Ghost in the Machine

March 2017 Pulse

One of the most puzzling questions that continue to plague philosophers of mind is the relationship between mind and body. In a philosophical ethos where physicalist accounts of reality seem to be the new orthodoxy, phenomena such as consciousness continue to fascinate and baffle our best minds.

‘How can there be such a thing as consciousness in a physical world, a world consisting ultimately of nothing but bits of matter distributed over space-time behaving in according to physical law?’, inquires the philosopher of mind, Jaegwon Kim, in his book entitled, Physicalism or Something Near Enough (2005).

Colin McGinn wrestles with the same problem when he asks: ‘How could the aggregation of millions of individually insentient neurons generate subjective awareness? We know that brains are de facto causal basis of consciousness, but we have, it seems, no understanding whatever of how this can be so’.

Modern discussions on the relationship between mind and body can be said to be mostly reactions and responses to Cartesian dualism.

The 17th century philosopher, Rene Descartes, drove a wedge between the mind and the body when he argued that ‘we clearly perceive the mind, that is, a thinking substance, apart from the body, that is, an extended substance’. By making the fundamental distinction between the res cogitans and the res extensa, Descartes is proposing a substance dualism, separating mind and body.

This has prompted the British philosopher, Gilbert Ryle, to describe Descartes’ dualism memorably as the ‘ghost in the machine’ in his book, The Concept of Mind (1949).

Cartesian dualism is of course not new. It may be seen as a modern version of the more ancient Platonic dualism that conceives of the eternal soul as a distinct substance from the temporal physical body.

Attempts to surmount or eradicate such dualisms have led, as mentioned above, to privileging the physicalist view where the mind is reduced to the brain and where mental states are simply attributed to neurons and synapses.

Dissatisfied with the solution suggested by physicalism, thinkers like Nancy Murphy have proposed another way of understanding the mind-body relationship that is rather clumsily described as ‘non-reductive physicalism’.

According to this theory, while mental properties are closely related to and in some sense dependent on physical properties, they should not be confused with them. Mental properties must be seen to supervene physical ones just as the aesthetic qualities of a painting (its beauty and elegance) can be said to supervene the physical ones (paint and canvas).

For reasons that I cannot discuss within the short compass of this article, both types of physicalism have been found wanting by some philosophers and theologians.

There is, however, another way of understanding the relationship between mind and body that avoids dualism on the one hand and physicalism on the other. Technically termed as hylomorphism (Greek: hule = matter and morphe = form), this theory can be traced to another ancient Greek philosopher: Aristotle.

Aristotle begins on the premise that every physical object is a compound of form and matter. The form, he goes on to argue, is the actualising principle that directs and energises matter, enabling it to achieve its true potential.

The soul therefore, as the principle of life, defines the existence and life of a being. (Aristotle believes that all living beings, including plants, have souls appropriate to their kind). While the physical body of the animal may change, the soul (or form) remains the same. The soul retains the integrity of the living being and enables the exercise of its faculties.

As University of Chicago philosopher Martha Nussbaum explains: ‘The lion may change its shape, get thin or fat, without ceasing to be the same lion; its form is not its shape but its soul, the set of vital capacities, the functional organisation, in virtue of which it lives and acts’.

Applying this to human beings, Aristotle postulates that the soul is the form of the body. That is, the soul is the principle of life that makes the human being the kind of creature it is – it gives it integrity. For Aristotle, the soul refers to all living processes, including mental capacities.

In light of the modern mind-body debate, hylomorphism can be said to be a salutary alternative to dualism and physicalism.

In contrast to the dualistic view (Platonic or Cartesian), which sees the soul (mind) and body as two distinct substances, hylomorphism establishes the closest possible relationship between the two.

The great medieval theologian, Thomas Aquinas, who applies hylomorphic metaphysics to his anthropology states that ‘the body and the soul and not two actually existing substances; rather, the two of them together constitute one actually existing substance’. Thus, neither the soul by itself nor the body by itself have ‘the complete nature of its species’, according to Aquinas.

While hylomorphists agree with the physicalists (of both reductive or non-reductive varieties) that the physical aspects of the human are important, they reject the latter’s theory of supervenience, which postulates that higher mental properties are dependent on and even determined by lower physical ones.

Supervenience has led Christian philosophers like Nancy Murphy to see the traditional concept of the soul as no longer meaningful.

Hylomorphism is therefore able to present a more holistic conception of the mind-body relationship.

It prevents the mind and the body from drifting apart. It prevents the instrumentalization of the body (in the Cartesian sense of the body as merely the extension of the mind).

Significantly, hylomorphism provides a more profound account of the nature of human actions. Human actions are never seen as having either mental or physical causalities but as the agency of the whole person.



Dr Roland Chia is Chew Hock Hin Professor of Christian Doctrine at Trinity Theological College and Theological and Research Advisor for the Ethos Institute for Public Christianity.