Motivations for Dualism

Substance Dualism is the belief that the human being is not just matter, subject to physical laws and interactions, but is comprised of two substances; the physical part, or the body which is subject to physical laws and has physical properties, and the non-physical part. This has been labelled in a variety of different ways, the most prominent in western society being either ‘the soul’ or ‘the mind’. There are many reasons as to why people have subscribed to this idea and I will attempt to describe and explain these motivations, as well as highlighting the plethora of problems associated with the supporting arguments, most of which buckle under the recent advances in neuroscience and the logic put forward by the opposing view of materialism; the idea that the ‘mind’ is a physical or a material thing, and that our conscious experience is nothing more than a series of mental states, subjective to the functioning of our brain and nervous system.

Many arguments in support of Dualism arise from various different religious texts, detailing that every human being was created by an omnipotent, omnipresent and omniscient being that designed each one of us with a physical and impermanent material body, whilst imbuing us with an immortal soul that will enjoy eternal life. The most basic of these arguments appeal to the authority of the scripture, usually with the premise, “because the scripture says so.” One of the many reasons why accepting this clause would be insufficient is that there are many statements made in these scriptures which we consider either metaphorical or just completely false, so why should we not extend this level of scrutiny to the idea of an immortal soul? Another premise that arises from this train of thought is, “if God exists, he wouldn’t create us just to live brief lives here on earth” or “there must be an afterlife, or what’s the point of it all?” Now the interesting problem with the age old ‘Why are we here?’ question is that, fundamentally, it doesn’t make sense. Just because something looks like a question, it doesn’t necessarily warrant an answer; e.g. “Why is purple?” There is no ‘why’ behind purple, it just exists. There does not have to be a specific reasoning behind the existence of the human race that fits neatly with our ideas of purpose and logic. To this end, there is no imperative reason why human beings must have an immortal soul, or indeed access to an afterlife.

Arguments for Dualism become stronger when we encounter Descartes, the 17th century French philosopher widely considered the ‘father of modern Dualism’. One of his best known arguments is his ‘Argument from Doubt’, which follows; “I can doubt that my body exists, but I cannot doubt that I myself exist. Therefore, I myself am entirely distinct from my body, and substance Dualism must be true.” A simple, yet effective parody argument was devised to demonstrate the problems with this, using the idea of Superman and Lois Lane that follows; Lois Lane can doubt that Clark Kent is Superman. She cannot doubt that Superman is Superman, therefore Clark Kent isn’t Superman. Here we can see how this reasonable sounding logic can in fact lead us to the wrong conclusion.

There is also Descartes’ Conceivability Argument which states; “We can clearly and distinctly conceive of our minds being just as they are even though our bodies no longer exist. If we can clearly and distinctly conceive of something then it is possible, so it is possible for our minds to be just as they are even though our bodies no longer exist, so our minds must be distinct from our bodies, therefore they must be non-physical and substance dualism is true.” There are a few problems with this argument, the most prominent being the idea that if we can conceive of something then it is

possible; it is possible to imagine a ball floating across a room and then slowly passing through a brick wall, but in no way will this ever be possible. Furthermore, viewing this argument as a materialist, there is a problem with the first premise of both of Descartes’ arguments listed above. A materialist considers the mind as just a mental state or consciousness created by the brain. This makes it impossible to accept the idea of conceiving of a separation between the two; it is possible to imagine consciousness without seeming to ‘see’ a body, or an outer-body experience, but to actually experience consciousness without any input from senses or the body is an experience we simulate by drawing on instances we are familiar with, such as closing our eyes, the very idea of which involves having a body with eyes to close and a brain to register it. This is not the same as your body not existing, and so I do not think it seems possible to imagine this. A materialist would also say that the mind is intrinsically linked to the brain in such a way that ‘I’ is synonymous with the body; therefore the premise would read, ‘It is possible that my body should not really exist while [my body] exist[s]’ which is also a state impossible to conceive of.

Another one of his well known points is the ‘Argument from Divisibility’, in which it is proposed that “The body is divisible (it comes apart), and this is true of all physical things. The mind, however, is indivisible, and so the mind has a property that the body lacks; minds must be distinct from bodies and so must be non-physical, therefore substance Dualism is true.” This must have seemed an imposing argument until the dawn of neuroscience and brain surgery, which demonstrated that the brain can be surgically halved, with evident ‘split consciousness’ in which different limbs perform different tasks and do not coordinate with each other (Wolman, Nature 2012). Even before this, cases of amnesia have been documented; this loss of memory surely constitutes the loss of part of the ‘mind’. There is even a problem with the first statement made; it is true that if you divide a rock, you get two rocks, but this basic disability idea doesn’t extend to complex structures. If you split a table in half, you don’t get two tables.

A more challenging argument supporting Dualism is the ‘Argument from Introspection’ that follows; “If our mental states were physical, they’d be constituted by neural activity in our heads. When we introspect, it doesn’t seem to us as if our mental states are constituted by neural activity in our heads, therefore our mental states are not constituted by neural activity in our heads and are not physical. This means they must be non-physical, and so substance dualism is true.” This is more elegantly explained by Churchland in Matter and Consciousness, stating “When you centre your attention on the contents of your consciousness, you do not clearly apprehend a neural network pulsing with electrochemical activity: you apprehend a flux of thoughts, sensations, desires, and emotions. It seems that mental states and properties, as revealed in introspection, could hardly be more different from physical states and properties if they tried. The verdict of introspection, therefore, seems strongly on the side of some form of dualism." To counter this, we must remember how this argument assumes that introspection, or inner observation, must reveal things in an honest and non-simplistic way. We should not accept this premise, when none of our other senses and means of observation follow this rule; when we look at a puddle, we don’t see millions of bonded molecules of water. Why then, when introspecting, should the infinitely complex neural activity of our brains be immediately apparent?

There are many arguments for substance dualism, some of which appear very convincing at first. There is no doubt that some of these would still be contested today, were it not for the significant advances in medicine and technology that occurred since they were originally posited.

Today, however, the various arguments supporting the idea of a non-physical ‘soul’ are not strong, and do not bear up under heavy scrutiny.

Bibliography

1. The Split Brain: A tale of two halves, by David Wolman, Nature journal, 483, 260-263 (15 March 2012)

2. Matter and Consciousness, Paul M. Churchland

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