The Ontological Problem: Dualism

Investigates the nature of mental states, their underlying medium, and their relationship to the physical world.
Evaluates competing theories of mind based on explanatory power, predictive power, coherence, and simplicity.

Posits that conscious intelligence resides in a nonphysical, distinct substance that exists independently of the physical body.
Cartesian Dualism (René Descartes): Divides reality into extended matter (spatial) and thinking substance (nonspatial).
- Struggles to explain causal interaction between a nonspatial mind and physical matter without violating physical laws like the conservation of momentum.
Popular Dualism: Conceives a person as a "ghost in a machine," where the spiritual mind resides inside the physical head/brain and interacts via energy exchanges (related to $E = mc^2$ ).

Asserts that while no nonphysical substance exists beyond the physical brain, the brain possesses unique, nonphysical, irreducible properties.
Epiphenomenalism: Mental states emerge when brain complexity passes a threshold, but remain causally impotent byproducts of physical brain activity.
Interactionist Property Dualism: Emergent mental properties actively exert causal effects on the physical brain and behavior.
Elemental-Property Dualism: Treats mental properties as fundamental, irreducible properties of the universe alongside mass, length, duration, and electric charge.

Argument from Religion: Links substance dualism to traditional religious beliefs in an immortal soul.
Argument from Introspection: Observes that direct inner reflection reveals a flow of conscious thoughts and feelings rather than neural network activity.
Argument from Irreducibility: Claims complex human capacities—such as language, mathematical reasoning, sensory qualia, and intentionality—cannot be explained by physical systems.
Parapsychological Phenomena: Suggests phenomena like telepathy or telekinesis reflect superphysical mental properties.

Ockham's Razor: Favors materialism because it postulates a simpler framework (only physical matter) without sacrificing explanatory coverage.
Explanatory Impotence: Unlike neuroscience, dualism provides no detailed structure, mechanisms, or explanatory laws regarding mental operations and pathologies.
Neural Dependence: Reason, emotion, and consciousness are severely altered or impaired by physical brain trauma, alcohol, narcotics, and anesthetics, demonstrating direct dependence on neural activity.
Evolutionary History: Modern humans developed through a purely physical evolutionary process over 3 billion years, leaving no theoretical necessity or room for nonphysical substances.