Lecture 12 Notes

The Knowledge Argument

1. Mary knows all physical facts about color vision.
1. Suppose that Mary is a brilliant neuro-scientist who has learned everything that goes on in the brain when color vision occurs.  She knows all of the physical facts about color vision. 
   
2. Moreover, Mary has been colorblind since birth.  But, of course, she could still learn what happens in the brain when color vision occurs even if she doesn't see color.
2. Mary does not know all facts about color vision.
1. Demonstrated by Mary's learning when seeing red.
2. It seems that if Mary's colorblindness were corrected, she would learn something new about the color red when she saw it for the first time, namely, what it is like to see red.
3. Therefore, some facts about color vision are left out of the physical account
4. Therefore, some aspects of color vision (and other qualia) are non-physical.

The Knowledge Argument and Epiphenomenalism

1. Jackson thinks that his argument is good support for epiphenomenalism.
2. Why epiphenomenalism?
1. Jackson's argument concludes that there are non-physical aspects of color vision.
2. But there is causal closure in the physical world.  There is no evidence of gaps in neurological processing.  It seems like some gaps should occur if there are non-physical causal agents.
3. Therefore, the non-physical aspects of color vision are causally powerless.  This is ephiphenomenalism.
3. Apparent Problem with Epiphenomenalism can be Handled
1. The Apparent Problem--Given evolution, only features that are conducive to survival are selected.  If ephiphenomenalism is true, the non-physical aspects of color vision and other qualia do nothing.  So how is it that these non-physical aspects survive natural selection?
2. Reply:
• The apparent causal role of qualia is simply that: apparent.  Qualia come about as a consequence of something else that is necessary for survival.
• Evolution need only select for brain states.  The non-physical mental states that are given off are extra.

Problems with the Knowledge Argument

1. Argument Also Works Against Dualism
1. Mary knows all non-physical facts about color vision.
• Suppose that Mary is a brilliant student of all things "soulish."  She has learned everything that goes on in the soul (immarterial part) when color vision occurs.  She knows all of the non-physical facts about color vision. 
  
• Moreover, Mary has been colorblind since birth.  But, of course, she could still learn what happens in the soul when color vision occurs even if she doesn't see color.
  
2. Mary does not know all facts about color vision.
• Demonstrated by Mary's learning when seeing red.
• It seems that if Mary's colorblindness were corrected, she would learn something new about the color red when she saw it for the first time, namely, what it is like to see red.
3. Therefore, some facts about color vision are left out of non-physical account
4. Therefore, some aspects of color vision (and other qualia) are physical.
2. Fallacy of Equivocation: Two Senses of "Know"
1. Knowledge by Description (Discursive)
• We gain knowleged by description of x by learning the features of x.
• This is the sort of knowlege referred to in the first premise.
2. Knowledge by Acquaintance (Non-Discursive)
• We gain knowledge by acquaintance of x by experiencing x.
• This is the sort of knowledge referred to in the second premise.
3. Since "know" is used differently in premises one and two, the argument is invalid.