The Strengths and Weaknesses of Dualism

Dualism is the belief that reality consists of two different, separate substances: that of the mental and that of the physical. “In philosophy of mind, the belief that the mental and physical are deeply different in kind: thus the mental is at least not identical with the physical.” It directly opposes materialism, as dualism dictates that the mind is unidentifiable to the body, as opposed to stating that the mind and body exist as one. The concept of dualism is not only fundamental in philosophy, but also affects our thoughts on science, religion and psychology: for example, if a convincing rejection of dualism can be formulated, the materialist approach of modern science will be vindicated. If, conversely, dualism can be convincingly maintained, then our evidence obtained from studies of the brain would simply not suffice in gaining any form of insight into the human mind.

Dualism is a logical necessity: sustained as a question that does not need to be answered as it can be fulfilled a priori, owing to the fact that humans have the ability to seek introspection regularly. Indeed, we experience the separation between our body and mind, which would support the notion that they are separate entities and empirical evidence is not required to prove such a concept. However, this does not mean that dualistic theory is foolproof: for example, can our experience be enough to prove such a concept? Indeed, many philosophers are not in favour of dualistic ontology. In the course of addressing this question, the origins of the mind and body problem will be discussed, which will then permit a fully focussed evaluation of the strengths and weaknesses of Cartesian Interactionist Dualism.

Whilst looking at the support for Descartes’ theory I will explore arguments from Madell, David Chalmers and T.H Huxley amongst others. Conversely, whilst addressing the criticism of Interactionist Dualism, I will explore the works of Ryle, Hume and Williams. Finally, the wider implications that dualism has upon two prominent world religions will be addressed, with an examination of the relationship between dualistic theory and the afterlife in Christianity, Hinduism and Islam.

The first classical representation of dualism can be recognised in Plato’s work; more specifically originating in The Phaedo. Interestingly, in dualism, ‘mind’ is contrasted with ‘body’, but in different historical periods, different aspects of the mind have been the centre of attention.
For example, in the classical period it was the intellect of the mind which was considered to be the crux of what separated us from the physical. However, from Descartes onwards, the opposition to materialism came from our apparent ‘consicousness’ and experience of ‘sensation’. The emphasis on intellect is certainly echoed in Plato’s work: as he believed (as did many other Greeks) that the body was a prison for the intellectual soul. Indeed Plato believed that the true substances are not physical bodies, which are ephemeral, but the eternal Forms of which bodies are imperfect copies. He came up with the idea of a realm of “Forms” and said that intellect was immaterial, for it does not last you, therefore Forms are immaterial, and thus intellect must link to those that it apprehends.

He then continued to say that such a link forced the soul to want to leave the body to enter a realm of Forms. In his later writings, The Republic, Plato furthered his ideas on Forms and the soul; he claimed that not only was the soul the true form but belonged to a higher status within reality than the body did, and that the soul was a separate, immortal substance. Plato’s study of dualism in The Phaedo was indeed complex, and more a metaphysical study regarding the imprisoned soul. However, it can be seen, especially amongst his writings in The Republic, that Plato was clear on his belief that the body and soul were separate entities, forming the base for philosophical extensions in more recent times.

Continuing from Plato, St Thomas Aquinas extended earlier works on dualism in his endeavour to unite philosophy with proof of God. Aquinas agreed with the Artistotlean notion that when the soul entered the body it animated it and gave it life; calling it anima. Moreover according to Aquinas, the soul operates independently of the body and it cannot decay; for only things that can break into parts can decay, Thus, following Aquinas’ argument, the soul is able to survive death. He also said that through the link with a particular human body, each soul becomes individual. So, even when a body dies, the soul that departs retains the individual identity of the body to which it was attached.

Despite this earlier work, there was still no explanation of how the soul and body worked together, if at all. This was until Descartes (1596- 1650) who provided the fundamental writings on dualism with his work Meditiations on First Philosophy. Indeed, he is considered “the father of modern philosophy” and his Meditations lead to the school of dualistic ontology known as Cartesian Interactionist Dualism, which still inspires much thought and extension by modern philosophers today. Descartes defined the ‘mind’ as “all the feelings and sensations that he could describe, but which he could not locate physically”. He then furthered this by saying that the mind is everything that is non-physical.

“Then without doubt I exist also if he deceives me, and let him deceive me as much as he will, he can never cause me to be nothing so long as I think I am something… it might possibly be the case if I ceased entirely to think, that I should likewise cease altogether to exist.”

This extract leads to Descartes’ conclusion: ” I think therefore I am”; that the mind and body are separate entities, they do interact, but it is the mind that is superior to the body as it is that which creates the self.

Descartes had to provide a complex explanation as to how the mind and body, from such separate realms, could “causally interact”. He suggested that the mind deflects the flow of physical currents within the body and thus has an influence on the mechanical workings of it. Therefore, Descartes is implying that the mind and body are separate entities but part of one; thus enabling them to interact. Furthermore, as the mental realm is not empirical it is thus not part of this world, and this supports the idea that it is possible for the mind to exist without the body:

“I posses a body with which I am intimately conjoined, yet because, on the one side, I have a clear and distinct idea of myself in as much as I am only a thinking and unextended thing… it is certain that this I (that is to say my soul by which I am what I am) is entirely and absolutely distinct from my body, an can exist without it.”

Descartes extends upon this by reasoning that if the mind is the essence of one’s identity and that we do not need our bodies to live an intellectually aware and active life; then it is therefore plausible to believe that the mind can survive the death of the body: essentially that the soul is immortal. Descartes related this school of philosophical thought to his personal belief in God; he considered that when an individual dies, their soul is able to continue with God after death, as the same individual who had existed in their physical form on Earth:

“Our soul is of a nature entirely independent of the body, and consequently… it is not bound to die with it. And since we cannot see any other causes which destroy the soul, we are naturally led to conclude that it is immortal.”

Therefore, the main ideas of Cartesian dualism can be summarised as follows: that the mind is a ‘non-corporeal’ substance, which is distinct from material or bodily substance; indeed that they are different things. Secondly, that every substance has a property or a special character: for example, the mind substance’s property is consciousness, and the property of bodily substance is length, breadth or depth. The mind is a substance ‘whose whole essence is to think’ and so takes up no space. The body is material, whose essence is to take up place. Thirdly, that the body is an extension of the true self, the mind, and it is the material aspect of the self which has extensional features. Thus, finally that these two substances interact with each other, as the mind can cause events to occur in the body and the body can cause events to occur in the mind.

An extension of Descartes’ ideas can be shown clearly in Leibniz’s Reply to Bayle:

“But in the general principles which establish the monads of which compound things are merely the results, internal experience refutes the Epicurean doctrine. This experience is the consciousness which is in us of this which apperceives things which occur in the body. This perception cannot be explained by figures and movements.”

Indeed, Leibniz agreed with Descartes in that the mind and body belong to two separate realms; however Leibniz rejected the idea that the mind and body, two separate substances could causally interact (inter-substantial causality), and instead asserted a “pre-established harmony doctrine”: essentially the crux of his argument for parallelism. Within this Leibniz explored his belief that there was only one substance in the world and that mind and body were part of this same substance and that, conversely they could interact: (intra-substantial causality). Leibniz likens the process to two clocks being set by God that run at the same time, but do not influence each other. Once God has set the clock running, as it were, the parallel relationship has been created and continues onwards without further intervention. In relation to dualism he reasoned that created minds and bodies are therefore created so that all their actions and states occur in mutual coordination, thus explaining his denial of mind-body interaction and asserting the principle of pre-established harmony.

The period of time for which the dualistic argument has stood, as (arguably) a respected philosophical theory is a testament to its strength and accessibility of argument. Indeed, the first philosophically formulated argument in favour of Cartesian Dualism is known as the Argument from Personal Identity, most successfully argued by Geoffrey Madell. He looked at the problems and consequences of identity owing to the origin; and argued that the way we address material objects cannot be applied to people and their minds (counterfactuals). For example three counterfactual statements can be made about a table:

This table might have been made of ice.

This table might have been made of a different sort of wood.

This table might have been made of 95% of the wood it was made of and 5% of some other wood.

This scale of counterfactual possibilities illustrates how there can be such an extent of possibilities that it would be impossible to identify whether the table being described is the table that actually exists. In relation to personal identity: suppose that a given human individual had had origins different from those which he in fact had such that whether that difference affected who he was was not obvious to intuition. What would count as such a case might be a matter of controversy, but there must be one. Perhaps it is unclear whether, if there had been a counterpart to Jones’ body from the same egg but a different (though genetically identical) sperm from the same father, the person there embodied would have been Jones.

Some philosophers might regard it as obvious that sameness of sperm is essential to the identity of a human body and to personal identity. In that case imagine a counterpart sperm in which some of the molecules in the sperm are different; would that be the same sperm? If one pursues the matter far enough there will be indeterminacy which will infect that of the resulting body. There must therefore be some difference such that neither natural language nor intuition tells us whether the difference alters the identity of the human body; a point, that is, where the question of whether we have the same body is not a matter of fact. Essentially, this supports the notion of dualism in that, to a certain extent, it proves that the ‘mind’, the ‘identity’ are separate from the physical body and cannot be treated in the same way.

Chalmers’ addressal of ‘the hard problem’of how conscious experience can be examined with reference to the human brain is certainly another proposed strength of dualism. He argued that the dichtomy between the brain and the complex mind is such that science will never be able to dicipher it, and that instead we should look for a different explanation in consciousness; essentially we have to accept that answering the ‘hard problem’ requires going beyond the physical:

“Once we accept that materialism is false, it becomes clear that… we have to look for a “Y-factor,” something additional to the physical facts that will help explain consciousness. We find such a Y-factor in the postulation of irreducible psychophysical laws”

Therefore, it can be seen that Chalmers strengthens dualist ontology in his argument that science will never be able to conquer the brain and explain the workings of the mind, nor can our physical activities; thus dualism is the only plausible explanation.

The Knowledge argument presents another strength for the dualistic argument. Essentially, it supports dualism by directly rejecting physicalism. It can be put in abstract as such: one might know all the objective, physical facts about human conscious experiences, and yet fail to know certain facts about what human conscious experiences are like subjectively; therefore, there are facts about human conscious experiences that are left out of the physicalist’s story, and so physicalism is false. For example, say an individual is colour blind; but knows about colour, the properties of light, and every fact about the physicality of seeing colour.

Suppose that this individual has an operation on their eyes; the expectancy is that the individual will learn something from their newly gained vision. These qualitative features of experience are generally referred to as qualia, and support dualism in that they suggest the existence of an unphysical consciousness, entirely separate from the body: that is the mind or soul. However, this argument can be counteracted by the work of T.H.Huxley who stated that the conscious mind is an epiphenomenon; essentially a by-product of the physical system (the brain) which has no influence back on it.

Dualism is strengthened by the ease in which it fits into human nature and lifestyle. As Paul Churchland reflects:

“It is the most common theory of mind in the public at large. It is deeply entrenched in most of the world’s popular religions, and it has been the dominant theory of mind for most of Western history”

Its domination and worldwide acceptance give an insight into the importance of life after death as a human need. Indeed, it is an attractive concept for us to believe that our souls are so intelligible and different from our functioning bodies that they can defeat death. Many seek solace in their belief in dualism, especially during times of mourning, and this willingness to believe in the immortality of the soul further strengthens the argument that personal identity is confined to the non-physical, as opposed to the body. Additionally, dualism is popular, because it answers why it is possible to be using your mind, without any bodily functions. Indeed, dualism is popular because it provides logical answers to these questions; and such popularity empowers dualism as a philosophical concept.

Despite this, there has been much criticism of dualism and indeed there are many flaws in the Cartesian argument: the first of which to be explored is The Argument From Causal Interaction. This argument focuses upon the flaw in Descartes’ alleged “causal interaction”: (that the mind and body are separate entities that causally interact); and uses physics to undermine it. It essentially states that conservation of energy is a fundamental scientific law; and yet if causal power were flowing in and out of the physical system, energy would not be conserved. Physics cannot support dualistic ontology; however, the argument against interactionism can also be criticised simply through principle. This argues that if the mind and body are from such separate realms then “they lack that communality necessary for interaction” Indeed, it suggests that the two substances are so radically different that it is impossible for the two to “causally interact”.

Another critic of Cartesian dualism was Gilbert Ryle, a behaviourist who outlined his arguments in The concept of the mind . Initially, Ryle claims that Descartes is wrong to think that our outward actions or behaviour is evidence for an inner state that causes our behaviour. In Ryle’s example of attentive listening, dualism dictates that this should be two acts: first, the physical hearing of the sound; and secondly, the mental process of “attending” which causes our listening to be attentive. Yet, according to Ryle, in describing a person’s mind we are describing the ways in which parts of his or her conduct are managed. A person is not listening as a physical action, and being attentive by a mental action, he argues that there is merely one process characterised as ‘attentive listening’.

Ryle says that by using psychological predicates as reference to a private mental item, we are making a category mistake. To explain why he thought it was a category mistake to describe the body and mind as two separate entities, and to express the soul as an entity identifiably extra to a person he used the analogy of a foreign person watching a cricket match. Say they were to ask: ” where is the team spirit?”; the question is posed in such a way that they expect the answer to be, that the team spirit is some identifiably extra to the team, which it is not. Thus, Ryle used this concept to say that the soul is not something that is unidentifiably extra to the body; essentially exposing a flaw in Descartes’ argument.

Bernard Williams is a third philosopher who offered a critique of dualism. Essentially, Williams argued against the argument from personal identity, and rejected the notion that our body is simply a physical casing and that the crux of our existence is our mind, including the various actions and memories within it. Instead, he suggested that memories are a poor guide to identity. He claimed that memories could be fabricated and that personal identity cannot be proved through mental activity alone. Indeed, they are not infallible: four people giving accounts of a dinner party may all provide quite different versions of events; our memories are selective, allowing us to recall information that is most relevant to ourselves . Williams then went on to say that identity depends on recognition and therefore without the body one cannot be identified.

Hume’s application of Bundle Theory to the mind and our notion of identity offers a capable critique of dualism. The bundle theory of ontology asserts that objects are a bundle of their properties. The object itself therefore cannot exist separately from its properties; the object is its collected properties. Hume asserts that the individual is a product of their thoughts, memories and experiences. However when he attempts to introspect the nature of the self that owns and feels these experiences he comes up empty handed. He thus concludes that there is no ‘I’ or owner of these experiences, just a set of experiences related by “resemblance, contiguity in time or place, and Cause or Effect” . Thus, objects don’t exist: there are only bundles of properties and identities don’t exist: there are only bundles of experiences. This highlights and reinforces the primacy of the mental over the physical as even in denying the existence of the self, it is the mind that defines the bundle that is ‘us’. This sense of superiority of the mind over the body, and indeed the separateness of the two in dealing with this theory, suggests that the mind and body are separate.

However, this can be counter-argued: for example, Hume proposed no alternative to identity; secondly, there is no mention of a collector of the bundle. In the same way that properties must be of something, experiences must have been experienced by something; and neither have existence in their own right, but are dependent on an entity that exists in space and time. If Hume’s ideas on identity are correct then this implies to the philosopher a dichotomy between body and soul; thus criticising Cartesian Dualism. Furthermore, a critical question regarding Cartesian dualism is often raised about how the mind, with all its various elements, can be unified without a common uniting substance: essentially the frameworks of the Bundle Theory. Hume, who addressed this problem, said that aspects of agency in the sense of bodily actions, such as judging, are regarded as mere awareness of bodily actions. However, for Cartesian dualism this is still a flaw, as the theory not only suggests that the mind cannot exist alone but also suggests that bodily actions have little to do with the mental; contradicting Cartesian belief of “causal interaction”.

Aside from the published critique of dualistic ontology, there are also commonly recognised flaws within Descartes’ argument. Perhaps the first weakness is that any works on dualism are a priori and therefore can never be empirically qualified. Indeed, the lacking of empirical data to back up a theory is always a weakness within any presented argument, and this view was upheld and extended by the Logical Positivists in 1920. They held that it was meaningless to talk about anything that could not be empirically verified; thus any talk of God, or even such things as ‘the soul’ was fruitless and a waste of time. However, even if when we look at dualism with solely a priori information we find faults within it through our very experience. For example, humans commonly experience interaction between the mind and body; almost every day. Upon the consumption of alcohol, in Cartesian theory this should only affect the body, however it is known that it affects the mind in its alteration of personality, behaviour and perception.

Additionally, we experience interaction between the two substances in the other direction: when something is bothering our mind, we almost immediately notice it in our health and physical state. For example, recent research demonstrates that 90% of illness is stress-related . Moreover, when our minds are under stress, our bodies can potentially experience headaches, skin problems, high blood pressure, diabetes and impotence. Such symptoms give strong evidence that what affects the mind, also affects the body. Another basic challenge to dualism questions how, if the mind is non-physical, it can make anything happen in the physical realm. For example, how are we to stand up from our chair, or indeed know that we have, if our mind is not intrinsically linked to our body.

Furthermore, many scientists completely reject dualism, as they see the brain and mind (the physical and alleged “non-physical”) as completely dependent on each other. For example, as the brain develops in infancy, so does the mind; when the brain suffers injury, the mind too is affected, suggesting an interaction much more than simply “causal”. Smaller weaknesses in Cartesian theory question the dualistic ontology in other organisms aside from humans. Descartes supposes that animals belong in the category of Mind-less, purely physical things. However, this argument may be seen as flawed in our modern day understanding of evolution, and the similarity between the higher apes and human beings.

Dualism is certainly relevant within religion, and indeed a religion’s affiliation to such ontology can strengthen the argument a great deal. In Hinduism, the self is known as the atman, which is seen to be the self within the body. As in dualism, the mind within the body, they are distinct; thus Hinduism forges an obvious link to the strengths of dualism. In Christianity however, the belief in a physical resurrection is maintained, thus such ideas are not in keeping with those of dualism which profess the survival of the disembodied self, essentially that the soul survives without the body. Instead, contrary to dualism Christianity puts forward a belief that instead of the physical body dying and the soul self-continuing, both die until God raises the physical body once again. Islam is a third world religion that does not support dualism. Muslims believe that when you die, both the soul and body remain in the grave, and wait for Allah’s judgement upon judgement day. This stage is known as ‘Barzakh’. Upon judgement day, Islam upholds that the soul departs from the body and ascends into paradise; while the body remains in the grave.

To conclude, it can be seen that in the words of H.D.Lewis “dualism is an enormously attractive and powerful theory”. Indeed, it appeals to our human nature in that it explains what we fail to understand nor explain otherwise; acting as a combination of Marx and Russell’s critiques of religion: an opiate of hope. However, simply because such an explanation exists, does not mean that it necessarily stands as a logically and philosophically sound theory; and this is demonstrated in how many philosophers actually reject Descartes’ ontology. The main weakness of Descartes’ argument is in the ambiguous idea of “causal interaction” when he has stated that the two substances of mind and body exist in such contrasting realms; yet interact with cause; it seems almost illogical and has since been scientifically proven wrong. However despite the flaws in the fine details and logistics of Cartesian Dualism, it could also be possible to say that there is simply no point in pursuing the concept; for human language is too confined to hold the answer anyway.

This is supported by Wittgenstein, who stated that each human activity had its own language: “the game”, and that if you are not within the game then the game’s language is meaningless to you. This is applicable to a study of dualism, as it could be suggested that humans are simply not yet in ‘the game’ or able to understand. Furthermore, Wittgenstein proposed that for all their implications of being separate entities; the ‘soul’ and ‘body’ are still grounded in the same situation as words; and it is instead our brain’s presumptuous perception that sees them as two different things. On the contrary, R.M Hare argues against such theories of Wittgenstein and the logical positivists. To counteract their theories that religious and supernatural talk (such as the existence of a soul) is meaningless unless you are in ‘the game’ or it is empirically qualified, Hare developed the theory of ‘bliks’. Hare says religious people have a religious blik. Once you accept the religious blik, you have a new way of looking at the world. Your frame of reference is radically altered, and with it, your evidentiary standards.

Suddenly all sorts of things that previously did not count as evidence for God begin to count. Your evidentiary filter becomes much more porous. The existence of God becomes so obvious that nothing can falsify it, thus saying that such talk of supernaturalism does, in fact, have significant meaning. Thus, it can be seen that simply because the clarification of argument that is required by the philosopher has not yet been found, nor may our man-made concept of language yet be able to cope; it does not mean that we should reject Descartes’ theory altogether. For, regardless of whether they possess a ‘blik’ or not, there is an element in Descartes’ work “I think therefore I am” that rings truer to the human mind than any other philosopher’s, something indisputable and identifiable, and thus worthy of upholding.