Thoughts cannot be reduced to chemical reactions in the brain. To say otherwise is to greatly undermine the multifaceted nature of cognition and consciousness. Let’s take terms like “thoughts,” “consciousness,” and “mind” for example. To a substance dualist like me, who believes the mind is a metaphysical substance just as real as the material brain, thoughts are necessarily correlated to consciousness. They’re considered inseparable from the experience of being conscious. And the mind is the “organ” or substance responsible for consciousness.
With that said, there are some philosophy of mind professors/students who hold to an epiphenomenal view of consciousness, which is a form of property dualism. That means that although thoughts or mental states are directly caused by physical events in the brain, they themselves cannot have any causal effects. The analogy frequently used is an ocean wave. While the fluid transfer of energy through water molecules affects the foamy top of the wave’s crest, the foam does not have any causal powers over the wave that caused it. So foam is considered epiphenomenal. It’s a byproduct. Nothing more. The same goes for the brain-thought relationship, supposedly. According to this perspective, the brain is purely physical but the thoughts (or consciousness) that emanate from it are non-physical. Mental states are nothing more than a byproduct of physical processes.
From the perspective of strict physicalists, however, epiphenomenalism is superfluous. Thoughts do nothing. So why ascribe them mental properties? To them, thoughts are reducible to the physical organ of the brain, described by brain chemistry and neuroscience. One might be tempted to believe that terms like “thoughts,” “consciousness,” and “mind” are useful fictions. But that would be a mistake. Allegedly, the mind is a concept that refers to the physical process occurring in the brain. All mental phenomena are ultimately reduced to physical phenomena. So what is wrong with this reductionist view of the mind? And what is right about the substance dualist view?
One example from neuroscience will suffice to answer both questions. Jeffrey Schwartz, a psychiatrist specializing in Obsessive-Compulsive Disorder (OCD), and a proponent of substance dualism, has demonstrated using brain scans that the mind can influence/affect the brain in conditions like OCD. Patients, who showed abnormal patterns of brain activity on brain images correlated to dysfunctional mental states, experienced considerable relief when they engaged in a therapeutic treatment he calls the “Four Rs”—Relabeling, Reattributing, Refocusing, and Revaluing.[1] These patients used their conscious will to “relabel,” “reattribute,” “refocus,” and “revalue” intrusive thoughts, effectively changing brain activity through (literal) “mental force.” That is, this specialized approach of “self-directed neuroplasticity”[2] enabled them to change their biochemistry that was causing the OCD symptoms.
Therefore, the physicalist view, as well as the property dualist view, are flawed because they hold that causal powers only flow in one direction, from brain to mind, and not the other way around.[3] So no amount of mental effort should influence/affect brain activity. But Schwartz shows otherwise. Neuroplasticity—“the brain’s ability to create and reorganize neural connections”[4]—conclusively demonstrates that the mind is not a concept but a substance that has causal powers to crack the “brain lock”[5] of intrusive thinking.
[1] Jeffrey M. Schwartz and Sharon Begley, The Mind and the Brain: Neuroplasticity and the Power of Mental Force (New York, NY: HarperCollins, 2002), 79-95.
[2] Sandy Cohen, UCLA Health, “Training the Brain to Reconsider Troubling Thoughts Can Ease Mental Health Challenges,” May 9, 2023, https://www.uclahealth.org/news/article/training-brain-reconsider-troubling-thoughts-can-ease-mental (accessed December 5, 2024).
[3] The physicalist view also suffers from determinism. If all is physical, then all is determined. And if all is determined, then there’s no free will. But, according to Schwartz, quantum mechanics eradicates any semblance of determinism: “For quantum physics describes a world in which human consciousness is intimately tied into the causal structure of nature, a world purged of determinism.” Schwartz and Begley, 277.
[4] Cohen, “Training the Brain.”
[5] Schwartz and Begley, “Brain Lock,” 54.