The mind, or ‘soul’ as it has come to be known to some, is classified as a ‘non-physical entity’ that is separate from the brain by Cartesian Dualists and linked to (but still different from) the brain by Property Dualists. These are perfectly reasonable ways to look at it as such concepts as qualia and privileged access and the fact that mental phenomena lack spatial features support these theories. While Materialists may doggedly reject Dualism, it can be noted that some of their arguments are by no means iron-clad, including their trump card, the ‘interaction problem’.
Also, Materialistic arguments fail to address and explain our mental experiences taking up no space, our privileged access and the phenomenology of our mental lives that cannot be explained by Materialism alone. A very important concept to consider in favour of Dualism is that the mental and the physical seem to have quite different and perhaps irreconcilable properties. Mental phenomena have a certain ‘raw feel’ to them, whereas physical events seem not to.
For example, explaining what the blueness of the sky looks like or what nice music sounds like could not be done easily as there are subjective aspects, also known as ‘qualia’, about them. There is something that it's like to feel pain, to see a familiar shade of blue and so on. There are qualia involved in these mental events and these qualia seem particularly difficult to reduce to anything physical, implying that there is something more than just a physical sensation.
After all, how could a lumpy, squishy mass of brain generate such complex mental phenomena as falling in love, or admiring an art masterpiece? Thomas Nagel first characterised the notion of qualia in his article ‘What is it like to be a bat? ’ and he argued that even if we knew everything there was to know from a third-person, scientific perspective about a bat's sonar system, we still wouldn't know what it is like to be a bat. As well as not being able to understand the subjective quality of being a bat, we are also unable to see into its mind and view its experience of being a bat.
Our mental experiences and consciousness appear to be completely internal and private from all eyes except our own. This can be applied to Nagle’s article on bats in the sense that even if we knew all the physical facts concerning what goes on inside a bat’s mind when it uses echolocation, we still wouldn’t know what the experience was like for the bat. He explored the privacy of consciousness in his paper ‘What is it like to be a bat? ’ and asked how we could know what it is like to experience the world from the point of view of another living being.
He concluded that however much one knew about a bat’s brain and body, it would be impossible to know what is like to be a bat. Similarly, our minds are completely private, it would seem, and inaccessible to others. Even if we were to wire someone’s nervous system to another person’s so that both brains received identical sensory stimulation, their mental experiences would remain concealed from each other. For example, take two people eating the exact same flavour of ice cream.
They’d both get the same aesthetic, olfactory and gustatory qualities but their experiences of it would be different, meaning that our minds would be something like a ‘psychological construct’, which means that a mind is believed to exist but is unable to be directly observed or sensed in any way. Similarly, our mental phenomena could also be considered as psychological constructs. A crucial property of all physical things is extension in space, which mental phenomena do not have.
How would a spatially-arranged matter (the brain) conspire to produce non-spatial mental states? It seems utterly inexplicable. Furthermore, if the mind were a physical thing, it would occupy a space of some kind, however small or weightless. This doesn’t seem to be the case though. Neuroscientists have dissected and examined many a brain and have never found anything that could be classified as a ‘mind’, meaning that the mind cannot be a physical thing. The same thing can apply to our mental experiences.
For example, at a music concert, the musicians would be playing their instruments, producing physical sound waves and physical processes in one’s eardrums, and these could easily be observed with the right scientific equipment, designed to measure such things. However, one’s experience of the music would be impossible to find as it would be unextended and undetectable. One would think that this was an obvious indicator that mental experiences were completely private, had no location and couldn’t be physical, though Materialists deny this through their strongest argument, the ‘interaction problem’.
In basic terms, the interaction problem states that Cartesian Dualism does not explain how the mind and body (the brain) interact with each other if the two are completely separate substances. Property Dualism counters this by suggesting that the mind is simply linked to the brain via it being a property of it, but still being different from it. Also, they insist that something non-physical like the mind couldn’t possibly cause a bunch of neurons to fire in order to do something, such as walk across a room, as there is no physical event which causes the firing.
This means that some physical energy is required to be generated against the physical laws of the universe. However, it might be possible for mind to influence the distribution of energy, without altering its quantity. Another possibility is to deny that the human body is a closed system as since the principle of conservation of energy applies only to closed systems, the objection becomes irrelevant. As for some of Materialism’s other points, Ockham’s’ Razor and the hope that science will ‘one day’ understand the mind completely are hardly reliable.
For one thing, Ockham’s Razor is very much dependent on what one’s idea of what ‘simpler’ is. Additionally, the mere chance that science will eventually be able to make sense of the complex workings of humans’ minds is an extremely flimsy argument as there are no guarantees that the day this happens will ever come. The ‘non-physical entity’ or ‘mind’ is separate from the brain according to Cartesian Dualists and linked to (but still different from) the brain according to Property Dualists.
Such concepts as qualia and privileged access and the fact that mental phenomena lack spatial features support these theories and while Materialists rebuff Dualism, some of their arguments aren’t reliable, such as Ockham’s Razor, the hope that science will one day understand the workings of the human mind and the biggest challenge to Dualism, the ‘interaction problem’. But the fact remains that however convincing the arguments for each side may be, the uncertainty surrounding the issue of the soul and the mind will remain for ages to come.