Editing Knowledge argument (section)

=== Design of the thought experiment ===
Some have objected to Jackson's argument on the grounds that the scenario described in the thought experiment itself is not possible. For example, [[Evan Thompson]] questioned the premise that Mary, simply by being confined to a monochromatic environment, would not have any color experiences, since she may be able to see color when dreaming, after rubbing her eyes, or in afterimages from light perception.<ref>{{Cite book |last=Thompson |first=Evan |author-link=Evan Thompson |title=Colour vision: a study in cognitive science and the philosophy of perception |date=1995 |publisher=Routledge |isbn=978-0-415-11796-8 |edition=1. publ |series=Philosophical issues in science |location=London}}</ref> However, Graham and Horgan suggest that the thought experiment can be refined to account for this: rather than situating Mary in a black and white room, one might stipulate that she was unable to experience color from birth, but was given this ability via medical procedure later in life.<ref>{{Cite journal|last1=Graham|first1=George|last2=Horgan|first2=Terence|date=2000-05-01|title=Mary Mary, Quite Contrary|journal=Philosophical Studies|language=en|volume=99|issue=1|pages=59–87|doi=10.1023/A:1018779425306|s2cid=170191214|issn=0031-8116}}</ref> Nida-Rümelin recognizes that one might question whether this scenario would be possible given the science of color vision (although Graham and Horgan suggest it is), but argues it is not clear that this matters to the efficacy of the thought experiment, provided we can at least conceive of the scenario taking place.<ref name="plato" />

Objections have also been raised that, even if Mary's environment were constructed as described in the thought experiment, she would not, in fact, learn something new if she stepped out of her black and white room to see the color red. Daniel Dennett asserts that if she already truly knew "everything about color", that knowledge would necessarily include a deep understanding of why and how human neurology causes us to sense the "qualia" of color. Moreover, that knowledge would include the ability to functionally differentiate between red and other colors. Mary would therefore already know exactly what to expect of seeing red, before ever leaving the room. Dennett argues that functional knowledge is identical to the experience, with no ineffable "qualia" left over.<ref>See {{Harvnb|Dennett|1991|p=398}} & {{Harvnb|Dennett|2006}}.</ref> J. Christopher Maloney argues similarly: <blockquote>If, as the argument allows, Mary does understand all that there is to know regarding the physical nature of colour vision, she would be in a position to imagine what colour vision would be like. It would be like being in physical state S<sub>k</sub>, and Mary knows all about such physical states. Of course, she herself has not been in S<sub>k</sub>, but that is no bar to her knowing what it would be like to be in S<sub>k</sub>. For she, unlike us, can describe the nomic relations between S<sub>k</sub> and other states of chromatic vision...Give her a precise description in the notation of neurophysiology of a colour vision state, and she will very likely be able to imagine what such a state would be like.<ref>{{Cite journal|last=Maloney|first=J. Christopher|date=1985-03-01|title=About being a bat|journal=Australasian Journal of Philosophy|volume=63|issue=1|pages=26–49|doi=10.1080/00048408512341671|issn=0004-8402}}</ref> </blockquote>Surveying the literature on Jackson's argument, Nida-Rümelin identifies, however, that many simply doubt the claim that Mary would not gain new knowledge upon leaving the room, including physicalists who do not agree with Jackson's conclusions. Most cannot help but admit that "new information or knowledge comes her way after confinement," enough that this view "deserves to be described as the received physicalist view of the Knowledge Argument."<ref name="plato" />

Some philosophers have also objected to Jackson's first premise by arguing that Mary could not know all the physical facts about color vision prior to leaving the room. Owen Flanagan argues that Jackson's thought experiment "is easy to defeat". He grants that "Mary knows everything about color vision that can be expressed in the vocabularies of a complete physics, chemistry, and neuroscience", and then distinguishes between "metaphysical physicalism" and "linguistic physicalism": <blockquote>Metaphysical physicalism simply asserts that what there is, and all there is, is physical stuff and its relations. Linguistic physicalism is the thesis that everything physical can be expressed or captured in the languages of the basic sciences…Linguistic physicalism is stronger than metaphysical physicalism and less plausible. </blockquote>Flanagan argues that, while Mary has all the facts that are expressible in "explicitly physical language", she can only be said to have all the facts if one accepts linguistic physicalism. A metaphysical physicalist can simply deny linguistic physicalism and hold that Mary's learning what seeing red is like, though it cannot be expressed in language, is nevertheless a fact about the physical world, since the physical is all that exists.<ref>{{Cite book|url=http://webcat1.library.ubc.ca:80/vwebv/holdingsInfo?bibId=881540|title=Consciousness reconsidered|last=Flanagan|first=Owen J.|date=1992-01-01|publisher=MIT Press|isbn=978-0262061483|location=Cambridge, Massachusetts}}</ref> Similarly to Flanagan, Torin Alter contends that Jackson conflates physical facts with "discursively learnable" facts, without justification: <blockquote>...some facts about conscious experiences of various kinds cannot be learned through purely discursive means. This, however, does not yet license any further conclusions about the nature of the experiences that these discursively unlearnable facts are about. In particular, it does not entitle us to infer that these experiences are not physical events.<ref>{{Cite journal|last=Alter|first=Torin|date=1998|title=A Limited Defense of the Knowledge Argument|jstor=4320837|journal=Philosophical Studies|volume=90|issue=1|pages=35–56|doi=10.1023/a:1004290020847|s2cid=170569288}}</ref> </blockquote>Nida-Rümelin argues in response to such views that it is "hard to understand what it is for a property or a fact to be physical once we drop the assumption that physical properties and physical facts are just those properties and facts that can be expressed in physical terminology."