Dualism’s Categorical Mistake

K VII, László Moholy-Nagy

In his book The Concept of Mind (University of Chicago Press, 2000), Gilbert Ryle dismantles René Descartes’ theory of dualism, which treats mind and body as distinct, correlating channels acting in the same conceptual space. The problem of Cartesian Dualism, according to Ryle, is that it enforces a “category-mistake,” supposing that mind and body are distinct and equal when they are not of the same logical category. Like Ryle, I argue that there is a logical error in conceptualizing the mind and body as coexisting in separate channels on the same logical plane. Firstly, mind is of a higher category than body because it subsumes all bodily purpose and function. Secondly, there is no true reciprocity between mind and body, because that would suppose that mind and body are separate, yet equal entities. And, thirdly, if we are to believe that consciousness pervades bodily function through human subjectivity, then, as an aspect of mind, it cannot exist out of the body, cementing the superior role of mind to body. Ryle negates the assumption that there are two different kinds of existences, one of the mind and one of the body, as evidenced by his criticism of the “dogma of the ghost in the machine.”

Placing direct, neurological dictation of the body aside, Ryle considers the superiority of mind over body while the mind holds a non-spatial position. The main issue of mechanical causation of corporeal movements and corporeal causes of corporeal movements is that it leaves us wanting a mental and, as dualists would have it, immaterial equivalent. Ryle states, “Since mental-conduct words are not to be construed as signifying the occurrence of mechanical processes, they must be construed as signifying the occurrence of non-mechanical processes; since mechanical laws explain movements in space as the effects of other movements in space, other laws must explain some of the non-spatial workings of minds as the effects of other non-spatial workings of minds.”

Again, this is a major component of the categorical mistake Ryle suggests because we cannot compare mechanical or non-mechanical processes by their spatial/non-spatial causes. Mind and matter are whole, but if mind governs body, the difference in causation—be it between mechanical and non-mechanical movement or between intelligent and unintelligent behavior—is irrelevant. Dualists believe that mechanical causation of corporeal movements and corporeal causes of corporeal movements exist, but there needs to be a non-mechanical, mental causation that is yet to be discovered. Anything else would be disproportionate to the relationship between mind and body. Ryle adds, “As the human body is a complex organized unit, so the human mind must be another complex organized unit, though one made of a different sort of stuff and with a different sort of structure. Or, again, as the human body, like any other parcel of matter, is a field of causes and effects so the mind must be another field of causes and effects, thought not (Heaven be praised) mechanical causes and effects.” Summarized: the physical world, the space in which we externally interact with others, does not find its mental parallel in an internal, private world of the mind.

A possible root of Ryle’s issue with Cartesian Dualism is the idea of a reciprocal relationship between mind and body, which further poses Descartes’ theory of distinct channels. Both Descartes and Ryle agree that there is correspondence between mind and body as there is a clear relationship between the two. The difference between Ryle’s theory and the dualist perspective is the treatment of this relationship as reciprocal rather than corresponding. The former reciprocal view suggests that mind and body are the same; the latter merely affirms the relationship between the two without indicating that they are of the same logical type.

To use Ryle’s example, just as there is a relationship between the University of Oxford and the Bodleian Library, there, too is a relationship between mind and body. However, as he states, “A mind’s reports of its own affairs have a certainty superior to the best that is possessed by its reports of matters in the physical world. Sense-perceptions can, but consciousness and introspection cannot, be mistaken or confused.” The mechanical processes of our brains can make alterations in our physical world just as our physical world can cause us to modify our thoughts or beliefs. Mental states are not separable from physical states, and thus should not be treated as such when considering their relationship.

Stating that he does not deny the occurrence of mental processes, Ryle argues that they must be classified accordingly when we discuss their mechanical and non-mechanical aspects: “I am not, for example denying that there occur mental processes. Doing long division is a mental process and so is telling a joke. But I am saying that the phrase ‘there occur mental processes’ does not mean the same sort of thing as ‘there occur physical processes,’ and, therefore, that it makes no sense to conjoin or disjoin the two.” This leads us to Ryle’s argument on what he refers to as a “dogma of the Ghost in the machine” or the “double-life theory” he attributes to dualism. Ryle argues that there cannot be two different kinds of existences—one of the mind and one of the body—because it would lead to the “bifurcation” of an individual’s two lives. A dualistic philosophy promotes the mind-body relationship as one that acts discretely, suggesting that there either exists a mind or a body, but not both. He denies the idea that minds are merely ghosts that dwell in machine-like bodies because mental phenomena explain the mechanical workings of the body. To Ryle, the mind-body relationship is a hybrid engine as “…minds are not merely ghosts harnessed to machines,” but are spectral machines themselves. He continues, “Though the human body is an engine, it is not quite an ordinary engine, since some of its inner workings are governed by another engine inside it—this interior governor-engine being one of a very special sort.”

Ryle understands that this antithetical view of mind and body may be strictly metaphorical, but, as he states, “Even when ‘inner’ and ‘outer’ are construed as metaphors, the problem how a person’s mind and body influence one another is notoriously charged with theoretical difficulties …the actual transactions between the episodes of the private history and those of the public history remain mysterious, since by definition they can belong to neither series…” There are larger implications to the underlying theoretical issues at hand. Dualism assumes that there are different kinds of existences, either having the status of a mental existence or a physical existence; so mental images are bound within the mind. However, dispositions and abilities like memory or imagination are not bound by the mental space conceived by a dualistic model and mental existence does not have to fall into the confines of mind.

Ryle uses the coin example as a point of comparison: “Somewhat as the faces of coins are either heads or tails, or somewhat as living creatures are either male or female, so, it is supposed, some existing is physical existing, other existing is mental existing.” Dualism is thus falling into a dangerous dichotomy that isolates mind from body and categorizes the two as equal. Further grounding his argument in semantics, Ryle illustrates the absurdity of conjoining these terms of different types through his left-hand and right-hand glove example: “…a purchaser may say that he bought a left-hand glove and a right-hand glove, but not that he bought a left-hand glove, a right-hand glove and a pair of gloves.” Given the context of Cartesian Dualism, the conjunctive proposition likens the two entities as similar in type, yet the disjunctive isolates them, which is both contradictory and counterintuitive.

Ryle’s critique of Cartesian Dualism and the theory of mind and body as two distinct entities is founded in his theory of dualism’s categorical mistake. According to him, the traditional definition in classical theory of mind upholds the distinction between mind and matter, a relationship that cannot be analyzed in a reciprocal fashion because they are incompatible as equal types. He argues against the reduction of mental reality to physical reality, because although mind arguably is superior to the body and governs it, it cannot be defined in the same mechanical terms. Similarly, material reality and sensation cannot be defined through idealistic terms. To be in one’s body is to be in one’s mind, as mind contains the various sensations and neurological and conscious elements found in the body. It’s important to note that mental states are not separable from physical states, but to Ryle, their collaboration is elusive. Consciousness, he argues, encompasses all mental and bodily sensation, including the dispositions and abilities that exist beyond the mind.