“ This nonphysical mind is in systematic causal interaction with your body…the desires and decisions of your nonphysical mind cause your body to behave in purposeful ways.” (p8, 1988)
But here, we stumble upon one of the most profoundly mysterious concepts associated with dualism – how can it be possible for nonphysical mental phenomena to have a causal effect or influence on a physical, entirely spatial entity?
Property dualism
A weaker version of dualism, which contemporary philosophers find more acceptable, is that human beings are physical entities that have a special set of nonphysical properties that somehow ‘emerge’ form the brain. This position is known as ‘property dualism’. The ultimate difference between property and substance dualism is that the substance dualist proposes that the nonphysical mind is a distinct nonphysical entity, independent of the physical mind, whilst a property dualist says that the mind is dependent on the brain’s function to exist, and the mind is a “nonphysical extrusion of the physical brain” (O’Brien, 2003). Such properties include the property of experiencing X, desiring Y, the sensation of touching Z and so on. These properties are said to be nonphysical because of their inability to be reduced to, or explained in terms of scientific knowledge.
Materialsm (or monism)
At the other end of the scale, the materialist attempts to explain everything in terms of physical objects. When we experience a thought or an emotion, the materialist reduces the experience to nothing more than electrical impulses in the brain, or chemical reactions in other parts of the body (Thompson, 1995).
Objection one – causal efficacy, or causal interaction
One of the most serious problems dualism implicitly raises is that of explaining how an interaction between the immaterial mind and physical body is legitimately possible? In other words, how do our nonphysical minds have an effect on the physical world, and shape our behaviour?
According to Warburton (1998), Descartes was aware of this explanatory difficulty and even went as far as to identify a site in the brain, the pineal gland, where he suspected mind – body interactions occurred. But locating where it occurs does not solve the mystery of how something that is nonphysical can bring about changes in the physical world. Dualism’s objections are often supported by laws of physics and the impossibilities of dualist beliefs are consequential to a lack of plausible physical explanation. One particular objection, however, is defended by nothing more than an obvious irrationality. Dennett (1991) discusses the simple, analogous incoherence of the nature of the cartoon figure, ‘Casper the Friendly Ghost’. How is it possible for Casper to both glide through walls (as if nonphysical) and simultaneously bump into things and move them around? (It would appear that anything that can move a physical thing, must itself be physical). Thus,
“How can mind stuff both elude all physical measurement and control the body?” (Dennett, p.35, 1991)
Dualism aims to overcome the objection
Dennett discusses the prospect of mind stuff being a special kind of matter, as a possible defense for the objection to dualism. But this explanation only resulted in the fraudulent encasing of a strange gooey substance known as ‘ectoplasm’ in a jar, which was supposedly the basic material of the spiritual world.
Dualism again endeavours to defend itself with a view that whilst physical events in the world give rise to nonphysical events, the nonphysical events have no impact on the physical world. This view is known as epiphenomenalism. Gregory (1998) discusses mental phenomena as accompanying and perhaps being causally dependent on physical events, but not having the capacity themselves to influence, or make any causal intrusion into the physical world. Nevertheless, it remains a difficult task to fathom something physical (brain) causing something nonphysical (a thought, sensation or emotion). Here, O’Brien (2003) claims that epiphenomenalism also runs into the problem of the evolution of minds. Such that, if we accept that mental phenomena have no causal effects on the physical world, then it follows that minds do not posses any survival techniques. Hence, how did they possibly evolve?
The mystery of causal efficacy, accompanied by that of mind-evolution cannot therefore be dispelled. Subsequently, it makes sense for one to adopt a materialist position (there is only one sort of substance – physical) rather than a dualist position (there are two kinds of substances – physical and nonphysical), since materialism appears to raise fewer difficulties.
Objection two – neural dependence of mental phenomena
We now stumble upon the second most significant objection that tends to confirm a materialist view of the mind-body problem; the neural dependence of mental phenomena. This astonishing argument of neural dependence of mental phenomena presents itself as a strong one. The substance dualist’s belief that the mind and body are
- subject to completely different principles of operation, and
- are independent and mutually exclusive (Gregory, 1998),
prompts this objection, which in fact comes close to invalidating the substance dualist position entirely. Let us imagine that there truly does exist an entity, separate from the brain, in which such things as consciousness and thought processing occurs. This entity is only dependent on the brain to feed it sensory experiences and execute chosen actions. If this were the case, then
“…one would expect reason, emotion and consciousness to be relatively invulnerable to direct control or pathology by manipulation or damage to the brain.” (Churchland, p.20, 1998)
Churchland discusses the incoherence of this claim, since the opposite is in fact true. Alcohol, narcotics or senile degeneration of nerve tissue can damage, impair or possibly destroy one’s ability to engage in coherent, rational thought. We know of countless forms of chemical drugs that affect emotion, such as anti-depressants that cause changes in one’s behaviour once the drugs circulate through the brain. Furthermore,
“the vulnerability of consciousness to the anaesthetics, to caffeine, and to something as simple as a blow on the head shows its very close dependence on neural activity in the brain.” (Churchland, p20, 1998)
According to Thompson (1995), if electrical shocks are applied to the brain, the recipient’s personality can be affected. Similarly, a patient suffering from brain damage will never have their same character. In some sever cases, he or she may not appear to be a person at all, but merely a living thing with no sign of normal mind attributions. Each of these connections between the mind and body make perfect sense if it were such that consciousness, thought, and emotion were all functions of the material brain itself. But for the substance dualist, this scientific evidence causes a worry. Suddenly the dualist theory, that consciousness, thought, and emotion occur in places entirely different, lacks coherence and logic.
Conclusion
It follows then, from these two primary objections and dualism’s inability to overcome these objections, that the mind will forever be beyond the reach of science. Since we are presently unable to delve into the science of the mind and crack the code to the mystery of the mind-body problem, dualism has thus built a barrier around itself; inhibiting us from further investigating the theory. Dualism is most commonly dismissed as a position, not necessarily because it can be convincingly objected against, but because, due to its unexplainable nature, it is a form of surrendering. In the words of Dennett (1991),
“…dualism wallows in mystery…” (p. 37).
Gregory (1998) refers to the philosopher Bertrand Russell (1872-1970) whose dualist position lasted just so long as he refused to construct the mental world out of physical components. Gregory (1998) also makes reference to the Dutch philosopher and monist, Benedict Spinoza (1632-1677) who claims that the problem of causal interaction vanishes if we take a monist position. He states that there are not two disparate items; that the mind and body are the one physical thing, and one thing cannot interact with itself. The interaction of the physical – nonphysical boundary is difficult to comprehend, and thus dualism cannot overcome the objection.
The second objection, regarding neural dependence, whilst it is not applicable to property dualism, profoundly criticises substance dualism and can never be overcome convincingly. We now find ourselves unable to defend the two most significant objections to dualism. In order to now progress in dispelling the mystery surrounding the mind–body problem, we must make a methodological decision to embrace materialism in an attempt to explain the mind, and its relationship with the body (O’Brien, 2003).
The mind is a fascinating mystery; something that we are most intimately related to, yet cannot explain plausibly. Whilst cognitive science and neuroscience is constantly solving the puzzle, there is still much to discover, and the future is exciting.
Reference List
Churchland, P.M. (1988) Matter and Consciousness, Chp.2 “The Ontological problem (the mind-body problem)” Cambridge, MA: MIT Press.
Dennett, D.C. (1991) Consciousness Explained Chp.2 “Explaining Consciousness” Boston: Little, Brown.
Gregory, R.L. (1998) The Oxford Companion to the Mind (The classic guide to the mind and its mysteries) Oxford: Oxford University Press
O’Brien, G (2003) Philosophy I Lecture Notes, Lectures 1 and 2 University of Adelaide
Thompson, M. (1995) Chp.3 “Mind and Body” Teach Yourself Philosophy UK, London: Hodder Headline Plc.
Warburton, N. (1998) Chp.3 “René Decartes, Meditation” Philosophy: The Classics London: Routledge
