A handful of arguments for physicalism

Simplicity

1. (Premise) If a simpler theory can explain the same data as a more complex one, the simpler is more likely true.
2. (Premise) Physicalism can explain the same data as dualism can.
3. (Premise) Physicalism is simpler than dualism.
4. Therefore, probably, physicalism is true.

Closure

1. (Premise) If an entirely physical event has an immediate cause, then the cause is entirely physical.
2. (Premise) If dualism holds, then some entirely physical event is caused by something not entirely physical.
3. Therefore, if dualism is not true.

Successes of neuroscience

Version 1

1. (Premise) The presuppositions of a highly successful science are likely to be true.
2. (Premise) Physicalism is a presupposition of neuroscience.
3. (Premise) Neuroscience is a highly successful science.
4. Therefore, physicalism is likely to be true.

Version 2

1. (Premise) When a theory makes a very surprising prediction, and the very surprising prediction comes true, then all other things being equal the theory more likely than alternatives that do not make that prediction.

2. (Premise) Physicalism makes the prediction that neuroscience will explain many phenomena.

3. (Premise) Dualism does not make the prediction that neuroscience will explain many phenomena.

4. (Premise) The prediction that neuroscience will explain many phenomena is surprising.

5. Therefore, all other things being equal, physicalism is more likely than dualism.

Robots

1. (Premise) If it is logically possible for a mind and its contents to be entirely constituted by the physical, human minds are constituted by the physical.
2. (Premise) It is logically possible for a robot to be conscious.
3. (Premise) If a robot had a mind, that mind and its contents would be entirely constituted by the physical.
4. Therefore, it is logically possible for a mind and its contents to be entirely constituted by the physical. (By 2 and 3)
5. Therefore, physicalism is true. (By 1, 4 and the definition of physicalism)

Behaviorism

Talk about mental phenomena is shorthand for talk about actual and potential patterns of behavior (quite likely multi-tracked).

Objection: There is no non-circular list of actual and potential behavior conditions that are necessary and sufficient for a mental state.

Identity theory

Each type of mental state is identical with some type of physical state within the central nervous system.

Considerations in favor:

• Our apparent physicality.
• Our mental activity exists for evolutionary reasons; mental activity that exists for evolutionary reasons has a neural grounding.
• Neural dependence and simplicity.
• Prediction: Neuroscience will be successful. This prediction is borne out.

Eliminative materialism

Considerations in favor:

• Lack of success of folk psychology.
• Lack of success in early versions of other scientific theories.
• Other theories are not as good

Considerations against:

• Introspection
• Self-defeat
• Exaggeration

Functionalism

Defining features of mental states are the causal relations to (1) environmental effects, (2) other mental states, and (3) bodily behavior.

Considerations in favor:

• Aliens and functional isomorphism
• Gradual replacement

Considerations against:

• Inverted spectrum (but qualitative character may differ without the state differing)
• Qualia (cf. Searle)