Nagel’s Bat and the Explanatory Gap

1. Nagel’s Bat and the Explanatory Gap

2. Nagel’s bat: preliminaries • Phenomenal consciousness is what makes the mind-body problem hard • Materialist analyses leave out what it is like

3. Nagel’s bat: preliminaries • How do materialist analyses leave out what it is like?

4. Nagel’s bat: preliminaries Consider the type-identity theory: pain = c-fiber stimulation This leaves out what it’s like to feel pain. For I can imagine feeling pain without my c-fibers firing and vice versa. Or consider functionalism:

5. Nagel’s bat: preliminaries • Pain = whatever plays causal-role X (is produced by damage to the body and produces avoidance behavior, and… • This too leaves out what it’s like to feel pain, for something could play causal-role X without it feeling the way pain feels.

6. Nagel’s bat: the thread of the argument • What is it like to be a bat? Can there be a physical account of what it is like?

7. Nagel’s bat: the thread of the argument • Bats are alien: We can’t have bat experiences (e.g. echolocatory experiences), we can’t even imagine what such experiences are like.

8. Nagel’s bat: the thread of the argument • You think you can imagine it because you can imagine what its like to hang upside down, emit high-pitched shrieks in order to navigate, etc. • But this gets you only what it would be like for you to behave as a bat behaves. • The question is: What it is like for a bat to be a bat?

9. Nagel’s bat: the thread of the argument • Experiences are private. You can’t have my token experiences. Is this all that is being claimed? • No. These what-it-is-likenesses are mental types that different subjects can instantiate. • But they are subjective; they embody a point of view.

10. Nagel’s bat: the thread of the argument • Physical facts, by contrast, are objective—accessible from many points of view. • Thus the difficulty in seeing how the facts about what it’s like to be a bat could be physical. • The clash between the subjective and the objective.

11. Nagel’s bat:the thread of the argument • “…if the facts of experience-facts about what it is like for the experiencing organism-are accessible only from one point of view, then it is a mystery how the true character of experiences could be revealed in the physical operation of that organism. The latter is a domain of objective facts par excellence…” (p. 522)

12. Nagel’s bat:the thread of the argument • The problem from another angle: • Typical cases of theoretical reduction (the model for materialist analyses) proceed by excluding the phenomenological. • Heat = molecular motion

13. Nagel’s bat:the thread of the argument • Sensations play no role, except to fix the reference of the term for thing reduced. • Heat is whatever produces heat-sensations in us and that property is, objectively, the motion of molecules.

14. Nagel’s bat:the thread of the argument • But when it comes to reducing the sensations themselves, there is no excluding the phenomenological; there is no appearance/reality distinction with respect to the sensations: pains = feelings of pain.

15. Nagel’s bat: the conclusion • Does Nagel think that we can conclude that materialism is false? • No. It’s just that we have no conception of how it could be true.

16. The explanatory gap • Inspired by Nagel, some philosophers say that even if materialism is true, we will never understand or explain the mind in physical terms.

17. The explanatory gap • The focus for those who push versions of the thesis that there is an explanatory gap between the mental and the physical is phenomenal consciousness. • The intuition is this: No matter how much we learn about the structure of the brain, nothing that we learn will explain to us why we have these sorts of experiences.

18. The explanatory gap • Nothing will explain why we have these as opposed to completely different ones • Or these as opposed to none at all. • Spectrum inversion • Zombies • The connection between the physical and the phenomenal appears arbitrary.

19. The explanatory gap • Van Gulick’s reply: If the explanatory gap intuition is supposed to be generated by the simplicity of experiences--by their having no structure--then the intuition can be met. • Experiences do have structure. • Binary vs. unary hues • The affective dimension of phenomenal color.

20. The explanatory gap • At best, Van Gulick’s reply succeeds against the spectrum inversion justification for the explanatory gap. • But what about the zombie justification?