The Knowledge ArgumentThere’s Something About Mary

There are things Mary doesn’t know…

Reminder: Office Hour Visits Tuesday, March 24: Caswell, Gerards,

Johnson, Livstrom, Moberg, Mohr.

3-5 PM. If you cannot make that time, please let me know when you can.

This article has been very influential “Someday there will be no more articles

written about the ‘Knowledge Argument’… That is beyond dispute.  What is less certain is, how much sooner that day will come than the heat death of the universe.” (Bill Lycan)

Why has it been so influential? Because one continually gets the sense that

earlier 20th C. theories of mind failed to capture something important: phenomenal consciousness or the qualitative aspects of experience.

‘Phenomenal consciousness’ = what it is like from your subjective point of view.

Big changes down under The “first wave” of Australian philosophers

(Smart, Armstrong) were materialists.

The “second wave” of Aussies are dualists or epiphenomenalists (Jackson, Chalmers).

David Chalmers (1966-) Chalmers famously

distinguished between the hard and easy problems of consciousness.

Question: How does he distinguish between these two types of problems?

“Easy” Puzzles of Consciousness • the ability to discriminate, categorize, and react to environmental stimuli

• the integration of information by a cognitive system

• the reportability of mental states

• the ability of a system to access its own internal states

• the focus of attention

• the deliberate control of behavior

• the difference between wakefulness and sleep

Why are these “easy”? Chalmers is aware that “easy” is a relative

term. He acknowledges that we are not even close to fully understanding these topics; he writes that they will take centuries to solve.

But they are “easy” in the sense that we know how to go about answering them: in terms of computational or neural mechanisms.

Chalmers on easy puzzles “All of them are straightforwardly vulnerable to explanation

in terms of computational or neural mechanisms. To explain access and reportability, for example, we need only specify the mechanism by which information about internal states is retrieved and made available for verbal report. To explain the integration of information, we need only exhibit mechanisms by which information is brought together and exploited by later processes… In each case, an appropriate cognitive or neurophysiological model can clearly do the explanatory work” (Chalmers, “Facing Up to the Problem of Consciousness”).

Hard problem? The hard problem is to explain the phenomenal character of

experience. One might ask: but why cannot we just provide a neural mechanism as with the other problems?

Response: because it remains mysterious how and why these physical processes are connected to the qualitative aspects if experience. When you explain ‘integration of information’ in terms of brain wiring, you are done; but this is not the case with qualia: you still have not explained why these brain firings are accompanied with such-and-such qualitative experiences, or any such experiences at all.

More on the hardness of the problem Perhaps the issue is not (at this point) entirely clear. In order

to understand why Chalmers thinks that phenomenal consciousness is a problem of a different order of magnitude of difficulty, we must carefully examine several philosophical arguments.

The Knowledge Argument (Jackson)The Modal Argument (Kripke)The Explanatory Gap (Levine)

These arguments will help us understand why some contemporary philosophers (the “Mysterians”) have come to believe that the problem of consciousness might be insoluble.

The ‘Knowledge Argument’ The article is entitled

“Epiphenomenal Qualia”. We know what ‘epiphenomenal’ means. But what does ‘qualia’ mean?

Quale/qualia (Def.): the subjective, experiential character – what it is like – to have a mental state.

What is the structure of the argument? Jackson says that many people have the

intuition that qualia are non-physical.

But he does not want to rest his case on purely intuitive grounds. He wants to provide a logical argument for his position.

So: What is the structure of this argument?

The structure of the argument Jackson provides a quick gloss:

“Nothing you can tell of a physical sort captures the smell of a rose, for instance. Therefore, Physicalism is false” (127).

Jackson claims that this argument is ‘clearly valid’. He maintains that he need only polemically argue against his opponents that the premise is intuitive.

But the argument is not clearly valid. (The word “physicalism” does not appear in the premise). What are the premises that could turn it into one?

The (reconstructed) argument If physicalism, then _________.

Hint: Jackson’s definition of physicalism (p. 127).

So: If physicalism is true, then all information is physical information.

The (reconstructed) argument P1: If physicalism is true, then all information is

physical information.

Grounds: Definition of physicalism.

P2: There is some information that is not physical.

Grounds: ?

C: Physicalism is false.

The (reconstructed) argument The argument now appears to be valid. But the

question becomes: is it sound?

Question: What reasons do we have for thinking that P2 is true?

This is where Jackson’s thought-experiments come into the picture…They attempt to buttress P2 by showing that we *all* have this intuition.

Fred and Mary Fred: Suppose that we know all the physical

information there is to know about Fred. But we still wouldn’t know what it is like to experience red 1 and red 2. So seeing red 1 or 2 is non-physical information.

Mary: Suppose that Mary knows all the physical information about color perception. But she still doesn’t know what is like to see red, until she leaves the room. So the phenomenal character of color perception is non-physical information.

Intuition pumps So these thought-experiments show that we would

all accept the intuition that there is information (namely, about phenomenal feels) that is not physical.

But if this is the case, then it logically follows that physicalism is false. Jackson has completed his project: he has shown that there are sound arguments against reductive materialism.

Objections?