The conceivability argument says that if you can conceive of something it is metaphysically possible. Cartesian dualism suggests that the mind and the brain are two different things, and that the mind can exist independent of the brain. I will show through my own arguments that the argument for an immaterial mind was improperly conceived, and thus by its own terms, metaphysically improbable.
Let’s assume that Descartes is right and the mind and body are not causally dependent, what is he saying. Substance Dualism is a position that states that mind and the body are radically different things. Dualism is the idea that in a particular domain there are two fundamental kinds of things, or principles (good vs. evil in the context of theological dualism). Descartes believes that there are then two types of properties, properties of the mind, and properties of the physical. Inspecting the relationship between the mind and the body raises many questions. For example, If the mind can exist independent of the brain, and each mind is unique, does the creation and formation of the mind depend on the brain? A person suffering from dementia loses her capacities; her capacity to think, her capacity to remember, and to form long-term memories, her capacity to reason, her capacity to think critically. Even people with more advanced cases of dementia still have days where they ‘snap out of it’. The dust settles for a moment and like a spectre, they assume their former identity.
In the future we will be able to prevent dementia, and treat dementia. We will in the future be able to regrow neurons and lost cells, re-form damaged areas of the brain, and give people back the mental functions they have lost. As it stands now, though, we are not capable of those things. We have medications to slow the progress of dementia, and some treatments, but the most promising studies and experiments and theories are not yet near completion. If you suffered for years with complex dementia and died before science could ‘turn back the clock’, what would happen to your immaterial mind?
If the immaterial mind is effected by changes in the material brain, and the experiences of the individual, could it return to its original state (prior to dementia)? If the brain shapes the mind, and the mind depends on the development of the brain through an individuals lifetime, wouldn’t the immaterial mind of the dementia patient continue to exist after death as it had near the end of the individuals life? Would it exist immaterially as the mind of a late-stage dementia patient?
If there is an immaterial mind, why bother at all with a material body? If the immaterial mind can transcend the limitations of an afflicted physiology, why attend to a corporeal form in the first place? If the immaterial mind can survive unscathed by diseases like dementia, then what purpose does life as a biological organism provide?
The immaterial mind has to (conceptually) causally depend on the material body – for its formation and creation. The normal stages of development in an infant are of necessity to the development of the infant. If a child is deprived of social contact, it will not become a ‘person’; that is, it will not learn to speak, to walk, to reason, to identify language, to survive. It wouldn’t become what it would’ve become. The adolescent life of that child would be indistinct from its infant stages. The immaterial mind is affected by the biology clearly.
We might attempt to solve this problem by assuming that there exists a benevolent, omniscient, creator. That might solve the proximal problem described above, but it begs the question: why bother with a biological body? We cannot at present hope to answer this question – if it’s a question we’re capable of answering at all.
Could the immaterial mind of a dementia patient correct itself after death? Even if we assume it can, it still offers no hope to the dualist or the idea of an immaterial mind. It is a self defeating proposition. All the changes in our mind are products of both growth and decay. An infants brain imperfectly prunes the neurons. That imperfection shapes the child. We suffer damages to our brains throughout our life without ever knowing it. Those changes determine who we are. Forgetting we are determined by our brains, by our biology, and indirectly by our experiences, how could the immaterial mind identify which things needed to change and which things didn’t – if the process of growth is constrained and fostered by mechanisms similar to those in pathological processes. The immaterial mind theory necessitates biological determinism, and causal determinism.
The changes in our brains don’t ameliorate our consciousness, and so perhaps the immaterial mind could make similar changes too without ameliorating consciousness. But if the immaterial mind doesn’t causally depend on the biological brain for its creation and formation, wouldn’t it be blank if an infant died? Or rather wouldn’t the immaterial mind survive as an infant? Or is the immaterial mind a conscious being, unique to itself like the (notion/ theory of) brains of biological beings which produce conscious minds unique to the individual. Does the immaterial mind provide consciousness, or act upon consciousness? If it provides consciousness, then it is functionally indistinguishable from the material theory of consciousness. Because in both cases the mind of an infant at death is the mind of an infant, and the mind of a dementia patient at death is the mind of a dementia patient. Even if conceptually the interaction between the immaterial and material could go one way and not the other, we know that it can’t be limited on the material end – infants without social attention develop adult bodies in time but never adult minds. But the interaction isn’t necessarily limited to one direction (material -> immaterial). In fact, it’s necessarily unlimited; by its own terms the immaterial mind is responsible for the material consciousness, thus interacting with consciousness. If the immaterial mind is necessarily effected by changes in the material mind, then the immaterial mind interacts with the material as well.