Epiphenomenal Qualia [notes on cognitive science]

05May09

In this paper by Frank Jackson, he introduces himself as a ‘qualia freak’. He argues that certain sensations and experiences cannot be accounted by a physicalist approach. A physicalist approach only considers physical information to be the “correct” kind of information, yet he argues that there are things that cannot be described just in terms of physical information, such as the smell of a rose, seeing the sky, feeling pain, etc; therefore physicalism is false. He acknowledges that this argument has little polemic validity. He tries to fix that by elaborating on what he calls “the knowledge argument”.

In the first section of his paper the explores the knowledge argument for qualia. Imagine Fred, a person with the highest ability to discern colors in the world. He is able to take a group of red, ripe tomatoes and sort them into two groups according to fine distinctions in their color which the rest of us are unable to differenciate. Moreover, if you blindfold him and shuffle up the tomatoes, he will be able to sort them again in the same fashion. Where us just see ‘red’, he can see ‘red1’ and ‘red2’. These aren’t just shades of red. To him, they are as distinct and contrasting as yellow and blue. When his retina is examined, scientist find cells capable of distinguishing ‘red2’ and ‘red2’ with the same precision as yellow and blue. Now, no amount of physical information about Fred would let us know what it is like to see ‘red1’ and ‘red2’. We can know all the physical information about Fred’s body and still not know everything about him. Jackson points out with this that physicalism always leaves something out.

Perhaps his most famous example is Mary. She’s a brilliant scientist that is forced to study color from a black and white room via a black and white television monitor. She specialises in the neuroscience of colour, and knows all there is to know about the physical information required for a human to perceive a certain wavelength of light and utter things like ‘blue’ or ‘yellow’. Now if we release her from her monochrome prison, will she learn anything new about colour? She will indeed, but since she knew all there was to know about colour from a physical point of view, yet her information is incomplete. (does she know the reaction that the colour will create upon her?). The knowledge view shows therefore that one can have all the physical information there is to be had about mental phenomena without having all the information.

The second part of the paper deals with the Modal Argument. He explains that no amount of physical information about someone else logically entails that he or she is conscious or feels anything at all. It is possible therefore to have agents that behave in exactly the same way as us but have no conscious mental life at all. What do they lack that we have? It cannot be anything physical (ex hypothesi) since they are equal to us in all physical aspects. Therefore there must be more to us than the purely physical.

The third part deals with the “what it is to be like” argument of Nagel. It states that we cannot possibly know what it is like to be a bat because no amount of physical information can tell us. The difference between this and the knowledge argument is that we’re not trying to find what it is like to be Fred, but that there was an aspect of his experience that remains unknown to us. Nagel talks about knowing what an unknown experience is like in terms of familiar ones. The problem with bats is that they are too unlike us. But this doesn’t reject physicalism, since it does not make any assumptions about the imaginative powers of human beings. If physicalism were true, we wouldn’t need any extra information or feats of imagination, we would have all the information already. This is not the case, however.

The fourth part deals with the problems that Epiphenomenalism entails. He argues that there is no problem in qualia having a causal powers over the physical world. He exposes three traditional reasons for this, and he argues that they have no effect whatsoever:

  1. Anything can fail to cause anything, no matter how often B follows A, there is always an over-arching theory that can overrule A’s causation powers over B.
  2. According to Evolution, traits that evolve over time are conductive to physical survival. If qualia evolved, then qualia must favour survival. But they couldn’t have evolved if they did nothing to the physical world. However, the only thing that follows from Darwin’s theory of Evolution is that any trait must have evolved to be either conductive to survival or a by-product of another conductive trait. Therefore, we can see qualia as by-products of traits conductive to survival.
  3. We come to know about other minds from behaviour. We can only expect someone else to have qualia if we regard the latter as the outcome of behaviour. We can however go back from effect to cause and consider another effect that the cause might have had. Now an epiphenomenalist states that qualia are effects of what goes on in the brain. They cause nothing physical but they are caused by something physical. So an Epiphenomenalist can go from the behaviours of others to their qualia by going back to the cause of the behaviour in the brain and out again to the qualia.

He concludes that while epiphenomenal qualia might indeed exist, they do and explain nothing. Furthermore, we cannot understand the how and the why of them because doing so is not necessary for survival. Physicalists argue that we’re part of nature, and thus we’re as nature left us after evolution. We understand as much as we do and it is reasonable to conceive things that fall beyond our understanding. Perhaps qualia is one of them.

from “Epiphenomenal Qualia” by Frank Jackson

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