Making sense of causal interactions between consciousness and brain

MAKING SENSE OF CAUSAL INTERACTIONS BETWEEN CONSCIOUSNESS AND BRAIN Journal of Consciousness Studies, 9(11), 2002, pp. 69-95. Max Velmans, Department of Psychology, Goldsmiths, University of London, New Cross, London SE14 6NW, England. ABSTRACT. My target article (henceforth referred to as TA) presents evidence for causal interactions between consciousness and brain and some standard ways of accounting for this evidence in clinical practice and neuropsychological theory. I also point out some of the problems of understanding such causal interactions that are not addressed by standard explanations. Most of the residual problems have to do with ho to oss the e pla ato gap f o o s ious ess to ai . I the list so e of the reasons why the route across this gap suggested by physicalism won't work, in spite of its current popularity in consciousness studies. My own suggested route across the explanatory gap is more subterranean, where consciousness and brain can be seen to be dual aspects of a unifying, psychophysical mind. Some of the steps on this deeper route still have to be filled in by empirical research. But (as far as I can judge) there are no gaps that cannot be filled—just a different way of understanding consciousness, mind, brain and their causal interaction, with some interesting consequences for our understanding of free will. The commentaries on TA examined many aspects of my thesis viewed from both Western and Eastern perspectives. This reply focuses on how dual-aspect monism compares with currently popular alternatives such as o edu ti e ph si alis , la ifies o app oa h, a d e o side s ho ell this add esses the ha d p o le s of o s ious ess. We e-examine how conscious experiences relate to their physical/functional correlates and whether useful analogies can be drawn with other, physical relationships that appear to have dual-aspects. We also examine some fundamental differences between Western and Eastern thought about whether the existence of the physical world or the existence of consciousness can e take fo g a ted ( ith o se ue tial diffe e es a out hi h of these is ha d to understand). I then suggest a form of dual-aspect Reflexive Monism that might provide a path between these ancient intellectual traditions that is consistent with science and with common sense. Additional Note for 2012 upload on Academia.edu: This reply responds to thoughtful commentaries on the target article by John Kihlstrom, Todd Feinberg, Steve Torrance, Robert van Gulick, Jeffrey Gray and K. Ramakrisna Rao. One commentary by Ron Chrisley and Aaron Sloman seriously misrepresented my views and then proceeded to criticize their own misrepresentation in ways that I make clear in my response. Ten years after its initial publication, as far as I can tell, the analysis of consciousness-brain causal interactions presented in "How could conscious experience affect brains?" still conforms closely to both the findings of science and to everyday experience. " I would like to thank the commentators on TA for their many excellent commentaries. To simplify the process of relating these commentaries and my replies to the original text, I will deal with them according to topic in the sequence that these topics are treated in TA. At 1 various points I refer to more detailed treatments of the issues addressed in my recent book Understanding Consciousness (henceforth referred to as UC). A few of the commentaries elaborate on TA and do not require a response. John Kihlstrom for example gives an excellent review of the evidence for the causal effects of consciousness on body/brain, the explanandum of TA, and Todd Feinberg outlines an independently arrived at but similar understanding of consciousness/brain interactions to my own. Of necessity, the bulk of my response is reserved for those who challenge aspects of my analysis, seek clarification, or defend alternative analyses. Can reductive physicalism be defended? The causal interactions between consciousness and brain could be easily explained, at least in principle, if consciousness were nothing more than a state of the brain. But, in the Appendix to TA I have given some of my reasons for doubting that science will ever demonstrate human phenomenal consciousness (C) to be nothing more than a state of the brain (B). I accept the widely held view that for any given conscious experience there will be associated physical causes and correlates within the brain. However, causation and correlation are not ontological identity. Identity is symmetrical (If B=C, then C=B) and obeys Leibniz's law (if B=C, then all the properties of B must also be the properties of C and viceversa). Correlation is symmetrical (if B correlates with C, then C correlates with B) but it does not obey Leibniz's Law. Causation is neither symmetrical nor obeys Leibniz's Law. Why does this matter? Suppose that third-person science had established a perfect 1:1 correlation between a given experience C and its physical correlates B. Wouldn't that suffice to establish a reductive identity between them? No, because major differences between the first-person phenomenal properties of C and the third-person physical properties of B would remain.1 C and its o elate B ould of ou se e i ti atel elated. But a i ti ate elatio ship eed ot e a edu ti e ide tit . A o di g to dual-aspect theory, B and C are complementary aspects of mind-itself. This would explain both their perfect correlation and their phenomenal differences. So it would provide a better fit to the available facts. I defe e of a diffide t ph si alis Torrance argues that if C and B were identical, that would also explain their correlation a d gi e the p o le s i he e t i competing theories, asserting an identity relation seems reasonable, in the absence of a better alternative. Gi e its ette fit to the a aila le fa ts, I ould a gue that dual-aspect theory does provide a better alternative and that its so-called problems are not problems at all (see below). I suspect that, on reflection, Torrance would agree that if physicalism can only establish consciousness/brain identity by assuming it, then it is on very weak ground indeed. Can nonreductive physicalism be defended? Of the physicalist theories, those of the emergent variety are perhaps the most plausible. It is obvious that higher-order physical properties emerge from the brain's micro-operations. In a sense, conscious experiences also emerge from the brain (in the sense that brain states can be said to cause or correlate with conscious experiences). I nevertheless resist the view that conscious experiences are just higher-order physical states of the brain. Higher order physical states of the brain are likely to correlate with given conscious experiences, but this does not warrant a reduction of the experiences to their correlates for the reasons outlined 2 in the section above. Torrance suggests that it is a little unfair to tar the emergentists with the same brush as the reductionists. Emergentists accept that what emerges may be toto mundo distinct from the processes that have produced them. I agree, and I also agree that there is no problem about treating higher-order emergent properties of the brain as physical if, on commonly accepted criteria, they are physical (e.g. the electrical and magnetic fields detected by EEG and MEG). On the other hand, if, on commonly accepted criteria, conscious experiences would be categorised as mental as opposed to physical, then calli g the ph si al e o es a e e ela elli g e e ise. To gi e this e e ise ite, o e ould ha e to sho that all the p ope ties that that a e o all thought of as e tal (first-person properties) are in fact physical (third-person properties) otherwise one is si pl left ith all the p o le s of h hat it is like to e so ethi g should e e ge from or have a causal influence on the physical world. Torrance argues that a weak or wide form of physicalism might nevertheless be coherent and at the very least, tenable (in spite of there being no strong case for it). That may be so. But a physicalism that weak and wide would be empty. All the puzzles of consciousness would simply slip through its net. In defence, Torrance suggests that there a e othe easo s to do ith o tologi al economy, conceptual conservatism, causal closure, and so on, against introducing nonph si al p ope ties i to the u i e se. I a ept that o tologi al e o o si pli it is desirable, but it has to be balanced against sufficiency, and I would argue that ontological monism combined with epistemological dualism achieves that fine balance. I don't agree that conceptual conservatism should be the order of the day when we are faced with a theoretical orthodoxy about the nature of conscious experience that is so clearly at odds with our actual conscious experience. In any case, the explanatory system in UC does have causal closure as far as I can tell. Crucially, I am not i t odu i g o -physical properties into the u i e se. I a e el suggesti g a othe a to ake se se of the phe o e al properties that are observed to be there. Can nonreductive physicalism be defended against my three threats to the third-person causal status of consciousness? 1. We lack conscious knowledge of the details of the processes that we are supposed to consciously control. According to Van Gulick this does not trouble nonreductive physicalism. As he notes, we often need very little knowledge of a process and of its detailed workings in order to affect, control or initiate it. Use of a computer for example does not require one to know anything about the underlying structure of the operations that execute its commands in machine language. Yet the high level control that we exercise is surely conscious. I agree—and I have used a similar argument to defend my own dual-aspect analysis of causality in TA (p. 17). However, I think we need to be precise about the sense in which su h o s ious o t ol a e o s ious. Co t ol a e onscious in the sense that we are conscious of exercising control in this high level (global) way, and for everyday purposes this experience of being in control is veridical (when we think we have voluntary control, we usually do—see discussion of free will in TA). Controlled processing can also be conscious in the sense that it results in a conscious experience. The critical issue, however, is whether first-person conscious phenomenology actually controls or enters into physical processing, which seems to contravene the principle that the physical world is causally closed. 3 2. The problem of causal closure. If first-person experiences are invariably accompanied by disti t ph si al o elates, a d if the ph si al o ld is ausall losed, I do t see ho such experiences could exercise causal control—as the relevant control would already be e e ised thei ph si al o elates see the p o le of o e dete i atio aised i the commentary by Chrisley & Sloman . The o l es ape oute fo o edu ti e ph si alis is to argue that, one day, science will establish conscious experiences to be nothing more than their physical correlates. As I have argued in the Appendix of TA, however, third-person science is restricted to establishing the neural causes and correlates of experiences. Given that causes and correlates are not identities, this scientific route to establishing a reductive identity is blocked.2 3. Consciousness comes too late to affect the processes to which it most closely relates. Scientific claims for the causal efficacy of consciousness are typically based on contrastive analysis. Psychologists commonly contrast preconscious or nonconscious processing of a given type (e.g. preconscious visual processing of input) with conscious processing of the same type (e.g. visual processing where one becomes conscious of input) and then attribute any functional differences between these to the operation of consciousness. In Velmans (1991) I pointed out the fallacy of such attributions. Conscious experiences are a consequence of sophisticated, focal-attentive processing and without focal-attentive processing many forms of complex, novel functioning would not occur. However, the experiences themselves emerge too late to affect that processing. Van Gulick asks But h should this impugn the commonly accepted causal status of consciousness? Neither folk psychology nor any scientific model of consciousness of which I know supposes that experiences produce the very processing from which they themselves result. This isses my point. Once it is pointed out that consciousness results from a given process, of course no sensible person would claim it to have a causal role in that process. However, as far as I know, prior to my 1991 BBS target article, no one had pointed this out, claims for the causal efficacy of consciousness based solely on nonconscious/conscious contrasts were legion, and they continue, unabated to this day (see e.g. Baars, Banks & Newman, 2002). I accept, of course, that consciousness might in principle enter into processing that follows its emergence. However, this proposal still has to surmount the problem that the physical world is causally closed (see TA, Note 17 - and discussion above). Points of clarification on my own theory Van Gulick asks whether my own view is just a variant of a form of nonreductive physicalism that accepts explanatory pluralism. This would allow higher-level forms of mental organisation to have properties that are best described at that level rather than in the more basic terms of physics, without doubting that such properties are ultimately physical. This applies, for example, to economics. No one is worried by a money/matter problem or seriously advocates money/matter dualism. So why could the same not be true of mind? Van Gulick also points out that my epistemology in TA is presented as first- versus thirdperson dualism rather than pluralism although he notes that this may well be more a matter of exposition rather than substantive disagreement. 4 As it happens, these issues interconnect. Rather than contrasting epistemological dualism with epistemological pluralism, in my own work I combine these. That is, I support the view that there are many forms and levels of explanation within both first- and third-person accounts. As Van Gulick notes, pluralism is commonplace in third-person science, with welldefined hierarchies defined by the size and level of organisation of the phenomena, typically ranging from microphysical, macrophysical, chemical, biological, neurophysiological, cognitive/functional, and social levels of organisation. Nonreductive physicalism usually identifies conscious experience with just one level of this hierarchy, typically the cognitive/functional level that, in turn, supervenes on the brain's neurophysiology. In my view this is an oversimplification. Like the forms of material organisation that they accompany, first-person experiences can be described at different levels and may have an ontology at different levels. Some experiences appear to be socially determined, being, in part, social constructions grounded in culture and history (e.g. what it is like to be the Prince of Wales). Others (such as empathy) are quintessentially interpersonal, requiring the presence of at least one other human being (see readings in Thomson, 2001 Between Ourselves). Yet others, such as visual and auditory percepts appear to be largely individual, resulting from the binding of sensory features within an integrated human brain. Under appropriately controlled conditions these features can be further decomposed into the minimally discriminable phenomenal differences studied by psychophysics and so on. 3 It is important to note that so- alled o edu ti e ph si alis is reductive in that it claims conscious experiences to be nothing more than a form of higher order material organisation or cognitive functioning. While dual-aspect theory accepts that every distinct experience has a distinct set of third-person physical and/or functional correlates (at social, personal or subpersonal levels of organisation) it resists the physicalist suggestion that such conscious experiences are reducible to their correlates at any of these levels. Rather, first person accounts of experience and third person accounts of accompanying physical functioning remain complementary and mutually irreducible, whatever the level of organisation. This brings us to Van Gulick's Point 2. Do I equate the mental perspective with the firstperson perspective? No. Like nonreductive physicalism, I treat the first person perspective(s) as a subset of a larger set of mental perspectives, some of which are entirely third person in nature, for example, those aspects of mental functioning described in 4 cognitive psychological accounts of the mind. Unlike nonreductive physicalism, however, I argue that mental processes that have a conscious phenomenology cannot be exhaustively described in third person terms. While it is possible to describe what people do or how their brains function when they have beliefs, desires, etc., in third-person terms, without reference to their first-person perspective it is not possible to describe what they experience. I have given some of my initial reasons for the irreducibility of first- to thirdperson accounts in the Appendix to TA. As Van Gulick does not take issue with this preliminary analysis I will not offer a deeper defence of it here. Interested readers will find a far more extensive analysis in chapters 3, 4 and 5 of UC (see also my debate with Dan Dennett in Velmans, 2001). This brings us conveniently to Van Gulick's point 3. As he notes, I share the physicalist commitment to ontological monism, but my dual-aspect view takes the ur reality (the nature of mind in this case) to be neither physical nor mental. Why? Precisely because it 5 has both of these mutually irreducible, first- and third-person aspects. Viewed from the outside, the operations of ur mind appear to be operations of brain. Viewed from a firstperson perspective, the operations of ur mind appear to be conscious experiences. Which is it really? If one assumes (as I do) that neither perspective is necessarily illusory or deluded, then the nature of ur mind must support both the views that we have of it. Given this, its nature is better des i ed as ps hoph si al tha ph si al. This also addresses Torrance's suggestion that my position is not really all that different from nonreductive physicalism. He asks, Does t o is i pl u it ? “o a e ou ot saying that the neuroscientist s thi d pe so fa ts a d the su je ti e fi st-person facts are t o e uall eal pa ts of a si gle u it ? But the , if o e side of this u it is ph si al, ust t the othe side also e ph si al o it s ot a u it ? He the guesses o e tl that, Pe haps Vel a s a s e to this is that eithe the thi d-person physical facts nor the firstperson subjective facts are ultimately real, and that the underlying bedrock of reality is neither the one nor the other. (I guess this is implied by his calling it a dual-aspe t theo . Viewing the mind-itself as psychophysical rather than physical is more than a simple relabelling exercise. What does this form of dual-aspect monism buy us? As I have argued in UC, If consciousness and its physical correlates are actually complementary aspects of a ps hoph si al i d, e a lose the e pla ato gap in a way that unifies consciousness and brain while preserving the ontological status of both. It also provides a simple way of making sense of all four forms of physical (P) and mental (M) causal i te a tio . Ope atio s of i d ie ed f o a pu el e te al o se e s pe spe ti e (P P), operations of mind viewed from a purely first-person perspective (M M), and mixed-perspective accounts involving perspectival switching (P M; M P) can be understood as different views (or a mix of views) of a single, psychophysical information process, developing over time. In providing a common psychophysical ground for brain a d e pe ie e, su h a p o ess also p o ides the issi g li k e ui ed to e plai ps hoso ati effe ts. (UC, p 251) (see also TA page 14)5 Escape from the problem of causal closure. In Van Gulick's o ds If the physical factors revealed from the third person perspective give a complete causal explanation of physical events and nothing nonphysical can have a causal impact on the physical, then there does not seem to be any room for other factors viewed from an alternative perspective to act as causes of physical events. I ag ee. But e a e ot i te ested here in purely physical events. We are interested in the nature of mind, and according to the above, the nature of mind is psychophysical. U like o edu ti e ph si alis this a al sis of i d a d M P causation is genuinely nonreductive. And it is this that makes it immune to Kim's (1999) point that, if the physical world is causally closed, either the mental reduces to the physical, or it must be epiphe o e al. U like o edu ti e ph si alis I do ot lai that fi st-person experiences somehow enter into third-person physical functioning, so I do not need to reduce these experiences to physical events to make good that claim. Within dual-aspect theory there is a more intuitively plausible option. If the mind is genuinely psychophysical, then an entirely third-person physical view of it gives only a partial view of both its nature and its causal operations. Brain states are genuine phenomena (manifestations of ur mind), 6 viewable from a third-person perspective, but conscious experiences are also genuine phenomena (manifestations of ur mind) viewable from a first-person perspective. Descriptions of brain states can be used to give a detailed account of the operations of mind in terms of its physical manifestations. Descriptions of first-person experience can be used to give an account of the operations of mind in terms of its conscious manifestations. For scientific purposes, third-person accounts are more useful. For everyday purposes, firstperson accounts are often more useful. Both are required for an account of mind to be complete.6 In what sense does this complementary perspectives account advance our understanding of the hard pro le s of o s ious ess? In UC and prior work I have argued that some of the problems of consciousness require conceptual advance, some require empirical advance, and some require both. Empirical uestio s i lude, What a e the e essa a d suffi ie t o ditio s fo o s ious ess i the hu a ai ? a d What a e the eu al o elates of o s ious ess? Questions such as What is o s ious ess? What is the fu tio of o s ious ess? a d Ho a o e ake se se of the ausal i te a tio s of o s ious ess a d ai ? appea to e la gel conceptual. Why? Because the considerable evidence that one can already bring to bear on these questions somehow fails to address them. Each and every one of us has a vast ese oi of o s ious e pe ie e. Gathe i g o e of it o t la if hat o s ious ess is. E te si e o t asti e a al ses of o s ious e sus o o s ious p o essi g ha e already been carried out in psychological science. These illustrate functional differences between processes that either are, or are not accompanied by phenomenal consciousness. But su h o t asts do t e eal hat the o s ious phenomenology itself does (see TA). Nor does the massive evidence for mind/body interactions reveal how to make sense of the causal interactions of consciousness and brain. It is the opacity of these questions to further data gathe i g that akes the ha d. The p ese t TA deals o l ith the last of these ha d p o le s I deal ith the othe problems and with how they all interconnect in UC). According to Gray, however, these problems are tangential to the real hard problem. Rather, the Ha d P o lem can be stripped down to just two questions: how does the brain create qualia; and how does the ai i spe t the ? It ill e appa e t that I do ot e ti el ag ee. These t o uestio s are two of many. As it happens, they have third-person aspects that are fully amenable to e pi i al esea h. O e p ope a s e to the uestio Ho does the ai p odu e ualia? ould e to spe if the necessary and sufficient physical conditions in the brain for the appearance of conscious qualia. This can be investigated by contrasting physical conditions that are necessary and sufficient for the appearance of qualia with those that are not—a standard method in science. Viewed in third-pe so te s, ho the ai i spe ts ualia a e e plai ed i te s of ho it inspects representations at the focus of atte tio , ake the a aila le fo epo t , a d so o . One might object, of course, that such third-person accounts don't answer the right question. The hard problem is not how one part of the brain might inspect and report on information in another part of the brain. It is how a physical ai ould i spe t a fi stperson conscious experience! But this is precisely the question that I do address! 7 Ontological monism combined with epistemological dualism makes it clear that one can give a pu e thi d pe so a ou t of ai fu tio i g i te s of ho su s ste s i the ai i spe t ep ese tatio s at the fo us of atte tio . O e a also gi e a pu e fi st-person a ou t of hat is goi g o i te s of the way that I, a conscious being, can inspect my o o s ious e pe ie e . A a ou t of ho the ai i spe ts its o s ious e pe ie e a the e see to e a i ed-perspective account, involving perspectival s it hi g see TA . As Gray otes, the only satisfying explanation will be one that shows ho o s ious ess is li ked to the s ie tifi a ou t that applies to the est of that o ld. In broad terms, that is what this analysis achieves. Gray o je ts that, The sta da d ite io fo hether or not a proposed theory forms part of science is potential falsifiability by empirical observation. I cannot think of any such test of Vel a s odel, o has he p oposed a hi self. The sa e is t ue, so fa as I k o , of all other versions of dual-aspect theory, including for example Chalmers' (1996) recent attempt to seek a common basis for the physical and conscious realms in an underlying stuff of i fo atio a o e Vel a s also akes, i his se tio o the eu al o elates of conscious expe ie e . Thus, Vel a s p oposed solutio to the Ha d P o le is pu el philosophi al, hi h is to sa , pu el e al. It pu po ts to tell us hat e eall ea when we say things, respectively, from first-and third-person points of view. We need to o e e o d this. pp. -50) Rao also makes a similar complaint, when he suggests that I t to esol e o tologi al issues edu i g the to episte ologi al o es. p. 64) I accept the point that some aspects of my analysis have to do with how to understand hat e eall ea he e sa thi gs, espe ti el , f o fi st-and third-person points of ie , a el a ou t of pe spe ti al s it hi g, a d i ed-perspective explanations. However the ontological monism, combined with epistemological dualism that underpins this analysis is not just linguistic philosophy. It is a claim about the basic ontology of mind, its manifestations, and about how we can know its nature and its manifestations. For example, the proposal that first- and third-person perspectives of the mind are complementary and mutually irreducible is a claim about mind and how we can know it in the same sense that wave-particle complementarity is a claim about the nature of light, or electromagnetic energy is a claim about the unified nature of electricity and magnetism. I also accept that my global analysis of how to make sense of the causal relations of consciousness and brain is not a theory about the details of how information encoded in the brain is mapped into conscious phenomenology. However such details can, in principle, be settled by empirical research, which makes them so- alled eas p o le s athe tha ha d o es. To ake se se of the ha d p o le s e eed to think about them in a different way (perhaps in the way that I suggest). But that does not make my entire analysis u falsifia le, a d pu el e al a d philosophi al. 7 A quick revisiting of my case for dualaspect theory and my critique of alternative theories will confirm that they are tightly linked to falsifiable, experimental and clinical evidence—to evidence of mind/body interactions (see Kihlstrom), to evidence that the physical world is causally closed, to evidence that phenomenal consciousness comes too late to affect the processes to which it most closely relates (Velmans, 1991), to evidence of preconscious and unconscious processing, and so on. Crucially, unlike the variants of physicalism and functionalism defended by Torrance, 8 Van Gulick, and Chrisley & Sloman, the dual-aspect theory developed in TA also conforms closely to the evidence of first-person experience. It is instructive to dwell on this last point. Although the dual-aspect analysis in TA, and the Reflexive Monism that underpins it in UC are broad theories about how to make sense of the relation of consciousness to brain rather than theories about the neurophenomenological details, they are first and foremost empirical theories that try to make sense of the combined third- and first-person evidence. If there were convincing thirdor first-person evidence that challenges some aspect of these theories, or some clear flaw in how the analyses connect to the data, then I would modify or abandon the theories. Many experimental and theoretical developments could challenge the details of my analysis, for example current attempts to demonstrate that a cognitive unconscious does not exist Pe u het & Vi te , , o that ualia do ot e ist see de ate ith De ett i Velmans, 2001), or that the neural correlates of consciousness are not representational states that encode identical information (Chrisley & Sloman—see below), or that consciousness is actually a mental field that influences the activities of brain (Libet, in press). I ould also a a do o ple e ta pe spe ti es a alysis if our everyday insights into the operations of our own minds based on our first-person experiences turned out to be largely wrong. Compare this with physicalism. Physicalism draws its scientific respectability from its a esake ph si s . Ho e e physicalism is a philosophical thesis about the ontological nature of conscious experience, not a field of science. Its claim that first-person phenomenology reduces, without remainder, to states of the brain has no real evidence in its favour (neural causes and correlates are not identities), and massive evidence to the contrary (conscious phenomenology does not resemble brain states). This makes it basically a faith in the all-encompassing nature of third-person science—a commitment to a worldview that is immune to falsifying evidence. If one is looking for an unfalsifiable theory, here it is. How conscious experiences relate to their physical/functional correlates At present, we know little about the physical nature of the correlates of conscious experiences. Nevertheless, in UC and TA I suggest that there are three plausible, functional constraints imposed by the phenomenology of consciousness itself. Normal human conscious experiences are representational (phenomenal consciousness is always of something). Given this, it is reasonable to assume that the neural correlates of such experiences are also representational states. For a given physical state to be the correlate of a given experience it is also plausible to assume that it represents the same thing (otherwise it would not be the correlate of that experience). Finally, for a physical state to be the o elate of a gi e e pe ie e, it is easo a le to suppose that it has the sa e g ai . That is, for every discriminable attribute of experience there will be a distinct, correlated, physical/functional state. As each experience and its physical correlate represents the same thing it follows that each experience and its physical correlate encodes the same information about that thing. That is, they are representations with the same information structure.8 I also point out that different representational systems employing different formats can encode identical information without themselves being identical. Neural 9 correlates, for example, might function as representations (encoding identical information to that displa ed i thei o elated phe o e olog ithout i o i g that o s ious phenomenology in any obvious physical sense. While such correlates might be iconic, they could also be propositional, feature sets, prototypes, procedural, localised, distributed, static, dynamic or whatever. The operations on them might also be formal and computational, or more like the patterns of shifting weights and probabilities that determine the activation patterns in neural networks (TA, note 10). 9 Given that I do give a supporting case for this in TA (and a far more detailed case in UC pages 236-251) it is hard to understand Chrisley & Sloman's o te tio that I o e without argument, from the representational nature of experiences to the existence of neural correlates of these experiences which have the same representational content as these e pe ie es. No is it eas to ake se se of thei lai that I a eithe aki g a rather strong reductionist assumption, or (worse) postulating a dubious causal connection et ee the st u tu e of e pe ie e a d the st u tu e of eu al states . As I ha e oted, different representational systems can encode identical information without the systems reducing to each other—and the relation between experiences and their physical correlates is, by definition, correlation not causation. Would the discovery of psychophysical correlations be scientifically useful? As noted above, even perfect 1:1 correlations between conscious states and physical states would not establish their ontological identity. It is also well accepted in science that correlation does not establish causation. Consequently, even exact neurophenomenological laws that chart the way that given physical correlates map onto given conscious experiences would not be causal laws. If such bridging laws could be found they might nevertheless document invariant, empirical relationships in a precise way—and few, I suspect, would doubt that this would be a major scientific advance. Rakover, however, disagrees. A o di g to hi , o elatio al la s a e ot atu al la s a d a ot fulfil the requirements of measurement that are accepted in science. Consequently he thinks that neurophenomenological laws cannot be used to make sense of the causal relationships between consciousness and brain. In assessing how Rakover’s commentary relates to my TA it is important to first note that he does not actually address the detailed account that I have given of how to make sense of the causal relationships of consciousness and brain, nor of the way that potential neurophenomenological laws might fit into such an account. However he does offer a critique of the scientific status of neurophenomenological laws as such, and of the use of i fo atio as a u it of easu e e t i ps holog . As these a e i po ta t ele e ts of my analysis I will confine my reply to these relevant aspects of his critique. Second, although Rakover gives the misleading impression at the beginning of his commentary that my use of neurophenomenological laws is out of step with psychological practice in that it does not o fo to ules of the ga e that a e a epted the atu al s ie es and cognitive ps holog p. ), he goes on to admit at the end of his commentary that my use of such correlational relationships is entirely conventional within psychology and that his real target is psychology! As he concludes on page 57, his iti ue ould also e di e ted at 10 psychology at large. In comparison with research in the natural sciences, psychological esea h is li ited a d does ot p og ess like ph si s see ‘ako e , . What are these supposed limitations on psychological research? According to Rakover, neurophenomenological laws do ot fulfil the e ui e e t fo the u it e ui ale fou d in natural laws such as Newton's law of gravity, where the units of measurement found on both sides of the equation S = 1/2GT2 can be shown to be equivalent. Let us suppose, for example, that neuropsychology discovers the exact neural correlates of different subjective aspects of pain phenomenology and manages to express its findings in neurophenomenological laws. In such cases, Rakover asks, Ca it e sho that the combination of the units of measurement on the right-hand side of the pain equation is identical to the combination of the units on the left-hand side? To the best of my knowledge the a s e is o. p ) I agree. But such an absence of unit equivalency provides yet another argument against reductive physicalism. It has nothing to do with whether or not there are distinct physical/functional correlates of distinct pain experiences, or with whether or not it is possible to chart such relationships precisely in the form of nonreductive eu ophe o e ologi al la s that do ot e ui e u it e ui ale . But ould the a se e of u it e ui ale ake eu ophe o e ologi al la s unscientific? Consider Rakover's doubts about studies of pain phenomenology. Pain is often presented as a paradigm case of a private, subjective, mental event within philosophy of mind. There are many ways to measure the subjective experience of pain10, but at the present time o alid o je ti e easu e of pai e pe ie e i te s of a ph siologi al i de e ists. In spite of this, over the period 1960 to 2002, the Medline database lists around 200,000 publications on pain and its alleviation, making it a heavily investigated area of medicine. According to Rakover, such studies are restricted by the absence of fu da e tal easu e e t u its of the ki d that o tai , sa , fo the easu e e t of le gth, hi h sustain properties such as transitivity and additivity. While this is true, it is hardly news to anyone trained in psychological research, where it is taken for granted that whenever numbers are assigned to psychological variables these must be scaled in a way that is appropriate to those variables (reaction time and error rate merit a ratio scale, subjective judgements of magnitude generally merit an ordinal scale, categorical judgements a nominal scale, and so on). Once an appropriate scale is assigned, numbers derived from measurements of behaviour or subjective judgements can be subjected to appropriate statistical analyses, and the results interpreted as supporting hypotheses (or not) in the normal way.11 It is true that few relationships between physical and psychological variables have been fou d to e suffi ie tl ge e al a d o de l to e it the te la a d e e these do ot satisf u it e ui ale . Pe haps the est e a ple is “te e s po e la J = kIx where J is the judged intensity of a stimulus (e.g. its brightness or loudness), k is a scaling constant, I is the physical intensity (e.g. specified in lumens or decibels), and x is a constant whose value depends on the modality of the judged stimulus (e.g. for judged loudness, x=0.3). “te e s la charts how variations in the physical stimuli are translated into judged changes in the way those sti uli a e e pe ie ed. Co se ue tl it is o elatio al i p e isel the a that Rakover des i es. Does this ea that “te e s la is u s ie tifi ? No. The e a e ou tless examples in science where Nature does not fit into the neat conceptual boxes that we have 11 prepared for her, and the psychological and biological sciences have long abandoned the view that the only relationships of scientific interest are fundamental causal laws of the kind found in physics. Functional models in cognitive psychology and compositional accounts of the structure of iologi al s ste s a e o ious ases i poi t. I ps hoph si s, “te e s power law may not satisfy unit equivalency, but it nevertheless expresses empirically verifiable relationships between physical dimensions of stimuli and subjective judgements about those stimuli in a precise, systematic way, and it is in that sense unquestionably scientific. Given this, it is reasonable to hope that in some future neuroscience it may be possible to develop neurophenomenological laws with equivalent precision and generality. Rakover also claims that information cannot be a unit of psychological measurement. But again, few psychologists would agree. It is true that, following George Miller's (1956) seminal paper The magical number 7 ± 2, psychologist have long accepted that human mental p o essi g is ofte too fle i le a d a ied to e o puta le i its i the p e ise “ha o sense. Nonetheless the psychological use of concepts derived from information theory and/or the more general principles of information processing developed within electrical engineering is ubiquitous—to the point that, in cognitive psychology, mental processing is habitually referred to as human information processing. In any case, my own use of the terms i fo atio a d i fo atio st u tu e elate to a fai l p e ise use of these te s that is applicable in psychophysics, for example in the study of difference limens (minimal discriminable differences). Such studies document whether or not physically measurable differences in stimuli are translated or not (by sensory/perceptual processes) into consciously perceived differences, that is whether or not information about physical differences is translated into detectable changes in phenomenology.12 In the same way it is possible to study whether or not physical/functional differences in neural representations of stimuli are translated into detectable changes in phenomenology. Physical/functional changes in neural representational states that are t a slated a e said to e of the sa e g ai as the conscious phenomenology and to mirror its information structure. Rakover doubts that it would be possible to identify such information bearing states, as one cannot remove one's dependence on subjective reports of what is or is not experienced. I agree that one cannot remove subjective reports. However, the combination of subjective reports with triangulating third-person observations of neural states is standard practice in neuropsychology. Investigation of the neural correlates of consciousness is technically difficult, but the field of investigation is already very large (cf Metzinger, 2000). Rather than being questionable science, it is unquestionably normal science. Analogies The ways in which different conscious experiences relate to their physical correlates have to be understood in their own terms. Some properties of these relationships appear to resemble ones that are already well understood in natural science, but, as far as one can tell, no other purely physical system provides an exact homology. Crucially, the relations of experiences to their physical correlates have to be understood in terms of how certain phenomena (the experiences) viewed from a first-person perspective relate to other phenomena (the correlated brain states) viewed from a third-person perspective. By contrast, all the properties of physical systems (conventionally understood) can be viewed from a third-person perspective. 12 Videotapes and TV screens. Sometimes, however, analogies can help. For example, to understand how experiences and their physical correlates might encode identical information without themselves being identical it is useful to know that such a dissociation between representations and representing systems are commonplace in technology—as in e a ple of the pla Ha let e oded o ideotape o displa ed o a s ee . Gi e limited intent, it is hard to understand Chrisley & Sloman's claim that this analogy isfi es. As the o e tl ote, this is ot a o tologi al edu tio . However, a o di g to the , it is a episte ologi al o e , a d the the go o to lai that, episte ologi al dualis is the o l thi g sepa ati g Vel a s f o the ph si alist positio s he eje ts. But ho a this e? Videotapes and TV screens encode information in entirely different formats. Even when they encode information about the same thing, they do so in two entirely different ways— which is broadly analogous to knowing about one thing in two different ways. So in what se se is this a episte ologi al edu tio ? Ad ittedl , the e is o e k o , the atu e of mind, with two (material and phenomenal) aspects, by which it can be known. But, given that I suggest the atu e of i d to e ps hoph si al, i hat se se is this 13 ph si alist ? Electricity and magnetism. The same information can be formatted differently, depending on the characteristics of the representing system. If one can specify the different ways that given information is formatted, then it should be possible, in principle, to specify how those different formats map onto each other. In TA and UC I suggest that, in some future neuropsychology it might be possible to specify how the phenomenology of given consciousness experiences map onto to their physical correlates in this way. This might provide a dual-aspect account of the nature of mind in which the relationships between its physical and phenomenal aspects were specified precisely, perhaps with the precision that electrical current in a wire can be related to its surrounding magnetic field.14 Chrisley & Sloman confusingly suggests that the duality that I have in mind with the ele t o ag etis a alog , is o e of aspe ts, ot of o tologi al ha a te . What I a tuall suggest is that the phenomenal and physical aspects of mind specify its (psychophysical) ontological character.15 E e o e o fusi gl the go o to ite, … the a alog does t work: electricity and magnetism are not simply two ways of thinking about the same phenomenon, but two different physical phenomena that can be related to each other athe ati all . Gi e that I e e suggest that ele t i it a d ag etis a e si pl t o ways of thinking about electromagnetism (rather than genuine aspects), nor that physical and phenomenal aspects of mind are simply two ways of thinking about mind (rather than genuine aspects) the relevance of this comment to my analysis is hard to understand. They then add to the confusion by going on to write, I o t ast, a d u iall , Vel a s lai s that the difference between first and third person ways of thinking of psychophysical stuff is e el that of diffe e tl fo atted a s of ep ese ti g the sa e i fo atio . I lai nothing of the sort. As noted above, first- and third-person (phenomenal and physical) aspects of mind a e ot e el diffe e t a s of thi ki g a out it. Bei g ge ui e phenomenal and physical aspects (or manifestations) of mind, they can in principle encode the same information in different phenomenal and physical formats. Chrisley & Sloman go 13 on to note that the ele t i al phe o e o is ot just a aspe t, a a of fo atti g the same information as that represented by the magnetic way of looking at the situation. There are situations where only the electrical description applies, and other situations he e o l the ag eti des iptio applies. I ag ee—although this again has nothing to do with my analysis of dual-aspect monism or my use of the electricity/magnetism analogy.16 The go o to o lude that, P i a fa ie, this suggests that the e a e t o distinct phenomena involved; to argue that there is actually only one, root phenomenon will e ui e fu the o k f o Vel a s. He e I disag ee. Ele t i it a d ag etis a e i deed distinct phenomena, but the view that they are both manifestations of only one root phenomenon (electromagnetism) is received wisdom in physics. It requires no further work from me.17 Wave-particle complementarity. In TA note 13 and UC I note that my dual-aspect analysis of mind also has some interesting resemblances to wave-particle complementarity in quantum mechanics—although, once again, the analogy is far from exact. Quanta either appear to behave as electromagnetic waves or as particles depending on the observation arrangements. And it does not make sense to claim that electromagnetic waves really are particles (or vice versa). A complete understanding of quanta requires both complementary descriptions. First- and third-person observations of mind also depend on very different observational arrangements, so that may help to explain why, from a first-person perspective it takes the form of conscious phenomenology, whereas viewed from the outside it appears to be a brain. Like wave-particle accounts in quantum mechanics, phenomenal and physical accounts of the mind's operations appear to be complementary and mutually irreducible. A complete account of mind requires both. Note that these distinguishing features of dual-aspect monism contrast sharply with competing analyses of the experience/brain state relationship. Substance dualists maintain that e pe ie es a d o elated ai states a e e ti el diffe e t su sta es o e tities , idealists a gue that all ph si al e tities i ludi g ai states a e eall fo s of mind or consciousness (Rao), and physicalists argue that experiences are nothing more than states of the brain (Torrance, Van Gulick, Chrisley & Sloman). All these positions have well known problems. For example, dualism splits the universe in a way that makes it difficult to get it together again, idealism does not cope well with the apparent, autonomous existence of the material world, and physicalism does not cope well with the phenomenology of conscious experience. I have argued that dual-aspect monism allows one to accommodate first- and third-person evidence in a more natural way that avoids such problems. While the case for this above (and in Velmans, 1991, UC and TA) does not rely in any way on analogies from other branches of science, the parallel with wave-particle complementarity in quantum mechanics is suggestive. However, according to Chrisley & Sloman, this a alog is e e o se —although they take issue ot ith e, ut ith the fou de s of ua tu e ha i s. The ite, Mo e a d more physicists and philosophers take the appeal to complementarity as a reductio ad absurdum of particular ontological positions in quantum mechanics. They do not deny the veracity of the data that have led some to conclude that quanta have both wave and particle aspects; but they do deny that the paradox of complementarity is a satisfying way of accounting for that data. There are other, less paradoxical and thus more satisfying metaphysical pictures on offer (e.g. Bohm, 1952; Hiley and Pylkkänen, 2001). To say that 14 your metaphysics of mind is akin to the wave/particle complementarity metaphysics of ua ta is just a othe a of sa i g that ou do t ha e a satisf i g etaph si s, a d hoose i stead to li e ith the pa ado es. I thi k that is ei g athe u fai to ou colleagues in physics. The majority of physicists are more concerned with whether the mathematics of QM accounts for the data, and they think of (exclusive) complementarity as a current, best description of the empirical findings, imposed by the limitations of easu e e t, athe tha a reductio ad absurdum of pa ti ula o tologi al positio s. No is there any emerging consensus about what would be a satisfying metaphysics. As it happens, I share Chrisley & “lo a ’s interest in more classical accounts of QM findings (in spite of this being a minority view in physics). According to Bohm and his collaborators, wave-like and particle-like behaviour are manifestations of a unified, grounding reality Boh ofte efe s to this as a i pli ate o de just as I ha e lai ed e pe ie es a d their physical correlates to be dual-aspects of a unified, psychophysical mind. So adopting a classical metaphysics in QM (in the way that Chrisley & Sloman suggest) would make the analogy with dual-aspect monism even closer! In sum, let me stress again that analogies have their purposes, but they are not homologies. The analogies that I have used illustrate how phenomenal and physical representational systems might format the same information in different ways, and how phenomenal and physical aspects of mind might be tightly bound to each other without reducing to each other. But I do not claim consciousness to be literally a picture on a TV screen, a magnetic field, or a wave-like QM phenomenon (to claim all three simultaneously would in any case be absurd). The relation of any given conscious experience to its physical correlates has to be understood in its own terms. A re-examination of what we take for granted. What has ontological primacy—consciousness, or the physical world? In current Western philosophy and science the existence of the physical world is generally taken for granted, while the existence of consciousness is thought to be somewhat mysterious. The physical o ld is also ge e all assu ed to e the p i a ealit o hi h othe e e ge t fo ms of existence such as mind and consciousness depend. Chrisley & Sloman for example, take it for granted that the physical/experiential relationship is asymmetrical. Physical states can exist without accompanying experiences (e.g. in the form of preconscious brain states)—but conscious experiences cannot exist without accompanying physical states. As they note, The o l a to i pose s et ould e to assu e as othe s ha e ee fo ed to do, e.g. Chalmers, 1996) that whenever there is a physical phenomenon, there is some experiential phenomenon, however slight or imperceptible or implausible, accompanying it. Pa ps his th eate s. It is instructive to note however that such opinions about what has ontological primacy and hat o stitutes a th eat to ight thi ki g a e ot u i e sal. As Rao points out, very different views about the ontological status and distribution of consciousness and mind dominate in philosophical traditions that have developed in the East. In these traditions, the irreducibility of consciousness to brain states is taken for granted and consciousness, not the physical world, is thought to be primary. In some Indian traditions for example, the physical world is thought to be a projection of consciousness constructed by the mind. 15 How is it possible that thinkers in the West and the East have come to such very different conclusions? Note that the ontological primacy of either consciousness or the physical o ld is ot o ious f o the i ediate, e pi i al e ide e of ou se ses fo the si ple reason that, in everyday life, conscious experience and what we normally think of as the ph si al o ld co-arise. That is to say, what we normally think of as the physical world just is the 3D phenomenal world that we experience.18 However, Western and Eastern thinkers have traditionally taken a very different interest in what is experienced. Western thi d-pe so s ie e has t aditio all ee i te ested i e pe ie e as a ea s to a e d, namely the nature, control and transformation of the entities and events that such experiences represent (what they are experiences of) and has developed investigative ethods a d te h ologies app op iate to these i te ests. B o t ast, Easte fi st-pe so philosophy and science has traditionally been interested in the nature, control and transformation of the experiences themselves, and has developed methods appropriate to these aims. I suggest that these different foci of interest and accompanying methodologies partly explain East-West differences of opinion about what has ontological primacy. It is ot altogethe su p isi g that if o e s thi d-person investigative attention is entirely fo used o the ate ial e tities a d e e ts that o e s e pe ie es ep ese t, o e ight conclude their fundamental nature to be entirely material. Many external entities and events appear to exist whether they are experienced or not, thereby supporting their ontological primacy and a form of physical realism. In the human brain some processes appear to be accompanied by consciousness while others appear to be preconscious, unconscious or non-conscious, suggesting a physical/experience asymmetry. Viewed from the outside, the material forms of entities and events are evident, but not any accompanying experience, e e i othe hu a ei gs the p o le of othe i ds . Consequently panpsychism looks dubious. O the othe ha d, if o e s fi st-person investigative attention is focused in ever finer ways on conscious experience itself it is not surprising that one might conclude its fundamental atu e to e a efi ed fo of o s ious ess t aditio all a pu e , o te tless o s ious ess . Co s ious e pe ie e is i a ase i ediatel gi e a d is episte i all primary in the sense that it provides the foundation for the acquisition of all empirical k o ledge. I deed, hat e o all thi k of as the ph si al o ld just is the D phenomenal world that forms part of everyday conscious experience (see above). Conversely, without conscious experience this phenomenal physical world would not exist (a form of idealism), thereby providing grounds for the Eastern view that consciousness has ontological primacy. Which view is correct? It is not possible to attempt a full analysis in a few lines. However, in UC and TA I develop a dual-aspect, reflexive monism that treads a careful path between taking either a first- or third-person approach to be more privileged or fundamental. Rather, these perspectives are complementary and mutually irreducible. For example, in Velmans (1990a) and UC chapter 7 I suggest that Eastern idealism and Western realism may both be true although they are true about different things. Idealism may be said to apply to the observer-dependent existence of the phenomenal world while realism applies to the observer-independent existence of the entities and events (things themselves) that experienced phenomena represent. Under normal conditions, neither a first- nor a thirdpe so pe spe ti e p o ides a ie f o o he e, that is a ie of the thi g-itself as it is in-itself, even if the aspect of the thing-itself under scrutiny is the human mind. Conversely, 16 both investigative routes can lead to deeper knowledge. Third-person science provides a deeper knowledge of the material world, understood in a third-person way. First-person i estigatio s of o s ious ess p o ide a deepe k o ledge of o e s o i d, u de stood in a first-person way. My route to this position is an entirely conventional Western one, relying on the normal triangulation of scientific evidence, everyday experience, common sense and theory. Nevertheless, once the implications of this position are fully worked out (in terms of what consciousness is and does, and how it relates to the brain and the physical world) the Reflexive Monism that results takes one a long way from current Western materialism. I conclude for example that Hu a i ds, odies a d ai s a e e edded i a fa g eate u i e se. I di idual conscious representations are perspectival. That is, the precise manner in which entities, events and processes are translated into experiences depends on the location in space and time of a given observer, and the exact mix of perceptual, cognitive, affective, social, cultural and historical influences which enter into the o st u tio of a gi e experience. In this sense, each conscious construction is private, subjective, and unique. Taken together, the contents of consciousness provide a view of the wider universe, giving it the appearance of a 3D phenomenal world. This results from a reflexive interaction of entities, events and processes with our perceptual and cognitive systems that, in turn, represent those entities, events and processes. However, conscious representations are not the thing-itself. In this vision, there is one universe (the thingitself), with relatively differentiated parts in the form of conscious beings like ourselves, each with a unique, conscious view of the larger universe of which it is a part. In so far as we are parts of the universe that, in turn, experience the larger universe, we participate i a efle i e p o ess he e the u i e se e pe ie es itself. UC, p. 233). Later, I add, In this sense, we participate in a process whereby the universe observes itself—and the universe becomes both the subject and object of experience. Consciousness and matter are intertwined in mind. Through the evolution of matter, consciousness is given form. And through consciousness, the material universe is real-ized. UC, p. 280). It is not possible to summarize the full implications of reflexive monism in a few lines, let alone the case supporting it. However, as Rao notes, my route appears to travel from West to East. His only complaint is that I have not traveled far enough! While I do not have space to deal with how UC relates to various Eastern philosophies in any detail, Rao’s comments provide a welcome opportunity to assess the internal coherence of TA (and UC) from a very different perspective, and it is instructive to address his main points.19 From West to East? A o pa iso of Easte a d Weste ie s of o s ious ess a d i d has to sta t with a clarification of terms, for the simple reason that in the West and the East the terms o s ious ess a d i d a e ha ituall used i different ways. As Rao notes, I largely o fi e use of the te o s ious ess to phenomenal consciousness—the everyday experience of the external world, the body, and inner experiences (such as thoughts, 17 feelings and so on). Although there are many uses of the te o s ious ess i the West, phenomenal consciousness is arguably closest to its most common usage. Crucially, it is o s ious ess i the se se of phe o e al o s ious ess that poses ha d p o le s of the kind currently discussed in Weste philosoph su h as Ho ould o s ious e pe ie es affe t the a ti it of ai s? the su je t of TA I also la gel follo u e t Weste o e tio s i use of the te i d. As ith o s ious ess the te i d has a ious uses. Ho e e , in psychology it is typical to think of the human mind as that which enables us to function in certain ways (to think, to solve problems and so on). Although the details of how consciousness, mind and brain relate are i dispute, the e is o se sus that i d is i ti atel o e ted to oth ai a d consciousness. A major finding of 20th century psychology is that mental processes may or a ot e o s ious. “o e p o esses ha e asso iated phe o e al o te ts, hile others are preconscious, unconscious, or non-conscious. Consequently, in Western ps holog , i d is o o l thought of as encompassing consciousness. Easte o o usage of the te s o s ious ess a d i d is so e hat diffe e t. However it is not difficult to tease out terminological differences from genuine, theoretical ones. At first glance, the Samkhya-Yoga tradition described by Rao might look very different to Reflexive Monism. In this tradition, consciousness, with purusha20 at its center, forms the ground of one's individual being. It is the contentless container within which perspectival, phenomenal consciousness takes form. Mind, unlike consciousness, is physical in that it can be described in material forms and accounted for in physical terms. The purusha as the center of consciousness is distinct and has unique experiences through its associated mind-body complex. Such observer dependent relativity, in Yoga as well as in Vedanta, is not absolutely given but a transient condition that can be overcome by disciplined practice. The purusha finds itself reflected in the mind illuminating the material forms of the universe. Thus mind becomes as instrument through which the universe reveals itself. Subject-object distinction is not fundamental. It is a contingent manifestation of the mental process by which the u i e se is e ealed. Rao, p. 65) In my own analysis in UC I am careful to remain within the evidence base currently accepted by Western science, and I tease the modern problems of consciousness away from more t aditio al o e s ith the atu e of the soul UC, pp. 15-16). Co se ue tl , I do ot o e t o the e iste e o ope atio s of pu usha . While I have no doubt that first-person investigative attention can lead to a deeper understanding of mind (see above) I also remain neutral about whether disciplined practice can entirely e o e o e s o se e depe de t elati it , o hethe the e sui g o s ious state a be entirely contentless (UC, chapter 1, note 2).21 Nevertheless, there are broad similarities between Reflexive Monism and the Eastern view that Rao describes. Like Samkya-Yoga philosophy (and Western materialism) I accept that mind has (third-person) physical aspects that provide an instrument for the formation of phenomenal consciousness. I also accept that both phenomenal consciousness and material aspects of mind are grounded in something deeper, namely a self-revealing universe in which the subject-object distinction is not fundamental (see above). However, in my own analysis, the terms I use to refer to hat is deepe a e diffe e t. Fo e a ple, o s ious ess ith purusha at its e te , is epla ed the deepe atu e of i d o , i Ka tia fashio , i d-itself .22 18 These different uses of terms partly account for a number of confusions in Rao’s summary of my own theoretical position. Rao notes that both Indian theories and my own make a disti tio et ee o s ious ess a d i d. But he suggests that, In the Indian view; the distinction is fundamental and primary in the sense that one is not reducible to the other. I Vel a s ie , the disti tio is se o da a d holds good at the episte ologi al le el and not at the ontological level. Thus consciousness becomes a subcategory or species of the i d. In fact, however, I neve suggest that o s ious ess interpreted in the broad Eastern sense is an aspect of the material mind interpreted in the narrow Eastern sense (that would indeed be inconsistent with my view that consciousness cannot be reduced to states of the brain). What I actually suggest is that phenomenal consciousness (understood in the conventional Western sense) is an aspect of the deeper nature of mind (mind-itself). The neural correlates of consciousness and other forms of brain functioning provide the complementary, material aspect of mind-itself. Being genuine aspects, both consciousness and brain have an ontology, as well as providing first- and third-person means by which the mind can be known. Consequently Rao is wrong to suggest that the distinction between mind and consciousness in my own work is purely epistemological. And he mistakes my suggestion that mind-itself encompasses consciousness to mean that the material aspect of mind encompasses consciousness. Rather, the deeper, psychophysical nature of mind encompasses both its manifest conscious and material aspects.23 If one replaces Rao’s Easte use of the te o s ious ess ith use of the te i d-itself o o e oadl the thi g-itself o e i ediatel lea s up a u e of other confusio s. ‘ao ites fo e a ple, the disti tio et ee fi st-person consciousness and third-person consciousness adds little to the clarity of the concept of consciousness. Consciousness is consciousness whether we look at it from a first-person or the third-person perspective. It may manifest different characteristics at different levels of observation, but it underlies all awareness. Consciousness is what makes awareness possible. It is the ground condition for all forms of awareness, like matter which is the g ou d o ditio fo all the ate ial fo s e e pe ie e. p. 66) Viewed in conventional Western terms, Rao’s statement makes no sense, for the reason that phenomenal consciousness cannot be viewed from a third-person perspective (whatever the level of observation). In the West, the terms consciousness, phenomenal consciousness and conscious awareness are often used interchangeably (I do so in my own work). Consequently it makes no sense to suggest that consciousness underlies awareness (it cannot u de lie itself . The suggestio that o s ious ess is the g ou d condition for all forms of awareness, like matter which is the ground condition for all the ate ial fo s e e pe ie e is also i o siste t ith the ie that o s ious ess has ontological primacy over matter (the alternative is ontological dualism). By contrast, i d-itself can be viewed from first- and third-person perspectives, does underlie phenomenal consciousness and is the ground condition for both its conscious and material manifestations (thereby avoiding dualism). Of course, these different terms for what has ontological primacy in the East and in the West (and their corresponding descriptions) also reflect substantive theoretical differences. 19 In Samkya-Yoga philosoph consciousness with purusha at its e te is the fu da e tal reality. In Western materialism the physical world is the fundamental reality. In Rao’s opinion I have to choose between these: if I reject the reducibility of conscious experience to brain states, I must accept the primacy of consciousness. Not so. I accept that if one investigates the mind from a third-person Western perspective it will appear to be entirely physical while if one investigates it from a first-person Eastern perspective it will appear to be entirely conscious experience (see above). But, as far as I can judge, neither route to knowledge of the mind is privileged, incorrigible or complete. Rather, first- and third-person routes to knowledge of the mind are complementary and mutually irreducible. Co se ue tl , the deepe atu e of i d i d-itself) is better described as psychophysical. Rao suggests that, in my own analysis, there is an asymmetry between conscious states which do not reduce to states of the brain and nonconscious mental activities which do edu e to ai states. I his ie this leads to the eal p o le . He ites, Vel a s acknowledges that consciousness is not reducible to brain states or functions. Yet, he considers consciousness an aspect of the mind. The mind in his view is broader to include nonconscious mental activities as well. Here rests the real problem. Consciousness (subjective experience) is irreducible to neural states or brain functions, whereas the nonsubjective states of the mind are in principle reducible. In the light of such a fundamental difference between them, it is hardly plausible to argue that consciousness is a species or an aspect of the mind. The irreducibility of consciousness to physical states entails that the difference between conscious and nonconscious aspects of the mind is one of kind, primary and fundamental. Reducibility or otherwise of one category into another is a o tologi al atte a d ot si pl a episte ologi al issue. p. 66) Epistemological symmetries and asymmetries between first- and third-person perspectives are important, but I agree with Rao that reducibility is an ontological matter, not an epistemological matter. However, such an ontological asymmetry between conscious states and nonconscious ones would occur only if the nonconscious nature of mind turned out to be entirely physical (as Rao himself assumes). If so, conscious mind would have dualaspects, but nonconscious mind would only have a physical aspect. As it happens, a similar view to this is held those o edu ti e ph si alists that adopt p ope t dualis . Whethe this leads to a eal p o le depe ds o hethe su h as et ies a tuall occur in nature or not (if they do, it would be perverse to regard them as a problem). Chrisley & Sloman for example take such asymmetries for granted. As they note, There is a fundamental asymmetry between the physical and the conscious: Physical laws apply everywhere, both in situations where there is and where there is not consciousness, while the converse does not hold. So there seems to be a primacy of the physical, and one must epl to the idea that it is this ph si al, ausal ealit hi h is al a s doi g all the o k. p. 59) Rao adopts the opposite view that a pure consciousness without any material form is the basis of everything, but does not appear to recognize that this produces an inverse asymmetry (in which physical matter becomes secondary to consciousness). Whether such asymmetries actually occur in Nature is up to Nature—and whether they do or not is largely tangential to the analysis of consciousness that I have given in TA and UC. It is important to note however that, unlike both materialism and idealism, ontological asymmetries are avoidable in dual-aspect theory, which allows for the possibility that minditself has a dual-aspect, psychophysical nature irrespective of whether its operations are 20 24 unconscious, preconscious or conscious. On this interpretation, the dual-aspect nature of mind is fully manifest only in those aspe ts of i d that a e o s ious . Ho e e , ith appropriate investigative techniques, some preconscious and unconscious aspects of the mind can become conscious (in the sense that we can become aware of those aspects or to real-ize their nature).25 Unconscious and preconscious aspects of mind can also be thought of as psychophysical in the sense that they can have causal effects on both conscious experiences and physical states of the body/brain, for example in the operation of preconscious free will (see TA).26 Note that whatever view one adopts about what is primary, one is left with the problem of origins. In the West, we generally accept that the origins and existence of consciousness are somewhat mysterious (when and why did it emerge?). But we habitually ignore the fact that the origins and existence of matter are equally mysterious. Why should there be a thi g athe tha othi g? As the o igi s of a ps hoph si al i d a e also ste ious, the choice between these three positions has to be made on other grounds. Whi h ie is p efe a le? Note that the e a e ha d p o le s asso iated ith taki g eithe the material world or conscious experience to be more primary than the other. In the West it is well recognized that taking the material world to be primary leaves one with the problem of consciousness. How could something like an experience emerge from a material world that does not already have it? It is perhaps less well recognized in the East that if one takes the existence of consciousness to be primary one is left with the inverse problem. How could something like an independently existing material world emerge from something like an experience? If the thing-itself and mind-itself are fundamentally psychophysical one avoids such problems.27 And one can then make sense of mind/body interactions observed in clinical practice and everyday life. References A uth ott, K.D. , I hi ito e ha is s i Cahiers de Psychologie Cognitive, 14(1), pp. 3-45. og itio : Phe o e a a d odels , Baars, B. J., Banks, W. P. and Newman, J. B. (2002) (eds.) Essential Sources in the Scientific Study of Consciousness. Cambridge, MA: The MIT press. Chalmers, A. F. (1992), What is this Thing Called Science? Milton Keynes: Open University Press. John, E. R. 1-28. , The eu ops holog of o s ious ess , Brain Res Brain Res Rev, 39, pp. Kim, J. (1999), Mind in a Physical World, Cambridge, MA: MIT Press. Li et, B. , Ca Studies (in press). o s ious e pe ie e affe t ai a ti it ? Journal of Consciousness 21 M Fadde , J. , “ h o ous fi i g a d its i flue e o the ai s ele t o ag eti field: E ide e fo a ele t o ag eti theo of o s ious ess , Journal of Consciousness Studies, 9 (4), pp. 23-50. M Fadde , J. ha d p o le Melza k, ‘. , The o s ious electromagnetic information (Cemi) field theory: The ade eas ? , Journal of Consciousness Studies, 9 (8), pp. 45-60. , The sho t-fo M Gill Pai Questio ai e , Pain, 30, pp. 191-197. Metzinger, T. (2000) (ed.), Neural Correlates of Consciousness, Cambridge, Mass: The MIT Press. Mille , G. A. , The agi al u e se e , plus o i us t o: so e li its of ou apa it fo p o essi g i fo atio , Psych Review, 63, pp. 81 – 97. Pe u het & Vi te (in press) Po kett, “. (4), pp. 51-6. , The self-o ga izi g o s ious ess , Behavioral and Brain Sciences , Diffi ulties ith the ele t o ag eti field theo “ea le, J. , Co s ious ess, e pla ato Brain Sciences, 13(4), pp. 585-642. of o s ious ess , JCS, 9 i e sio a d og iti e s ie e , Behavioral and Thomson, E. (2001) (ed.), Between Ourselves: Second-Person Issues in the Study of Consciousness, Exeter: Imprint Academic. Varela, F. and Shear, J. (1999) (eds.), The View from Within: First person approaches to the study of consciousness, Exeter: Imprint Academic. Vel a s, M. , Is the Sciences, 13, pp. 629-630. i d o s ious, fu tio al, o Vel a s, M. a , Co s ious ess, Psychology, 3, pp. 77-99. Vel a s, M. a , Is hu a i fo Sciences, 14(4), pp. 651-701. Vel a s, M. 299-306. oth? , Behavioral and Brain ai , a d the ph si al o ld , Philosophical atio p o essi g o s ious? , Behavioral and Brain , I te su je ti e s ie e , Journal of Consciousness Studies, 6(2/3), pp. Vel a s, M. , The elatio of o s ious ess to the Consciousness Studies, 2(3), pp. 200-219. ate ial o ld , Journal of 22 Vel a s, M. , Hete ophe o e og e sus iti al phe o e olog : a dialogue ith Da De ett , http:// ogp ints.ecs.soton.ac.uk/archive/00001795/index.html 1 As Torrance points out (in his note 2), some philosophers have tried to defend identity theory by arguing that Leibniz's law does not apply to 'referentially opaque contexts'. I might have a twinge in my knee and just not know it to be identical to neural-bodily state S, so I might conclude that they are not identical even though they are. Torrance is cautious about this argument and I share his caution. In some future state of neuroscience we can envision having a given experience C, knowing all about its physical correlates B, and still not being convinced of their identity (given Leibniz's law). 2 Note that this block to establishing the ontological identity of conscious states with correlated physical states applies irrespective of the level of organisation of the physical states. That is, the block applies just as much to so- alled o edu ti e ph si alis as it does to old-style reductive physicalism. Given this, it is not obvious how Van Gulick's suggestio that highe le el egula ities ight appl i i tue of lo e le el o es ould actually resolve the problem of causal closure. 3 Whether more primitive forms of material organisation are associated with more primitive forms of conscious experience is a separate (controversial) issue that we need not address here. Panpsychists such as Penrose and Hameroff for example suggest that even microphysical events are associated with primitive experiences. 4 In Velmans (1990) for example, I defend the conventional cognitive view that many mental states are u o s ious a d take issue ith “ea le's o e tio p i iple hi h e pli itl li ks the ite io fo being mental to being potentially conscious. 5 This also addresses Chrisley & Sloman's poi t that, We d like to thi k that ou o s ious states ha e ausal power by virtue of their being the mental states that they are, not by virtue of being identical with some physical state, which itself has, i tue of falli g u de ph si al la s, the t ue ausal po e . I deed! A d that is yet another reason for rejecting any version of physicalism. In the above analysis, conscious experiences are not identical to (correlated) physical states. Nor do they supe e e o ph si al states ith the i pli atio that the latter are ontologically more basic). They are first-person manifestations of the operations of our own psychophysical minds. They have causal powers in the sense that any phenomena can have causal powers. Although they only represent the operations of mind-itself (ur mind), from a first-person perspective we can take them to be the operations of mind. 6 The need to have both first- and third-person accounts for a complete account of mind makes it clear why such accounts do not face the problem of o e dete i atio see Chrisley & Sloman). 7 Note that falsifiability is one useful criterion of a good scientific theory, but it is not an infallible criterion or the only criterion (other tests include verifiability, explanatory elegance, simplicity, sufficiency, productivity and so on). See Chalmers (1992) for a useful introduction. 8 Chrisley & Sloman suggest i thei ote that I should sa that the ph si al aspe t ust o tai at least as u h i fo atio st u tu e as the e pe ie tial aspe t athe tha lai i g the to ha e ide ti al i fo atio as the ph si al aspe t ill t pi all e ode o e i fo atio tha the e pe ie tial aspe t. I do not deny that the brain encodes far more information than that which is manifest in conscious experience, or that this information may support the formation and functioning of the correlates of experience. However, information encoded in the brain that is not encoded in experience is not, in the strict sense that I intend, a o elate of that e pe ie e. 9 As Chrisley & Sloman point out, it important to distinguish the functions that are implemented by a system from the methods it uses to implement those functions. They present this as an issue on which we disagree, suggesti g that a st o g phe o e al e pe ie e/ eu al o elate i o i g is i pli it i a al sis. But, as should have been clear from TA note 10, this is actually an issue on which we agree. 10 Standard measuring instruments include verbal rating scales, numerical rating scales, visual analogue scales and questionnaires such as the McGill Pain Questionnaire (Melzack, 1987). 23 11 Rakover also complains that phenomenal measurements cannot meet the requirements of objectivity, publicity, and repeatability. I disagree. However this is a large topic on which I have written on extensively, both in this journal (Velmans, 1999) and in UC chapter 8. Given the limitations on space in this reply I ask interested readers to refer to these prior sources. 12 If the physical differences can be consciously perceived we can say that information about physically easu a le diffe e es has ee su essfull t a s itted o t a sfo ed i to dis i i a le, phe o e al differences. Note that it is often possible for physical differences in stimuli to be detected in spite of not being consciously perceived (for example if subjects are required to guess). As this is tangential to the point at issue I will not elaborate on it here. 13 Chrisley & Sloman go o to lai , It is this eed to dista e hi self f o ph si alis hi h aises the second problem with the analogy: he admits that the videotape and the screen are ontologically distinct, yet he as supposedl defe di g a o tologi all o ist positio ! It seems Velmans ends up with the converse of the position for which he was aiming: ontological dualism, but epistemological monism (in the sense that strong assu ptio s a e ade a out i fo atio al i o i g . This o fused a al sis of the i te t of my videotape/TV screen analogy needs some unravelling. It is true that conscious experiences and their neural correlates have distinct (phenomenal and physical) characteristics and in that sense may be said to have distinct ontologies. But this does not prevent them being aspects of an underlying, unified mind, thereby making my dual-aspect theory ontologically monist (in the tradition of Spinoza). Nor does the possession of distinct phenomenal and physical characteristics prevent experiences and their correlates from encoding identical information. The videotape/TV screen analogy provides one example of how representational systems can encode identical information without having identical characteristics. It should have been obvious that I did not mean to suggest that brain states are literally a form of videotape and experiences literally a kind of TV screen or that experiences can somehow be decoupled from their physical correlates! Nor does it make sense to interpret the view that one can know (or represent) one thing in two different ways episte ologi al o is . 14 As it happe s, a ps hoph si al theo elati g i fo atio e oded i the ai s ele t o he ist to a pooled, i teg ated fo of the sa e i fo atio e oded i the ai s ele t o ag etic field has recently been proposed in this journal by McFadden (2002a,b). According to McFadden this EM field is the physical substrate of phenomenal consciousness (see also Pockett, 2002; John, 2002). While I am not committed to the details of this theo , a d do ot thi k it sol es the ha d p o le the EM field ould still ha e to ha e dual-aspects to bridge the gap from physics to phenomenal experience), it does illustrate the type of theory that I have in mind. 15 The fact that one has different (first- and third-person) forms of access to these (phenomenal and physical) aspects of mind does not alter the point that these aspects specify the mind's ontology. 16 It is hard to know what Chrisley & Sloman ea a magnetic way of looking at the situatio . Unlike them, I do not confound the dual-aspect ontology of mind, or the way information is formatted within its phenomenal and physical aspects, with first- versus third person ways of examining the mind's phenomenal and physical aspects. Likewise, I do not confound the electrical and magnetic manifestations of electromagnetism, or the possibility of encoding information in either electrical or magnetic formats, with the different ways in which we can investigate electricity and magnetism. 17 As I point out in TA note 14, I am only concerned here with the broader implications of dual-aspect monism. Consequently, it seems to me useful to suggest that there might be a psychophysical unity underlying the phenomenal and physical aspects of mind that is broadly analogous to the electromagnetic unity underlying electricity and magnetism. It goes without saying that I am not suggesting that conscious phenomenology is magnetism, or that its physical correlates are electricity. The precise way that given conscious experiences map onto their physical correlates can only be discovered by neuropsychological research and, in this sense, e ui es fu the o k. 18 The appearance of the 3D phenomenal physical world is not of course identical to the more abstract world described by physics (quantum mechanics, relativity, string theory and so on). The relation of the phenomenal physical world to the world described by physics is central to a proper understanding of consciousness/material world relationship and I discuss this in depth in UC chapters 6 and 7. As this relationship is somewhat tangential to the issues raised in TA and the commentaries I will not elaborate on it here. 24 19 Rao also aises a u e of uestio s i passi g, fo e a ple, hat is ea t i fo atio st u tu e , hat e odes that i fo atio , ho does pe spe ti al s it hi g o k, a d i hat se se is i fo atio viewed from a first- and a third-person perspective complementary. As I have dealt with these issues earlier in this epl I o t etu to them here. 20 In the Samkhya-Yoga tradition, Purusha refers to one's true, individual, immaterial essence (also referred to as Atman or soul). 21 Rao ites that Vel a s speaks of di e t a d i di e t k o ledge, as the I dia theo ies do. … I Yoga theory, even the so-called first-person experience is indirect, because what the mind presents to consciousness are representations mediated by the perceptual and cognitive systems. Consequently, awareness arising from such mediation is also indirect. In other words, in Velmans, the direct acquaintance is with the representations, whereas in Yoga it is with the things themselves. Such direct knowledge results when the mind detaches itself from the sensory inputs and makes contact directly with the objects, events and processes in the universe. This is what may be labelled as paranormal process distinguished from the normal process in which there is the involvement of the sensory processes. pp. -8 Ho e e , this does t quite capture the similarities and differences between Reflexive Monism and the Yoga theory that Rao describes. In UC chapter 7 I develop the view that, under normal conditions, we have direct acquaintance with our own experiences but only indirect acquaintance with the things-themselves that such experiences represent. Given that normal experiences are representations, I agree with the Yoga view that they only provide indirect knowledge of things themselves, even when the things themselves that we experience are the operations of our own minds. Nevertheless, contra Kant, I argue that the thing-itself (including minditself) is knowable through the representations that we have of it, and the aim of both first- and third-person science is to achieve deeper, more complete knowledge. Knowledge can be gained through direct acquaintance, by experiencing that which one seeks to know, or indirectly, through the use of symbols (description, theory and so on). But it is only through direct experience that things become subjectively real for us (we real-ize what they are like). One can only really know love for example by real-izing what it is like to be in love. This, I think, gets quite close to the Yoga view, with the caution that I remain non committal about the possibility (often suggested in Yoga philosophy) that it is possible for embodied human beings to fully know (real-ize) the thing-itself as it is i itself, that is to ha e di e t k o ledge i the se se of k o ledge that is pe fe t a d o plete . I also do ot o e t i UC o the atu e and existence of paranormal phenomena. 22 In this usage, mind-itself is that aspect of the thing-itself (the ground of being) that forms the basis of the a ifest aspe ts of o e s o i d i.e. its thi d-person, material and first-person, phenomenal consciousness aspects). 23 Other confusions in Rao’s commentary can be traced to differences in use of terms combined with differences that arise from taking a first-person route to the nature of mind to be more primary than a thirdperson route. Rao for example claims that equating consciousness with phenomenal consciousness entails o fusio et ee the o te ts a d the o tai e , et ee su sta e a d fo . I a ept that, ie ed from an Eastern first-person perspective, a form of pure contentless consciousness might appear to underlie everyday phenomenal consciousness, and the former therefore is viewed as the container of the latter. However, my own, somewhat different dual-aspect analysis does not confuse contents and container, or substance and form. Rather, the container is mind-itself and the suggested nature of this container is a little different. While I remain open to the view that with appropriate first-person training, the nature of mind itself appears as a form of pure, contentless consciousness, dual-aspect monism would suggest that even a conscious state as basic as this would have correspondingly basic, physical aspects that could, in principle, be discovered by empirical research. As the nature of mind-itself encompasses all its aspects it seems more accurate to describe it as psychophysical. 24 My analysis of consciousness (in TA and in UC chapters 1-11) deals largely with phenomenal consciousness in humans and is consequently neutral about whether there is a first-person aspect (latent or manifest) in states other than those that actually have manifestations in (recognisable) conscious experience. UC chapter 12, however, is more speculative and considers the evolution and distribution of consciousness. It compares dis o ti uit theo that o s ious ess appea ed sudde l at a gi e poi t i e olutio ith o ti uit theory (that the potential for recognisable consciousness was there from the beginning and evolved in form as matter evolved in form). Although little of my detailed analysis of consciousness depends on it, I argue that the latter is more intellectually elegant, and it fits more naturally into Reflexive Monism. The view that 25 consciousness is a natural accompaniment of material forms also has implications for how one might think about the necessary and sufficient conditions for consciousness in the human brain. Rather than thinking of consciousness as something that is mysteriously added to representations at the focus of attention, it can be thought of a natural aspect of neural information processing as such. Why is it apparently absent in unconscious and preconscious processing? One possibility is that, in the evolution of complex brains with multiple sources of information, massive inhibition of information became a biological necessity to enable focus on information of greatest importance, and with it, inhibition of consciousness. On this view, unconscious and preconscious mental processes have inhibited consciousness. Conversely, information at the focus of attention is subject to release from inhibition (see Arbuthnott, 1995, for a review of the evidence, and the discussion of this and alternative theories in Velmans, 1995). Another possibility is that representations at the focus of attention are activated to a degree that masks any consciousness associated with other representations, rather like an orchestra on stage masks whispers in the audience. 25 Many methods have been developed in both the West and the East for gaining conscious access to otherwise nonconscious aspects of mind, ranging from methods to aid recall of unconscious material in cognitive psychology and psychotherapeutic practice, close attention to the phenomenology of otherwise preconscious mental operations (Varela & Shear, 1999), meditative practices in Yoga and so on. 26 Due to la k of a aila le spa e I dis uss the otio of p e o s ious f ee ill , i t odu ed i TA, i a late issue of JCS along with commentaries by Libet, Mangan, and Claxton. It is interesting to note, however, that Gray, and Chrisley & Sloman wholeheartedly agree that free will is preconscious as well as conscious, in spite of there being other aspects of my analysis with which they disagree. 27 Although, following Rao, I have presented the Eastern view as idealist, it is important to note that there are as many differences in Eastern philosophy about these basic issues as there are in Western thought. The combined material and conscious nature of the thing-itself is well recognised, for example, in major, modern interpretations of Vedanta such as that of Aurobindo. 26