectly well be corporeal (Descartes, 1641/1984, CSM II 122). Descartes's reply, that Hobbes has confused a substance with its accidents, did not persuade, and the exchange remains a founding document of the materialist position on mind (Adams, 2014; Ross, 1988).

The Phantasm: Pressure, Endeavour, and Reaction

The mechanism is uniform. An external body presses the organ; the pressure travels inward by nerves to the brain and heart; there it meets a resistance, a counter-pressure or endeavour of the heart to deliver itself outward. The phantasm is made by that reaction and endeavour outwards, caused by an endeavour inwards from the object, and remains for some time after the object is gone (De Corpore 25.2). Because the reaction is directed outward, the appearance presents itself as external—Hobbes's mechanical attempt to explain why experience seems to be of a world rather than of the organ, a demand later theories have more often deferred than met.

The same mechanics carries through the whole mental faculties. Imagination is decaying sense, the motion persisting and weakening after its cause is removed; memory is that identical decaying motion noticed as past; dreams are imagination in sleep, vivid because no external motions compete with them (Leviathan 2.2–2.5). Trains of thought are sequences of such motions, governed by the order in which they were first produced. Hobbes thus offers a single dynamical account covering sensation, imagery, recollection, dreaming, deliberation, and passion, with no gap psychology and no residue requiring separate explanation.

Sense as Seeming and the Location of Sensible Qualities

Hobbes argues that sensible qualities are not in objects. Colors and sounds can be severed from their sources by mirrors and echoes, where the thing seen is in one place and the appearance in another; the object is one thing, the image or fancy another (Leviathan 1.5). In the object these qualities are only motions of matter, and in us likewise only motions, for motion produces nothing but motion. This radicalizes the Galilean demotion of secondary qualities: Hobbes does not merely deny that redness resembles anything in the object, he identifies the appearance itself with a bodily motion. Read strictly, that is an identity claim about phenomenal quality advanced two and a half centuries before Place and Smart, and the strongest reason for treating Hobbes as the ancestor of mind-brain identity theory rather than merely of mechanistic psychology.

The reading is contested. Leijenhorst (2002) argues that Hobbes operates with a twofold notion of accident—realist for primary qualities, phenomenalist for secondary—which would make phantasms modes of the perceiver rather than straightforward identities. Duncan (2024) is skeptical, noting that Hobbes nowhere says powers are aggregates of phantasms. What is not in dispute is that the felt quality is relocated wholly inside the sentient body.

Memory, Discrimination, and Whether Hobbes Has a Theory of Consciousness

Asked how we take notice of sense, Hobbes answers: by sense itself, by the memory that remains in us of things sensible after they pass away, for he that perceives that he has perceived, remembers (De Corpore 25.1). Sense therefore has memory adhering to it, since without retention nothing could be compared or distinguished, and to sense always the same thing and not to sense at all come to the same. Awareness, on this account, requires difference—an anticipation of habituation, sensory adaptation, and contemporary proposals tying consciousness to change and prediction error.

Whether this directly constitutes a theory of consciousness is doubtful. Jorgensen (2025) cautions that sensing is itself already an appearance, so the appeal to memory may explain the unity of experience over time rather than what makes any episode felt. Frost (2005) reads the passage as the basis of a materialist self-consciousness; Ross (1988) situates Hobbes's resistance to a higher-order construal within his account of language, on which reason and distinctively human thought depend on speech while sense does not.

Panpsychism, Publicity, and Assessment

The mechanism generates a kind of embarrassment Hobbes saw clearly. If sense just is reaction to pressure, and all bodies react, then all bodies sense. He restricts sense proper by requiring organs and retention, but the restriction looks contrived, and Sorell (1986) concludes that some form of panpsychism is hard to rule out on Hobbes's premises. Cavendish and Henry More both pressed the point directly (Duncan, 2012). Meanwhile Hobbes's own term for consciousness remains resolutely public: when two or more know one and the same fact, they are conscious of it to one another, and the private extension is a rhetorical metaphor (Leviathan 7.4).

The deficits are plain. Hobbes gives no argument why motion should feel like anything, and never registers the question as one requiring an answer; the identity of phantasm with motion is asserted rather than argued. His discrimination requirement does some work but is never developed into a criterion for which bodies sense. What he establishes instead is the shape of the modern materialist program—experience as a physical process, sensible quality relocated to the perceiver, mental life unified under one dynamics, and the burden of proof shifted to those who would posit anything further.

References

Adams, M. P. (2014). The wax and the mechanical mind: Reexamining Hobbes's objections to Descartes's Meditations. British Journal for the History of Philosophy, 22(3), 403–424.

Descartes, R. (1641/1984). Meditations on First Philosophy, with Objections and Replies. In J. Cottingham, R. Stoothoff, & D. Murdoch (Trans.), The Philosophical Writings of Descartes (Vol. 2). Cambridge: Cambridge University Press. [Cited as CSM II, by page.]

Duncan, S. (2012). Debating materialism: Cavendish, Hobbes, and More. History of Philosophy Quarterly, 29(4), 391–409.

Duncan, S. (2022). Materialism from Hobbes to Locke. New York: Oxford University Press.

Duncan, S. (2024). Hobbes on powers, accidents, and motions. In S. Bender & D. Perler (Eds.), Powers and Abilities in Early Modern Philosophy (pp. 126–145). New York: Routledge.

Frost, S. (2005). Hobbes and the matter of self-consciousness. Political Theory, 33(4), 495–517.

Hobbes, T. (1651/1996). Leviathan (J. C. A. Gaskin, Ed.). Oxford: Oxford University Press. [Cited by chapter and paragraph: 7.4 = chapter 7, paragraph 4.]

Hobbes, T. (1655/1839). De Corpore. In W. Molesworth (Ed.), The English Works of Thomas Hobbes (Vol. 1). London: John Bohn. [Cited by chapter and section: 25.2 = chapter 25, section 2.]

Jorgensen, L. M. (2025). Seventeenth-century theories of consciousness. In E. N. Zalta & U. Nodelman (Eds.), The Stanford Encyclopedia of Philosophy.

Leijenhorst, C. (2002). The Mechanisation of Aristotelianism: The Late Aristotelian Setting of Thomas Hobbes's Natural Philosophy. Leiden: Brill.

Ross, G. M. (1988). Hobbes and Descartes on the relation between language and consciousness. Synthese, 75(2), 217–229.

Sorell, T. (1986). Hobbes. London: Routledge & Kegan Paul.