Editing Physicalism (section)

== Arguments against physicalism ==

=== Knowledge argument ===
{{See also|Mary's room}}
Though there have been many objections to physicalism throughout its history, many of them are concerned with the apparent contradiction of the existence of [[qualia]] in an entirely physical world. The most popular argument of this kind is the so-called knowledge argument as formulated by [[Frank Cameron Jackson|Frank Jackson]], titled "[[Mary's room]]".<ref>Jackson, Frank (1982). "Epiphenomenal Qualia". ''Philosophical Quarterly''. '''32''' (127): 127–136. [[Doi (identifier)|doi]]:10.2307/2960077. [[JSTOR (identifier)|JSTOR]] 2960077.</ref>

The argument asks us to consider Mary, a girl who has been forced to discover the world from a black-and-white room via a black-and-white television monitor throughout her life. She has access to books containing all physical knowledge. During her time in the room, she learns all the physical facts about the world, including all the physical facts about color. To a physicalist, it would seem that this entails Mary knowing everything about the world. But once she is let out of the room and into the world, it becomes apparent that there were things Mary did not know about the world, such as the ''feeling'' or ''experience'' of seeing color. If Mary did not have such knowledge, how can it be said that everything supervenes upon the physical?

==== Physicalist response ====
One response, developed by [[Lawrence Nemerow]] and [[David Kellogg Lewis|David Lewis]], is known as the ability hypothesis. The ability hypothesis distinguishes between propositional knowledge, such as "Mary knows that the sky is typically blue during the day", and knowledge-how, such as "Mary knows how to climb a mountain", and says that all Mary gains from seeing the world in color is knowledge-how. According to this response, Mary does gain knowledge from her experience, but it is not the propositional knowledge required for the knowledge argument to be logically sound.<ref>{{Cite book|url=https://plato.stanford.edu/entries/physicalism/|title=The Stanford Encyclopedia of Philosophy|first=Daniel|last=Stoljar|chapter=Physicalism |editor-first1=Edward N.|editor-last1=Zalta|editor-first2=Uri|editor-last2=Nodelman|date=March 31, 2024|publisher=Metaphysics Research Lab, Stanford University|via=Stanford Encyclopedia of Philosophy}}</ref>

=== Argument from philosophical zombies ===
One commonly issued challenge to a priori physicalism and physicalism in general is the "conceivability argument", or [[zombie argument]].<ref>See Chalmers, 2009.</ref> The conceivability argument runs roughly as follows:

# According to physicalism, everything in our world (including consciousness) is physical.
# Thus, if physicalism is true, a metaphysically possible world in which all physical facts are the same as in the actual world contains everything that exists in the actual world. In particular, conscious experience exists in such a world.
# We can conceive of a world physically indistinguishable from our world but in which there is no consciousness (a zombie world). From this it follows that such a world is metaphysically possible.
# Therefore, physicalism is false. (This [[Logical consequence|follows from]] (2) and (3) by ''[[modus tollens]]''.)<ref>See Chalmers, 2009</ref>

The possibility of philosophical zombies (p-zombies) entails that mental states do not supervene upon physical states, and thus that physicalism is false. Australian philosopher [[David Chalmers]] argues that the conceivability of a zombie entails a metaphysical possibility.<ref>{{cite book |author=Chalmers, David |title=The Conscious Mind |publisher=Oxford University Press |year=1996 |location=Oxford, England}}</ref> 

==== Physicalist response ====
[[Galen Strawson]] argues that it is impossible to establish the conceivability of zombies, so the argument, lacking its first premise, fails.<ref>{{cite book |last1=Strawson |first1=Galen |author-link1=Galen Strawson |title=Towards a Science of Consciousness III |date=1999 |editor1-last=Hameroff |editor1-first=S. |editor2-last=Kaszniak |editor2-first=A. |editor3-last=Chalmers |editor3-first=D.}}</ref>

[[Daniel Dennett]] argues that "when philosophers claim that zombies are conceivable, they invariably underestimate the task of conception (or imagination), and end up imagining something that violates their own definition".<ref name="Dennett1991">{{cite book |last=Dennett |first=Daniel C. |url=https://archive.org/details/consciousnessexp00denn |title=Consciousness Explained |publisher=Little, Brown and Co. |year=1991 |isbn=0-316-18065-3 |location=Boston, Toronto, London}}</ref><ref name="Dennett1995">{{cite book |last=Dennett |first=Daniel C. |url=https://archive.org/details/darwinsdangerous0000denn |title=Darwin's Dangerous Idea |publisher=Simon & Schuster |year=1995 |isbn=0-684-82471-X |location=New York |page=[https://archive.org/details/darwinsdangerous0000denn/page/322 322] |url-access=registration}}</ref> He coined the term "zimboes"—p-zombies that have [[Second-order logic|second-order beliefs]]—in arguing that p-zombies are incoherent:<ref>Dennett 1995; 1999</ref> "Zimboes think<sup>Z</sup> they are conscious, think<sup>Z</sup> they have qualia, think<sup>Z</sup> they suffer pains—they are just 'wrong' (according to this lamentable tradition), in ways that neither they nor we could ever discover!"<ref name="Dennett1995" /> In ''The Unimagined Preposterousness of Zombies'' (1995), Dennett compares consciousness to [[health]].

{{Quotation|Supposing that by an act of stipulative imagination you can remove consciousness while leaving all cognitive systems intact—a quite standard but entirely bogus feat of imagination—is like supposing that by an act of stipulative imagination, you can remove health while leaving all bodily functions and powers intact. … Health isn't that sort of thing, and neither is consciousness.}}[[Michael P. Lynch|Michael Lynch]] argues that the zombie conceivability argument forces us to either question whether we actually have consciousness or accept that zombies are impossible. If zombies falsely believe they are conscious, how can we be sure we are not zombies? We may believe we have conscious mental states when in fact we merely hold a false belief. Lynch thinks denying the possibility of zombies is more reasonable than questioning our own consciousness.<ref>Lynch, Michael P. (2006). Zombies and the case of the phenomenal pickpocket. Synthese 149 (1):37-58.</ref>

[[Daniel Stoljar]] has proposed what he calls "the [[phenomenal concept strategy]]".<ref>See Stoljar, 2005</ref> Roughly, the phenomenal concept strategy attempts to show that only the ''concept'' of consciousness—not the ''property''—is in some way "special" or [[sui generis]].<ref>cf. Stoljar, 2005</ref> 

=== Hempel's Dilemma ===
{{Main|Hempel's Dilemma}}
Physicalists have traditionally opted for a "theory-based" characterization of the physical in terms of either current physics<ref>See e.g., Smart, 1978; Lewis, 1994.</ref> or a future (ideal) physics.<ref>See e.g., Poland, 1994; Chalmers, 1996; Wilson, 2006.</ref> Hempel's Dilemma (named after the philosopher of science [[Carl Gustav Hempel]]) attacks physicalism by arguing that both of these approaches are problematic. If, on the one hand, we define the physical by reference to current physics, then physicalism is very likely to be false because it is very likely (by pessimistic meta-induction<ref>see Vincente, 2011</ref>) that much of current physics is false. If, on the other hand, we define the physical in terms of a future (ideal) or completed physics, then physicalism is hopelessly vague or indeterminate.<ref>See Hempel, 1969, pp.180-183; Hempel, 1980, pp.194-195.</ref>

==== Physicalist response ====
Some physicalists, like Andre Melnyk, accept the dilemma's first horn: they accept that the current definition of physicalism is very likely false as long it is more plausible than any currently formulated rival proposition, such as dualism. Melnyk maintains that this is the attitude most scientists hold toward scientific theories anyway. For example, a defender of evolutionary theory may well accept that its current formulation is likely to be revised in the future but defend it because they believe current evolutionary theory is more likely than any current rival idea, such as creationism. Thus Melnyk holds that one should define physicalism in relation to current physics and have a similar attitude toward its truth as most scientists have toward the truth of currently accepted scientific theories.<ref name="Melnyk1997" />

Some physicalists defend physicalism via alternative characterizations of physicalism. [[Frank Cameron Jackson|Frank Jackson]], for example, has argued for an "object-based" conception of the physical.<ref>See Jackson, 1998, p.7; Lycan, 2003.</ref> [[David Papineau]]<ref>See Papineau, 2002</ref> and Barbara Montero<ref>See Montero, 1999</ref> have argued for a "via negativa" characterization of the physical.<ref>See Montero and Papineau, 2005</ref> The gist of this approach is characterize the physical in terms of what it is not: the mental. In other words, the via negativa strategy understands the physical as the non-mental. 

=== Argument from overdetermination ===
[[File:Figure1.gif|right|thumb|Figure demonstration how M1 and M2 are not reduced to P1 and P2.]]
[[Jaegwon Kim]] objects to non-reductive physicalism based on the problem of [[overdetermination]].<ref name="auto">(2005) ''Physicalism, or Something Near Enough'', Princeton University Press</ref> He proposes (using the chart on the right) that ''M1'' causes ''M2'' (these are mental events) and ''P1'' causes ''P2'' (these are physical events). ''M1'' has ''P1'' as its supervenience base (P1 realizes M1), and ''M2'' has ''P2'' as its supervenience base (P2 realizes M2). If ''P1'' causes ''P2'' and M1 causes M2, then we have a case of causal overdetermination. To avoid this causal overdetermination, either M1 or P1 must be eliminated as a cause of P2. Because of the principle of the [[causal closure]] of the physical, M1 is excluded. The non-reductive physicalist is then forced to choose between two unappealing options: accept overdetermination or embrace [[epiphenomenalism]]. Kim thus argues that mental causation can be preserved only by embracing a reductionist view, whereby mental properties are considered causally efficacious by being reduced to physical properties.<ref name="auto"/>

=== Argument from first-person perspectives ===
[[Christian List]] argues that the existence of first-person perspectives, i.e. one existing as oneself and not as someone else, is a compelling argument against physicalism. List argues that since first-personal facts cannot supervene on physical facts, this refutes not only physicalism, but also most forms of dualism that have purely third-personal metaphysics.<ref>{{cite web |url=https://philpapers.org/rec/LISTFA |title=The first-personal argument against physicalism |last=List |first=Christian |date=2023 |website= |publisher= |access-date=19 May 2025 |quote=}}</ref> List also argues that there exists a "quadrilemma" for theories of consciousness. He claims that at most three of the following metaphysical claims can be true: 'first-person [[Philosophical realism|realism]]', 'non-[[solipsism]]', 'non-fragmentation', and 'one world' – and thus at least one of these four must be false.<ref>{{cite web |url=https://philarchive.org/rec/LISAQF |title=A quadrilemma for theories of consciousness |last=List |first=Christian |date=2023 |website= |publisher=The Philosophical Quarterly |access-date=19 May 2025 |quote=}}</ref> List has proposed a model he calls the "many-worlds theory of consciousness" in order to reconcile the subjective nature of consciousness without lapsing into solipsism.<ref>{{cite web |url=https://philarchive.org/rec/LISTMT-2 |title=The many-worlds theory of consciousness |last=List |first=Christian |date=2023 |website= |publisher=The Philosophical Quarterly |access-date=19 May 2025 |quote=}}</ref> These ideas relating to first-person perspectives are related to the [[vertiginous question]] proposed by Benj Hellie.<ref>{{cite journal|last=Hellie|first=Benj|year=2013|title=Against egalitarianism|journal=Analysis|volume=73|issue=2|pages=304–320|doi=10.1093/analys/ans101}}</ref>