Can physicalism account for qualia?
Can physicalism account for qualia? Physicalist theories of mind presented a new alternative for those who rejected dualism yet could not bring themselves to endorse behaviourism. Proposing that that mental events are physical ones, physicalist theories lack the mystical quality of dualist explanations of mind, and avoid behaviourism's greatest flaw: the complete denial (or glossing over) of inner mental life. Simple introspection seems to make the denial of this inner mental life quite ridiculous – all philosophers are familiar with Descartes' Cogito Ergo Sum (2006). However, as with behaviourism, this inner mental life creates a difficult obstacle for physicalism to surmount. In particular, one aspect of mental phenomena, called “qualia” (singular “quale”), has caused problems for physicalism. Qualia capture the subjective, phenomenological, part of mental life. These problems have seen many incarnations; those posited by Jackson (1982), Nagel (1974) and Kripke (1971) are perhaps the most famous and well-stated of these. Frank Jackson constructed a thought experiment to attempt to show that one can have all the physical facts about something yet still gain new information in the experiencing of it. Thomas Nagel focused on point of view to try to show that an objective theory cannot capture subjective facts. Kripke did not not strictly put forward an argument from qualia, but rather from the nature of identity. Nevertheless his argument attempts to show that qualia cannot be identified with a physical state. All three arguments try to prove the impossibility of current physicalist theories accounting for qualia; their varying success (and failure) will be discussed. Even if these arguments are fallible, it does not necessarily mean that we will ever gain a satisfactory physicalist account of qualia (or any other account); McGinn (1989) proposes this idea, putting forward an argument reminiscent of Godel's incompleteness theorems (Heil, 2004, p.756). There are also other possible reasons that the two may be impossible to reconcile – not because physicalism is false, but rather because there is something wrong about our notion of qualia.Before the compatibility of physicalism and qualia can be considered, first we must make sure that we have clear ideas of each concept. There are many forms of physicalism. Physicalist theories all share one thing in common: they all make the claim that there is only one type of “stuff” - the physical – and that the mind is therefore a physical entity. This is usually taken to mean that our mental lives should be describable in physical terms, though it is important to note that this is not logically necessary: it is not a contradiction to hold that our mental lives are physical, yet indescribable (possibly because we lack the linguistic sophistication to do so). However, the ability to describe the mental in terms of the physical is usually held by physicalists, and accordingly many arguments focus on this. The motivation behind this assertion of the describability of the mental in terms of the physical is clear: without it, a physicalist conception of mind would be scientifically useless, a conclusion unpalatable to physicalists – especially given the close ties between physicalism and neuroscience. For the purpose of this paper, we may consider an attack on describability an attack on physicalism in general. The basic expression of physicalism is that of mind-brain identity, which suggests that a mental event is identical with a brain state. For example, being in pain would be identified with the brain being in a certain state, thinking about tennis with another, and so on. This position has evolved into more sophisticated forms in response to various objections. Most notably “token identity” was developed in response to objections about the necessary nature of identification of a mental event “X” with a brain state “Y”. Token identity allows that my brain state for pain may be different from another person's (or even my own at another
time): it merely states that any given mental event will be identified with a token (particular instance of a) brain state. Functionalism is a type of physicalism which holds that the mind, while still physical, is defined by the causal and functional relations that it consists of, and it only happens that, in the case of humans, these relations are seated in the brain. It is equally possible, under a functionalist understanding of mind, that minds may appear in other physical systems. This view is not incompatible with token identity theory (Fodor, 1981, p.174), and as such functionalism may be ...
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time): it merely states that any given mental event will be identified with a token (particular instance of a) brain state. Functionalism is a type of physicalism which holds that the mind, while still physical, is defined by the causal and functional relations that it consists of, and it only happens that, in the case of humans, these relations are seated in the brain. It is equally possible, under a functionalist understanding of mind, that minds may appear in other physical systems. This view is not incompatible with token identity theory (Fodor, 1981, p.174), and as such functionalism may be considered a more sophisticated expression of this.Qualia are an aspect of conscious experience. The term is closely linked with the idea of a phenomenology: that there is something which it is like to be something. It is like something to be a human, but there is not something which it is like to be a rock. Thus humans have a phenomenology, whereas rocks do not. A quale is a specification of the phenomenological aspect of an experience – what it is like to experience that thing. Examples of qualia include the smell of bacon cooking, or the perception of a colour (despite these examples, note that qualia are not necessarily sensory in nature). Qualia are usually held to be subjective and irreducible (Cottingham, 1987), though these claims may be exactly those contested by physicalists.We can now discuss whether or not physicalism can account for qualia. It should be noted that this is a question of the possibility of compatibility, not a question asking if there is, at present, a theory which successfully combines the two. That question is uninteresting as the answer is clearly the negative: there is no complete scientific theory of consciousness, if such a thing is possible. As we are interested in possibility, opponents of physicalism must therefore argue the impossibility of its accounting for qualia. I shall not present these arguments chronologically, but rather in the order in which the arguments (to me) seem to naturally unfold.Frank Jackson, in his paper “Epiphenomenal Qualia” (1982), describes a now-famous thought experiment. It unfolds as follows: imagine a scientist, Mary, who is confined to a black and white room and only ever sees black and white things. In this room, she learns all the physical facts there are to know about colour and colour experiences. Suppose she then goes into the world and sees colour for the first time. Jackson holds than when she sees colour for the first time, she will have learnt something new. His argument is therefore that one can know everything physical about an experience yet still not have all the facts (the qualia will have been missed out). Therefore there are non-physical facts (qualia) which, as it is interested only in the physical, physicalism cannot account for.This argument commits three errors, two stated by Gilbert Harman (1990). The first relies on a technical distinction between the qualities of an intentional object, and the qualities of the experience of that object. When Mary sees a colour for the first time, this colour is a quality of whatever it is she is observing, not her experience. It does not make sense, unless one is speaking poetically, to say that one has had a “red experience”. It does, however, make sense that an object is red, and you are experiencing that object. As such, Mary's first experience of colour should not be considered to be qualia as the colour is intrinsic to the object, not the subject. While possessing a certain elegance, this argument is not entirely convincing. It is true that “I have a red experience” is nonsense, yet it is still the case that one can experience the colour red. The qualia does not appear to have gone away at all – there is something which it is like to experience red. Harman's second objection is based on the function of representation: “to know what it is like to see something red is to be capable of representing to yourself something's being red” (ibid, p.650). There is therefore a fact that Mary, when still in her black and white room, cannot know: the concept of a visual experience involving this representation. Again, this argument is slightly unconvincing. If anything, it supports Jackson's argument, in that it would seem to be saying that Mary must know what it is like to experience a colour to be able to know all the facts about it. There is a much simpler objection to Jackson's argument, and this is to point out its obvious circularity. By saying that Mary knows all the physical facts about colour, and then that she sees a colour and learns something new, and then conclude that there are non-physical elements of colour experiences, one is begging the question. It holds as an assumption that all the physical facts did not encompass the qualia. This is exactly Jackson's conclusion, and exactly that which physicalists dispute.Although it was published before Jackson's article, Nagel's argument (1974) against physicalism is a more sophisticated one. A physicalist theory, by definition, is objective. A person's mind is there to be studied objectively by any sufficiently equipped and knowledgeable observer. Qualia, however, are subjective. They are unique to the subject. Nagel uses the example of a bat's sensory perception as an example of qualia, stating that we cannot conceive what it is like to be a bat because we have no way of feeling a bat's qualia purely by explaining it in physical terms: while we may understand the principles of sonar, there is still no way we can know what it is like to experience sensory perception via this process, in the first person. As such objective physicalist theories cannot capture what it is like to have a point of view.Physicalists who wish to counter Nagel's argument can take one of two routes. Either they can attempt to deny the subjectivity of qualia, or argue that the subjectivity of qualia does not mean they cannot be physical. To deny the subjectivity of qualia appears contradictory at first, but it may just be that we (or Nagel) lack sufficient knowledge, imagination or processing power for it to appear plausible to us. Take the case of the bat. Nagel argues that we cannot know what it is like to be a bat by objective analysis of its brain and perception systems. Certainly this is the case now, but imagine that in the future science has advanced so far as to provide a complete explanation of how the bat's perception and “thinking” works. Still, this does not appear enough to provide what it is like to be a bat. However, it is helpful here to make a comparison to computer science. An experienced and knowledgeable programmer can look at the code for an unknown program without being able to discern the nature or purpose of the program (unless it is a very simple program). This is not because there is something about the program that is not included in the code: the code is everything that there is. Rather, it is because the human programmer does not possess the computational power to look at code as a single object and mentally compile it into what the program would be. With this in mind, we can consider the bat situation again. Inability to determine what it is like to be a bat may be not because the bat's physical brain does not possess the information that encodes this quale, but rather because we lack the processing ability to successfully mentally transform this data into an explicit idea (or “feel”). As such, it is not an argument against physicalism or for the subjectivity of qualia – the quale may be entirely physical, and thus objective – but simply a statement of the limited power of human imagination (or processing power). Alternatively, a physicalist may make the point that “subjective” and “physical” are not opposites, and do not entail a contradiction. Accordingly, a quale may be subjective and physical without contradiction. However, this argument comes with a sacrifice: by claiming that the physical mind is, despite its physical nature, subjective rather than objective, one loses the claim of describability that is so essential to neuroscience and the normal understanding of physicalism. Further, it is not clear how a physical thing may be not objective.Kripke's argument against physicalism (1971) is essentially quite simple. Consider an identity statement such as “1 + 1 = 2”. It is impossible for us to imagine a world in which “1 + 1” did not equal “2”. This is, Kripke argues, because they are identical. Now consider the claim that a quale is identical to a brain state (or a token brain state, or a functional state). If this were the case we should not be able to imagine, by the nature of identity, a world in which the quale is not a brain state (or a token brain state, or a functional state). We quite clearly can: we can imagine a world in which the dualist conception of mind was true. Thus, Kripke claims, the two cannot be identical with each other.This argument has a conception of identity which may not be accurate. As Harcastle argues (1996), we can imagine a world in which “E = MC2” did not hold (due to different starting conditions of the universe), yet they are identical. Perhaps Kripke's objection of identity is merely a problem of our notation: we do not have different notation of things that are necessarily (or a priori) identical (as numbers are) and those which are contingently identical (as “E = MC2” is). Kripke's objection would then only have impact if physicalists claimed that minds and brains were a priori identical, which they do not. Proponents of Kripke might argue that when we say that “E = MC2” might have been different, we are not imagining “E” (energy) properly (ibid). Were we imagining it properly, by the definition supplied (“E = MC2”), we would be incapable of imagining it as anything other than “MC2”. However, this is confusing the “E = MC2” statement for something which is a priori identical, not contingently so. It is not a definition, but a statement of fact. Moreover, this “imagining incorrectly” argument does nothing to harm the physicalists, as they can simply reply with the claim that, when we imagine a world where minds are not brain states (or whatever flavour of physicalism is being used) we are imagining minds incorrectly.It would appear that these attempts by non-physicalists to prove the impossibility of physicalism accounting for qualia fall short of absolute proof. Despite the counter-arguments elaborated above, some may still find the arguments convincing, and doubt the abilities of physicalism to provide a physical explanation for qualia. This is not surprising: the issue rarely sees any converts. This lack of conversion may give a hint towards the nature of the debate as unsolvable – not because of sheer stubbornness (though this certainly may be a factor) but due to a fundamental flaw in asking the question in the first place.McGinn argues to this effect in “Can We Solve the Mind-Body Problem?” (1989). While he does not deny physicalism, he suggests a reason for our inability to fully comprehend how it could be that a physical mind give rise to qualia. He takes note of the commonly-held belief that there are some pieces of knowledge that the human brain cannot understand in principle: that the way the human mind is set-up is such that it is not suited to the comprehension of certain things. The strangeness of , and our inability to truly comprehend, quantum effects (except, perhaps, through mathematisation) certainly gives credence to this idea. A commonly proposed explanation is that our minds evolved to deal with objects on a certain scale (not too small and not too large), and as such we are not equipped to intuitively understand the behaviours of objects in other scales (such as quantum scales, or relativistic ones). McGinn then putts forward the idea that the workings of our own brains/minds may be one of these things which we cannot fully comprehend, in principle.There is another way to explain the apparent (to many, at least) insolubility of the clash between physicalism and qualia. It is probable that our intuitions about the way our minds work are at least partly incorrect. Already they are dissolving: our intuitions suggest to us that our thinking is continuous, but research points towards the possibility that we think in “frames”, like a video camera takes apparently smooth video (Fox, 2009). With our mental intuitions in doubt, qualia too come into question. The notion of “qualia” is based entirely on our mental intuitions, our phenomenology. It is all about the way things seem to us. And yet the way things seem to us may be false. It is entirely possible that a complete neuroscience may still not reveal any explanation for qualia. Some would take this to mean that neuroscience has missed something. However, this view may not take seriously the ability of science to correct our intuitions – something which science has been doing for centuries. If a complete physicalist theory of mind did not account for qualia, then it is more likely that our notion of qualia is incorrect, not our science. This is not to say that our qualia do not exist – clearly they do – but rather that they do not exist as we think they do. They may not be irreducible, for example, but instead be a coming together of many parts of the brain working in concert (possibly even epiphenomenal, as Jackson (1982) speculates – though he is anti-physicalist). If this is the case, qualia are merely a symptom of our ignorance, and when that ignorance is corrected, the problem of the compatibility of physicalism and qualia may dissolve into nonsensicality.The arguments against physicalism fail to prove beyond doubt that it is impossible for physicalism to account for qualia. Further, the final obstacle to accepting that physicalism can describe qualia – our intuitions – can be called into doubt by a proper appreciation for the power of science. Certainly this is not the end of the discussion. It only shows that it is not impossible for physicalism to explain qualia (conditional on the non-emergence of a new argument to show the opposite). The actual explanation is the hard part, and is yet to come – if it is to come at all. That it is possible for physicalism to account for qualia does not mean that it will. It is possible that there is some better hypothesis and that physicalism is false, despite its possibility of being true. Until that hypothesis emerges, however, physicalism still looks like the best option. BibliographyLiteratureCottingham, J, 1987, “Qualia”, in “The Oxford Companion to Mind”, ed. Gregory, R, 1987, Oxford University Press: New York.Descartes, R, 2006, “Meditations on First Philosophy”, in “Descartes Selected philosophical Writings”, 2006, trans. Cottingham, Stoothoff and Murdoch, Cambridge University Press: New York.Fodor, J, 1981, “The Mind-Body Problem”, in “Philosophy of Mind: A Guide and Anthology”, 2004, ed. John Heil, Oxford University Press: Oxford.Fox, D, 2009, “The time machine inside your head”, New Scientist, 2731, p.32-37.Harcastle, V, 1996, “The Why of Consciousness: A Non-Issue for Materialists”, in “Philosophy of Mind: A Guide and Anthology”, 2004, ed. John Heil, Oxford University Press: Oxford.Heil, J, 2004, Introduction to Part XI, in “Philosophy of Mind: A Guide and Anthology”, 2004, ed. 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