Our day-to-day interactions seem fairly effortless and straightforward: if we want something, we do it; if we feel hungry, our brain alerts us, causing us to look after our lack of food. With the advances of neuroscience and psychology, we can learn how the brain works and how it drives our behavior. Wincing after a painful blow or sweating when hot is now traced to the brain, which triggers a certain response depending on the situation. But while this answer is satisfactory for scientists, philosophers throughout the ages could not help but be skeptical, theorizing that perhaps there is another driving force, that maybe the brain is not entirely responsible for our actions. After all, how could abstract thoughts possibly cause physical outcomes? This philosophical question, known as the mind-body problem, has been tackled by tens of philosophers, whose theories have changed our way of approaching everyday behavior.
Before we can examine the positions taken by philosophers we must be able to establish some key terms that are integral to the discussion. The words ‘brain’ and ‘mind’ are used interchangeably, though the debate as to what each means has led to a distinction between the material, that is to say physical, and the immaterial, or non-physical. Where some see the brain as the command center wherein all decisions are made, others such as David Hume and William James proposed the bundle theory, stating the mind is completely immaterial, comprising a collection of applied concepts. James, a psychologist, also came up with the stream of consciousness, defining the mind as the constant coming and going of thoughts. Another view is that of the spirit, from the Latin spiritus for breath. Since Greece, many have believed in a non-physical entity within our bodies. The soul, in spiritual terms, is thought to be the cause of desire and every other feeling we encounter.
The first position usually thought of is dualism, specifically cartesian dualism, created by René Descartes. Descartes believed there were two realms: the material realm, where the body resided, and the immaterial realm, where the mind resided. Put together, a union is formed, and the mind, like a captain, steers the ship—the body. “Extension in length, breadth and depth, constitutes the nature of corporeal substance and thought constitutes the nature of thinking substance,”¹ wrote Descartes, defining the rational, non-spatial mind and the spatial body. There was a fatal flaw with Descartes’ logic, considering the mind takes up no space, yet it can interact with the body that does take up space. Another philosopher, Gilbert Ryles, refuted cartesian dualism, referring to it as the “ghost in the machine,” because he envisioned the system as a ghostly figure resting inside the body, controlling it as though it were a robot. Ted Honderich summed it up as follows: “Mental states and processes are to be construed as states and processes occurring in certain complex physical systems … not as states of some ghostly immaterial being.”² Descartes, who claimed the pineal gland acted as the mediator between the mind and body, said, “The soul has its principal seat in the little gland which exists in the middle of the brain.”³ This theory is known as interactionism, a theory concluding that causation can go back and forth, from mind to body, neither taking precedence over the other.
The idea of dualism never died. Nor will it. Several other ideas popped up after Descartes, albeit none were as elaborate or as well-developed as the famous Modern philosopher. Similar to Descartes’ union was Baruch de Spinoza’s dual aspect theory. According to this belief, God had endowed all of us as a single entity, but instead of existing in different realms, our mind and body coexist as a single system. Using God, other philosophers could get away with any explanation, seeing as an omnipotent deity could grant us everything, so the propositions following Spinoza were nearly identical. The solution stating that God set the mind and body like a mechanical clock is known as occasionalism, advocated by Nicolas Malebranche. By comparing the process to a clock, Malebranche was able to explain that when both hands were aligned, a single outcome, caused by God, would occur. Parallelism has the same premise, minus the help of God. Parallelism said that it is purely a coincidence that the mind and body react at the same time. To use a cliché, if you were to touch a stove, the physical event, touching the stove, just happened to coincide with a mental event, the sensation of pain.
Unfortunately, as the philosophy of the mind attracted more attention, so too did it grow more complex, giving rise to more diverse, mind-boggling theories. The advent of classical conditioning, or behaviorism, in psychology, influenced philosophers in an interesting way, resulting in the view of philosophical behaviorism. This theory was soon abandoned and replaced with a newer theory, functionalism. Functionalists, as opposed to the physicalists, whom we shall cover presently, did not label feelings based on brain activity but the specific outcome of a certain event. Think back to functions in math class if you can. Every input has a single output. Coming back to the feeling of pain, let us propose pain is identified with wincing and a loud cry of dis-ease. You touch the hot stove, which elicits a wince and a cry; therefore, you have experience pain; you are punched, which elicits a wince and a cry; once more, that is pain; let us say, then, that you fall, causing you to cry but not wince. Is it still pain? According to functionalists, no. Certain feelings are linked to specific reactions, functional reactions. Nervousness is linked with the function of tremors and excitability. Were one to fulfill those specific functions, one would be nervous.
Before covering the physicalists and eliminativists, we shall briefly discuss epiphenomenalism, currently the most accepted variation of dualism. Recall interactionism, which said that physical and mental events are equal, each exerting the same power over the other. Epiphenomenalists, on the other hand, believe it is a one-way exchange, where only physical events can affect mental ones and not the other way around; however, epiphenomenalists also states that physical events do not always cause mental events. Touching the stove, feeling harm, your hand alerts your brain, causing you take your hand off the surface for protection. In this scenario it is the physical event that initiates the mental one. Should you find yourself leaning toward epiphenomenalism, be aware of epiphobia, the humorous fear of becoming an epiphenomenalist.
Lastly are physicalism and eliminativism. The former is the accepted scientific theory, no philosophy needed, as it is based on the latest findings in neuroscience. This time, when you touch the stove a final time, the C-fibers in your nervous system send a pulse to your brain, whereupon more neurotransmitters are fired, resulting in the movement of muscle fibers, ordering your hand to move, ultimately. Boring. Physicalists also make no distinction between mind and brain, identifying the former with the latter. If physicalism does not suit your fancy and is not stripped bare enough, then perhaps eliminativism, an extreme form of physicalism, will be more fitting. Referred to also as material eliminativism, this mode of thought claims everything in this universe is physical, spatial, and existing in matter. Further, they eschew any folk psychology, rejecting anything that has to do with concepts like ‘fear,’ ‘desire,’ and ‘hope,’ among others.
When it was up to Arthur Schopenhauer to address the mind-body problem, he refused to do so, saying it was impossible for humans to solve it. Perhaps he was right; for while we may never be able to study the mind, consciousness, or behavior either objectively or properly, we may still theorize freely, no matter how wrong or how outlandish our theories. It is a wonder we are evening thinking about our thinking in the first place. A small step toward the true answer, maybe? So while our philosophizing might as well be in vain, it can be done in the name of wisdom.
¹Beardsley, The European Philosophers from Descartes to Nietzsche, p. 88
²Honderich, The Oxford Companion to Philosophy, p. 579
³Beardsley, op. c., p. 93
For further reading:
The European Philosophers from Descartes to Nietzsche by Monroe Beardsley (1992)
501 Things You Should Have Learned About Philosophy by Alison Rattle (2012)
The Story of Philosophy by James Garvey and Jeremy Stangroom (2012)
1001 Ideas That Changed the Way We Think by Robert Arp (2013)
The Oxford Companion to Philosophy by Ted Honderich (1995)
The Encyclopedia of Philosophy Vol. V by Paul Edwards (1967)
Connections to the World by Arthur C. Danto (1997)