Mind-Body Problem: Part 3
1 Physicalism
Human beings are entirely physical.
1.1 Arguments for Physicalism
- Occam’s Razor
- The interaction problem
1.2 Argument from Occam’s Razor
- Occam’s Razor
- Named after William of Occam (1290–1349). When two or more hypotheses/theories have equal explanatory power, we should choose the one that postulates the fewest entities.
Application: If consciousness can be explained in physicalist terms, then any reference to the mind/soul is superfluous.
From Jeffrey Olen:
Some people who have never seen a watch find one alongside a road. They pick it up and examine it, noticing that the second hand makes a regular sweep around the watch’s face. After some discussion, they conclude that the watch is run by a gremlin inside. They removed the back of the watch but cannot find the gremlin. After further discussion, they decide that it must be invisible. They also decide that it makes the hands go by running along the gears inside the watch. They replace the watch’s back and take it home. The next day the watch stops. Someone suggests that the gremlin is dead. Someone else suggests that it’s probably sleeping. They shake the watch to awaken the gremlin, but the watch remains stopped. Someone finally turns the stem. The second hand begins to move. The person who said that the gremlin was asleep smiles triumphantly. The winding has awakened it. For a long time the people hold the gremlin hypothesis, but finally an innovative citizen puts forth the hypothesis that the watch can work without a gremlin. He dismantles the watch and explains the movements of the inner parts. His fellows complain that he has left out the really important aspect, the gremlin. “Of course,” they agree, “the winding contributes to the turning of the gears. But only because it wakes up the gremlin, which then resumes its running.” But gradually the suggestion of the innovative citizen converts a number of others to his position. The gremlin is not vital to run the watch. Nevertheless, they are reluctant to reject the gremlin altogether. So they compromise and conclude that there is a gremlin inside, but he is not needed to run the watch. But the man who figured out that the watch worked without the intervention of a gremlin is dissatisfied. If we do not need the gremlin to explain how the watch works, why continue to believe that it exists? Isn’t it simpler to say that it does not?
— Jeffery Olen (in Pojman 2006, 189)
1.3 Argument form Occam’s Razor
Dualist Response
Occam’s razor does not apply in this circumstance. Why? Because the arguments for dualism that we looked at last class show that mental states cannot be reduced to physical states. It does no good to propose a simpler theory if that theory is inadequate for explaining the relevant facts.
1.4 Argument from the Interaction Problem
- The Interaction Problem
- Interaction between the physical and nonphysical is mysterious at best, impossible at worst.
- Where do the interactions of the soul and body take place?
- How do the interactions occur?
- How can the idea of the mental causing the physical be reconciled with the principle of conservation of energy?
1.5 Dualist Replies to the Interaction Problem
1.5.1 Where do the interactions of the soul and body take place?
- We do not have to understand where the mind is located in order to say that it affects the brain in the brain.
1.5.2 How do the interactions occur?
- We have plenty of evidence that interaction occurs without knowing how it occurs.
- Why should we suppose that substances must be qualitatively similar before they can influence one another?
1.5.3 How can the idea of the mental causing the physical be reconciled with the principle of the conservation of energy?
- The principle only applies to a closed system. Dualists are often theists. If theism is true, then the physical universe is not closed but part of a larger system.
- Conservation principles are not ubiquitous in physics. For example, Robin Collins has argued that energy is not conserved in general relativity, in quantum theory, or in the universe taken as a whole. Why then, should we insist on it in mind-brain interaction? (See Robinson 2020, sec. 3.1.)
1.6 Physicalism Major Types
- Identity Theory (The Hardware View)
- Mental states are identical to brain states.
- Functionalism (The Software View)
- Mental events can be exhaustively described in terms of sensory inputs, behavioral outputs, and internal states.
- Eliminative Materialism
- A fuller understanding of neuroscience will eventually eliminate the need to discuss mental states altogether.
1.7 Identity Theory
Mental states are brain states. A mental state or process is really a physical state or process in the brain or central nervous system and neuroscience will eventually advance to the point that we will have a successful reduction of mental states to brain states.
- Light is just electromagnetic waves.
- Temperature is mean molecular kinetic energy.
- Lightning is a sudden large-scale discharge of electrons between clouds or between the atmosphere and the ground.
- Mental states are just brain stats.
1.7.1 Argument for Identity Theory
- If identity theory is true, it explains why what we do to the brain affects the mind. For example, brain damage can influence behavior and memories.
- Moreover, the mind appears to depend on the brain.
- If neuroscience eventually develops to the point that we can show a one-to-one correspondence of brain states to mental states, then Occam’s razor should lead us to favor a physicalist interpretation of the data—mental states are brain states.
1.7.2 Objections to Identity Theory
- Leibniz Law type arguments for dualism
- The problem of multiple realizability
1.7.3 Multiple Realizability
- Multiple Realizability
- The idea something (e.g., a mental event) can be realized in many different forms and structures.
- An analog watch can be powered by a battery or springs.
- The same computer software can run on different kinds of hardware.
Issue: Humans, Dogs, Martins, and many other creatures can feel pain despite having very different brains.
1.8 Functionalism
Mental events can be exhaustively described in terms of sensory inputs, behavioral outputs, and other internal states. Functionalists reject the identity theory because, in their view, mental states are multiple realizable—that is, mental events can be realized in many different forms and structures.
- Identity theory presents a “hardware view” of mind
- Functionalism presents a “software view” of mind
1.8.1 Argument for Functionalism
The other argument for physicalism
\(+\) the multiple realizability objection to identity theory.
1.8.2 Objection to Functionalism
Like other forms of physicalism, functionalism has difficulty accounting for qualia.
- Inverted spectrum objection (we discussed this last class, see Chalmers 1996, sec. 3.2)
- Absent qualia objection: I can imagine a scenario where something else, perhaps a robot, is functionally isomorphic to me yet has no subjective experiences.
- Intentionality objection
1.8.3 Intentionality Objection
- Intentionality (also called aboutness or ofness)
- the property of being of or about something else)
- mental states (e.g., beliefs and desires) are directed at or about objects or states of affairs other than themselves.
- physical stats are not directed at or about objects or states of affairs other than themselves.
Issue: It is entirely possible for two systems to be functionally isomorphic (to parallel each others’ input, output, and internal states) while only one of those systems has intentional states.
1.8.4 Crash Course Video with Searle’s Chinese Room Thought Experiment
1.9 Eliminative Materialism
Identity theorists hope neuroscience will lead to a reduction of mental states to brain states. Eliminative materialists reject reduction and argue that neuroscience will eliminate the need to talk about mental states altogether.
- We no longer refer to a fluid called caloric to explain heat. (For more, do a web search for The Caloric Theory of Heat)
- We no longer appeal to the sphere of the heavens to understand celestial motion.
- One day, we will no longer need mental states to explain human actions and psychology.