Editing Mind–body dualism (section)

===The subjective argument===
An important fact is that minds perceive intra-mental states differently from sensory phenomena,<ref>{{cite journal|last=Prinz|first=Wolfgang|title=Why don't we perceive our brain states?|journal=European Journal of Cognitive Psychology|date=January 1992|volume=4|issue=1|doi=10.1080/09541449208406240 |pages=1–20}}<!--|access-date=19 November 2012--></ref> and this cognitive difference results in mental and physical phenomena having seemingly disparate properties. The subjective argument holds that these properties are irreconcilable under a physical mind.

Mental events have a certain ''subjective'' quality to them, whereas physical ones seem not to. So, for example, one may ask what a burned finger feels like, or what the blueness of the sky looks like, or what nice music sounds like.<ref name="Nag">[[Thomas Nagel|Nagel, Thomas]]. 1986. ''[[The View from Nowhere]]''. New York: Oxford University Press.</ref> Philosophers of mind call the subjective aspects of mental events ''[[qualia]].'' There is something ''that it's like'' to feel pain, to see a familiar shade of blue, and so on. There are ''qualia'' involved in these mental events. And the claim is that qualia cannot be reduced to anything physical.<ref name="Hart" />

[[Thomas Nagel]] first characterized the problem of qualia for physicalistic monism in his article, "[[What Is It Like to Be a Bat?]]". Nagel argued that even if we knew everything there was to know from a third-person, scientific perspective about a bat's sonar system, we still wouldn't know what it is like to ''be'' a bat. However, others argue that ''qualia'' are consequent of the same neurological processes that engender the bat's mind, and will be fully understood as the [[neural correlates of consciousness|science]] develops.<ref>{{cite book|last=Dennett|first=Daniel C.|title=Consciousness Explained|year=1991|publisher=Little, Brown and Co|isbn=978-0-316-18065-8|url=https://archive.org/details/consciousnessexp00denn}}</ref>

[[Frank Cameron Jackson|Frank Jackson]] formulated his well-known ''[[knowledge argument]]'' based upon similar considerations. In this [[thought experiment]], known as [[Mary's room]], he asks us to consider a neuroscientist, Mary, who was born, and has lived all of her life, in a black and white room with a black and white television and computer monitor where she collects all the scientific data she possibly can on the nature of colours. Jackson asserts that as soon as Mary leaves the room, she will come to have new knowledge which she did not possess before: the knowledge of the experience of colours (i.e., what they are like). Although Mary knows everything there is to know about colours from an objective, third-person perspective, she has never known, according to Jackson, what it was like to see red, orange, or green. If Mary really learns something new, it must be knowledge of something non-physical, since she already knew everything about the physical aspects of colour.<ref>Jackson, Frank. 1977. ''Perception: A Representative Theory''. Cambridge: Cambridge University Press.</ref>

However, Jackson later rejected his argument and embraced [[physicalism]].<ref>{{cite book|last=O'Hear|first=Anthony|title=Mind and Illusion, in "Minds and Persons"|year=2003|publisher=Cambridge University Press|page=251}}</ref> He notes that Mary obtains knowledge not of color, but of a new intramental state, ''seeing color''.<ref name="Jackson 2003 251" /> Also, he notes that Mary might say "wow," and as a mental state affecting the physical, this clashed with his former view of [[epiphenomenalism]]. [[David Kellogg Lewis|David Lewis]]' response to this argument, now known as the ''ability'' argument, is that what Mary really came to know was simply the ability to recognize and identify color sensations to which she had previously not been exposed.<ref>Lewis, David. [1988] 1999. "What Experience Teaches." pp. 262–290 in ''Papers in Metaphysics and Epistemology'', Cambridge: Cambridge University Press.</ref> [[Daniel Dennett]] and others also provide [[Mary's room#Objections|arguments against this notion]].