What is the relationship between mind and matter?
Materialism holds that the mental is a product of the physical – the mind is what the brain does. By contrast, dualist accounts are consistent with our common sense notion that the mental is fundamentally different from the physical. How much does a thought weigh? a dualist might ask. In this post I will offer a materialist position that offers all the strengths of materialism as commonly understood, but with none of the shortfalls.
Scientific Arguments for Materialism
- Changes in the brain lead to changes in experience. Think brain injury, drugs and the classic lab story of the man who reported smelling burnt toast upon having his brain tickled by a neurologist.
- We can bend spoons with our minds. A mental desire to bend the spoon leads to a cascade of physical events that ultimately result in our desire being fulfilled.
- Changes in experience lead to changes in the brain. We are able to learn, remember, develop skills and be traumatized because this moment’s experiences and efforts produce changes in the brain, some short-lived and others long-lasting.
Experiential Argument for Dualism
The mental and physical are clearly different. What does love weigh? How can a physical entity feel? Even if we were to completely map out the brain state of a person experiencing love there would be something qualitatively different about the brain state and the feeling. Dualism is assumed whenever one posits the existence of souls, spirits, and so on.
Many materialists argue that the difference between the experience and brain state of love is a matter of perspective. Two things can be the same and different at once. For example, I am a person and a student. Both of these things are true, but they are not the same thing. Secondly, if mind and matter are fundamentally different how do they interact? How does the mass-less emotion of love give one’s heart a jolt? It’s a fundamental law of physics that matter can only be influenced by matter. Similarly, how could matter affect the non-material?
If mind and matter are fundamentally different, how do they interact?
Solving the Mind-Body Problem
Reconciling the interactive nature of mind and matter with the appearance of fundamental difference between the two begins by acknowledging that humans do not perceive the world in a comprehensive and objective fashion. Our perceptual systems are not infinitely broad and precise. There are things we cannot perceive, such as high-pitched dog whistles or the sonar signals of bats. Similarly, our perception isn’t so fine-grained that we can distinguish between any two stimuli (e.g., two shades of blue that differ in wavelength by a single nanometer). This second point is important for the Mind-Body Problem.
Our perception is categorical. We hallucinate sharp divisions between stimuli that we have no reason to believe are actually sharply distinguished. For example, the phonemes (i.e., speech sounds) /b/ and /p/ are very similar in terms of sound wave structure, differing only slightly along a continuous sound wave spectrum. Similar to orange and red being neighbours on the continuous colour spectrum, /b/ and /p/ are neighbours on the continuous sound spectrum. Yet, studies have shown that at level of experience, there isn’t a gradual perceptual transition from /b/ to /p/. When beginning to move from a /b/ sound toward a /p/ sound, the transition is gradual. A small alteration to the sound wave produces a small alteration in sound perception. However, as we move closer to the midpoint between the wavelengths of /b/ and /p/, smaller and smaller additional changes to the sound wave produce larger and larger perceptual differences. This becomes so extreme that we perceive a sharp boundary between /b/ and /p/, despite the gradual stepwise nature of the transition. Similar findings exist in other areas of perception. Thus, we don’t simply perceive light. We perceive discrete colours. And we don’t simply hear a continuous spectrum of musical sounds; we hear qualitatively different musical tones. Moreover, despite sound and light both existing as waves, we see light and hear sound (though if you want to see where this rule breaks down, look up synaesthesia).
Putting It All Together – Seeing What God Would See
Just as we hallucinate a sharp qualitative difference between /b/ and /p/, the same may be true of mind and matter. Our experience of mind and matter being qualitative different may be no more true than our experience of /b/ and /p/ being qualitatively different. Just as /b/ and /p/ can be described as existing on a continuous wave spectrum, something analogous may be true of mind and matter. If so, we would have a satisfying account of how the two can at once appear so different and yet still clearly share at least one plain of co-existence along which to interact.