Philosophy 4610

1. Philosophy 4610 Philosophy of Mind Week 12: Qualia Friends and Foes

2. Qualia: The reality of a term • Last week, we considered Nagel’s argument that it is very difficult or impossible to explain conscious experience, or qualia, in physical terms. • Frank Jackson gives another argument to demonstrate that, because of qualia, physicalism is probably false. • Physicalist philosophers, like Dennett, have argued that pro-qualia arguments are grounded in a confusion: although there is consciousness, there is no such thing as qualia, and consciousness is wholly explainable in physical/functional terms.

3. Jackson and Mary • To show that physicalism is false, Jackson considers the case of Mary, a gifted neuroscientist who has spent her whole life locked inside a room in which everything is colored in shades of black, white, or grey

4. “Mary is a brilliant scientist who is, for whatever reason, forced to investigate the world from a black and white room via a black and white television monitor. She specializes in the neurophysiology of vision and acquires, let us suppose, all the physical information there is to obtain about what goes on when we see ripe tomatoes, or the sky, and use terms like ‘red’, ‘blue’, and so on. She discovers, for example, just which wave-length combinations from the sky stimulate the retina, and exactly how this produces via the central nervous system the contraction of the vocal chords and expulsion of air from the lungs that results in the uttering of the sentence ‘The sky is blue.’ (It can hardly be denied that it is in principle possible to obtain all this physical information from black and white television …)” (p. 275)

5. Mary the neuroscientist • Mary can read any fact that can be written down and can also watch demonstrations on a black-and-white television. • Over the course of years, she learns every physical fact about the brain and how it processes color • Yet she has never seen anything blue. She still does not know what it is like to see blue.

6. Mary and Physicalism • After her years of research, Mary knows every physical fact about neuroanatomy, color processing, wavelengths, etc. (Indeed, we can assume that she knows every physical fact there is). • Yet she still does not know what it is like to see blue – she only finds this out when she exits the room. • It follows that what it is like to see blue – the quale of blueness – is not physical and cannot be explained in terms of physical facts.

7. Jackson and Zombies • Another possibility that Jackson suggests – what he calls the “modal” argument – is the possibility of “zombies” or beings without qualia. • Zombies are physically and functionally identical to us, but have no conscious experience or qualia.

8. Zombies • If Zombies are conceivable, then it is possible to imagine a world in which all the physical and functional facts are the same, but there is no conscious experience. If that is conceivable, then conscious experience is independent of the physical and functional facts, and cannot be explained in terms of them. • Are zombies really conceivable?

9. Dennett against qualia • Dennett is a physicalist who thinks there is no “deep” problem with explaining consciousness in physical terms • He will argue that the whole concept of “qualia” is misguided and should be replaced with a description in terms of physical and fucntional properties.

10. Traditional assumptions about Qualia • Qualia are traditionally taken to have several defining properties: • Ineffable: Can’t describe them • Intrinsic: Don’t depend on any others • Private: Known only from 1st-person point of view • Immediately apprehensible: Known without judgment or reflection

11. Dennett, however, thinks that nothing has all of these properties. • When we see that qualia, so characterized, don’t exist, we’ll be able to replace the notion of qualia with straightforwardly physical/functional notions.

12. The Inverted Spectrum • The idea of the inverted spectrum, which goes back to Locke, is the idea of a person whose color-experience is systematically inverted. • The inverted spectrum is sometimes used as an argument for qualia, but Dennett will use it as an argument against.

13. The Inverted Spectrum • At first it seems as if the inverted spectrum case is realistic and conceivable. There could be someone whose color-experience is directly opposite to mine or yours: whenever you see something red, they have a “green” quale, and so forth. • But consider someone whose spectrum has been inverted from birth. What words will they use to describe the experiences they are having?

14. Even the inverted-spectrum person would behave exactly as we do. That is, he would call fire engines “red”, the sky “blue”, etc. • According to Dennett, there would be no functional or physical difference between us and the color-inverted person. • How can we even tell, then, that we are not suffering spectrum inversion?

15. Chase and Sanborn, the coffee-tasters • Chase and Sanborn have been tasting coffee for many years, but they both don’t like doing it anymore.

16. Chase and Sanborn • Chase thinks the taste of the coffee is just the same as always – he is getting the same quale – but he just doesn’t enjoy that taste, that quale, anymore. • Sanborn, by contrast, thinks the taste (the quale) itself has changed: where he used to get the taste of good coffee, now he’s getting another, different quale, one that he doesn’t enjoy as much

17. Chase and Sanborn • But can we really tell the difference between what Chase says and what Sanborn says? • If there really were qualia, then the difference between Chase and Sanborn would make sense. But Dennett argues that it does not: there is actually no meaningful difference between what Chase says and what Sanborn says.

18. Quining Qualia: Conclusions • If Dennett is right and it is impossible to tell the difference between Chase and Sanborn, then there is no need to postulate “qulia” to explain the taste-judgments we make. • There are just these judgments themselves, but we can explain these fully in terms of physical and functional facts that are perfectly accessible from a third-person, objective point of view. • Thus there is no special “hard” problem of explaining consciousness. It’s just a matter of time until we have a good physicalist explanation of how consciousness works.