You are currently browsing the category archive for the ‘Type Identity Theory’ category.
|Philosophical Thesis||Type Identity
|Realism – Pain is real.||Yes||No|
|Materialism – Pain is neurophysiological.||Yes||Yes|
|Minimal Reductionism – Pain is nothing more than neurophysiological mechanism.||Yes||Yes|
|Identity – Pain is identical to a
|Naturalistic – Philosophies of pain are both metaphysical and scientific theories.||Yes||Yes|
|Theoretical – Metaphysical theories of pain can
be assessed according to their theoretical virtues (e.g., simplicity), and competing empirical predictions.
Polger, T. W. (2011). Are sensations still brain processes? Philosophical Psychology, 24(1), 1-21.
The personal experience of pain produces a reliable effect on facial behavior in humans and in nonhuman mammals. Why should pain have a face? What is it for? I will attempt to head towards answering this question by invoking a theoretical framework: polyvagal theory (Porges, 2001, 2006).
1 Polyvagal Theory
According to polyvagal theory (Porges, 2001, 2006), evolution of neural control within the autonomic nervous system (ANS) has tracked three stages, each revealing a specific behavior, and a specific function:
In the first stage, the ancient unmyelinated visceral vagus nerve that enables digestion could respond to danger and pain only by reducing metabolic output and producing immobilization behaviors.
In the second stage, the sympathetic nervous system (SNS) made it possible to increase metabolic activity and inhibit the visceral vagus nerve, thus allowing fight/flight behaviors following perceived threat or pain.
The third stage, which is uniquely mammalian, involves a myelinated vagus that can rapidly control cardiac and bronchi output to enable spontaneous interaction (i.e., engagement or disengagement) with the environment. The interaction of the autonomic nervous system (ANS) with the hypothalamo-pituitary-adrenal (HPA) axis, nervous and immune systems change to maximize response to stressors such as nociception. During nociception, the ANS operates together with nervous, endocrine and immune systems to produce stress (Chapman et al. 2008; Porges, 2001, 2006). In terms of polyvagal theory, pain facial expression is a dynamic autonomic response caused by noxious signaling. In terms of polyvagal-type identity mechanistic theory pain facial expression is a type of behavior that is identical to a type of neurophysiological mechanism; namely, the phylogenetically recent brain-heart-face mechanism.
The expansion of cortex in the third stage increased innervation and neural control of the mammalian face: upper face innervation is bilateral and arises from the supplementary motor area (M2) and the rostral cingulate motor area (M3). Lower face innervation is contralateral and arises from primary motor cortex (M1), ventral lateral premotor cortex, and the caudal cingulate motor cortex (M4) (Morecraft et al. 2004). Human pain facial movements of the eyebrows and upper lip are type identical with negative emotional aspects of pain and activation of M1, M2, M3, whereas facial movements around the eyes are type identical with somatosensory aspects of pain, and activation of M2 and M3 (Kunz et al. 2011). Thus, evolution of cranial anatomy enabled a highly integrated facial representation of the multidimensional experience of pain.
2 Why Pain Should Have a Face
In clinical and experimental settings, the pain face is observed to rapidly appear following noxious stimulation, and diminish concurrent with cessation of the noxious stimulus, or when analgesics are administered (e.g., Craig & Patrick, 1985). The brain-heart-face mechanism is an integrated system with both a somatomotor part controlling the striated facial muscles and a visceromotor part controlling the heart through a myelinated vagus nerve (Porges, 2001, 2006). When the vagal tone to the cardiac pacemaker is high, the myelinated vagus acts as a brake or restraint limiting heart rate. Rapid inhibition and disinhibition of vagal tone to the heart supports the rapid mobilization of facial muscles and formation of the pain face concurrent with pain onset. In humans and nonhuman mammals, the main vagal inhibitory pathways in the myelinated vagus originate in the nucleus ambiguus.
The vagal brake supports the low-metabolic requirements involved in the rapidly appearing and disappearing pain face. Withdrawal of the vagal brake is strongly correlated with the rapid appearance of the pain face; reinstatement of the vagal brake is strongly correlated with the rapid diminishing of the pain face. These correlations are not unique to pain facial expression; similar relationships hold with regard to the vagal brake and the timing and duration of aversive, but non-noxious emotional facial expressions (e.g., Pu et al. 2010), and positive emotional facial expressions (e.g., Kok & Fredrickson, 2010).
In terms of the function of rapid pain face onset and offset, the vagal brake makes it possible for the individual in pain to quickly disengage from source of wounding and pain, concurrent with the rapid appearance or diminishing of pain facial expression, which may offer temporary access to additional metabolic resources to aid healing, recovery and self-soothing behaviors, with likely involvement from care givers.
Concerning aid from others, the vagal brake reliably maps onto specific interaction types observed in mammalian pain events. In pain events comprising the individual in pain and care givers, mammalian behavior is typed according to interpersonal communication through facial expressions, vocalizations, head and hand gestures (Hadjistavropoulos et al. 2011; Porges, 2001, 2006; Williams, 2002). A relevant feature is the rapid ‘switching’ of temporary engagement to temporary disengagement behaviors between the individual in pain and care givers. This interaction type may involve care givers speaking to the one in pain, and then quickly switching to listening; for the one in pain, looking into the face of the care giver, and then quickly switching to vocalizing (Craig et al. 2011; Hadjistavropoulos et al. 2011; Porges, 2001, 2006; Williams, 2002). The brain-heart-face mechanism thus allows the one in pain and the care giver to get the timing right. Some philosophers and neuroscientists claim that evolutionary neurobehavioral solutions to timing problems such as these are implicated in the origin of empathy and ultimately consciousness itself (Churchland, 2002; Cole, 1998; Engen & Singer, 2012; van Rysewyk, 2011).
However, if pain is severe or chronic and the vagal brake is withdrawn (or dysfunctional), the concurrency of increased pain facial expression, cardiac output, and other mobilization behaviors (i.e., increased SNS and HPA output), means that, if care giving is to succeed in promoting healing and recovery, the care giver’s vagal brake must be dynamically reinstated. By applying their own vagal brake, care givers may regulate their own visceral distress and thereby succeed in allocating valuable metabolic resources to communicate safety to the one in pain (and themselves) through calming facial and head behaviors, eye gaze, and prosodic vocalizations (i.e., increasing the vagal brake decreases SNS and HPA output). Since the vagal brake of the person in pain has been provisionally withdrawn, the care giver is effectively an integrated external brain-heart-face mechanism (cf. Tantam, 2009, the ‘interbrain’).
Thus, the pain facial muscles function as neural timekeepers detecting and expressing features of safety and danger that cue the one in pain to quickly disengage from the source of wounding and pain, simultaneous with the rapid appearance or attenuation of pain facial activity, and also cue others who can help.
Chapman, C. R., Tuckett, R. P., & Song, C. W. (2008). Pain and stress in a systems perspective: reciprocal neural, endocrine, and immune interactions. Journal of Pain, 9(2), 122-145.
Churchland, P. S. (1989). Neurophilosophy: Toward a Unified Science of the Mind-Brain. Cambridge, Mass.: MIT Press.
Cole, J. (1998) About face. Cambridge, Mass.: The MIT Press.
Craig, K. D., & Patrick, C. J. (1985). Facial expression during induced pain. Journal of Personality and Social Psychology, 48(4), 1080-1091.
Craig, K. D., Prkachin, K. M., & Grunau, R. E. (2011). .The facial expression of pain. In D. C. Turk, & R. Melzack, Handbook of Pain Assessment, 2nd Edition (pp. 117-133). New York: The Guilford Press.
Engen, H. G., & Singer, T. (2012). Empathy circuits. Current Opinion in Neurobiology, 23, 1-8.
Hadjistavropoulos, T., Craig, K. D., Duck, S., Cano, A., Goubert, L., Jackson, P. L., Mogil, J. S., Rainville, P., Sullivan, M. J. L., de C. Williams, Amanda C., Vervoort, T., & Fitzgerald, T. D. (2011). A biopsychosocial formulation of pain communication. Psychological Bulletin, 137(6), 910-939.
Kok, B. E., & Fredrickson, B. L. (2010). Upward spirals of the heart: Autonomic flexibility, as indexed by vagal tone, reciprocally and prospectively predicts positive emotions and social connectedness. Biological Psychology, 85(3), 432-436.
Kunz, M., Lautenbacher, S., LeBlanc, N., & Rainville, P. (2011). Are both the sensory and the affective dimensions of pain encoded in the face? Pain, 153(2), 350-358.
Morecraft, R. J., Stilwell-Morecraft, K. S., & Rossing, W. R. (2004). The Motor Cortex and Facial Expression: New Insights From Neuroscience. The Neurologist, 10(5), 235-249.
Porges, S. W. (2001). The polyvagal theory: phylogenetic substrates of a social nervous system. International Journal of Psychophysiology, 42(2), 123-146.
Porges, S. W. (2006). Emotion: An Evolutionary By‐Product of the Neural Regulation of the Autonomic Nervous System. Annals of the New York Academy of Sciences, 807(1), 62-77.
Pu, J., Schmeichel, B. J., & Demaree, H. A. (2010). Cardiac vagal control predicts spontaneous regulation of negative emotional expression and subsequent cognitive performance. Biological Psychology, 84(3), 531-540.
van Rysewyk, S. (2011). Beyond faces: The relevance of Moebius Syndrome to emotion recognition and empathy. In: A. Freitas-Magalhães (Ed.), ‘Emotional Expression: The Brain and the Face’ (V. III, Second Series), University of Fernando Pessoa Press, Oporto: pp. 75-97.
Williams, A. C. D. C. (2002). Facial expression of pain: an evolutionary account. Behavioral and Brain Sciences, 25(4), 439-455.
I invite you to complete a 5 minute survey to assess the status of the mind-brain identity theory in current professional philosophy. It is open to philosophy faculty members and philosophy graduate and undergraduate students.
In the survey, the mind-brain identity theory is represented as a list of 9 philosophical claims adapted with permission from Thomas W Polger’s paper ‘Are Sensations Still Brain Processes?’ (2011), and which correspond to claims philosopher Jack Smart defended over fifty years ago in his paper ‘Sensations are Brain Processes’ (1959).
In the survey, each claim in the list is a binary ‘yes/no’ question. There are 9 questions. I will publish the results on my webblog and in an article.
Simon van Rysewyk
Abstract. Functionalism of robot pain claims that what is definitive of robot pain is functional role, defined as the causal relations pain has to noxious stimuli, behavior and other subjective states. Here, I propose that the only way to theorize role-functionalism of robot pain is in terms of type-identity theory. I argue that what makes a state pain for a neuro-robot at a time is the functional role it has in the robot at the time, and this state is type identical to a specific circuit state. Support from an experimental study shows that if the neural network that controls a robot includes a specific ’emotion circuit’, physical damage to the robot will cause the disposition to avoid movement, thereby enhancing fitness, compared to robots without the circuit. Thus, pain for a robot at a time is type identical to a specific circuit state.
UC Berkeley psychologist Tania Lombrozo has responded to the Annual Edge Question for 2014, ‘What scientific idea is ready for retirement?’, with a piece entitled ‘The Mind is Just the Brain’, in which she argues for the rejection (‘retirement’) of mind-brain identity theory.
Using a baking analogy to illustrate her case against reductionism, she writes:
But a theory of baking wouldn’t be very useful if it were formulated in terms of molecules and atoms. As bakers, we want to understand the relationship between—for example—mixing and texture, not between kinetic energy and protein hydration. The relationships between the variables we can tweak and the outcomes that we care about happen to be mediated by chemistry and physics, but it would be a mistake to adopt “cake reductionism” and replace the study of baking with the study of physical and chemical interactions among cake components.
But if you are interested in the project of explaining, predicting, and controlling the quality of your baked goods, then you’ll need something like a baking theory to work with.
Rejecting the mind in an effort to achieve scientific legitimacy—a trend we’ve seen with both behaviorism and some popular manifestations of neuroscience—is unnecessary and unresponsive to the aims of scientific psychology.
In these passages, Lombrozo makes a common anti-reductionistic mistake of thinking that mind-brain identity makes mental experiences somehow unreal or even disappear. Her reasoning implies that a correct explanation of mental phenomena cannot involve scientific reduction of mental phenomenon to neurobiological mechanism. This misunderstanding trades on a peculiar view of reduction, where it is expected that in neuroscience, mind-brain identities eliminate mental experiences. I think this expectation is incorrect.
Temperature was ontologically reduced to mean molecular kinetic energy, but no person expects that temperature therefore ceased to be real or became scientifically disrespectable or redundant. Visible light was ontologically reduced to electromagnetic radiation, but light did not disappear. Instead, scientists understand more about the real nature of light than they did before 1873. Light is real, no doubt; and so is temperature. Some expectations about the nature of temperature and light did change, and scientific progress does occasionally require rethinking what was believed about phenomenon. In certain instances, previously respectable states and substances sometimes did prove to be unreal. The caloric theory of heat did not survive rigorous experimental testing; caloric fluid thus proved to be unreal. A successful mind-brain identity of mental phenomenon such as pain means only that there is an explanation of pain. It is a reduction. Scientific explanations of phenomenon do not typically make them disappear [1,2,3].
It is critical to clear-up a further common misconception about mind-brain identity theory. This is the misconception that mind-brain identity theory is equivalent to reductionism. The truth is that whereas identity theory is compatible with a wide range of reductionistic philosophies, it is not equivalent to all of them. Here are some illustrative examples :
1) Identity theory is reductionistic in the sense that it denies minds are ontologically independent of brains and uniquely self-guaranteeing, in line with functionalist and realization (physicalist) philosophies of mind. But functionalism and realization physicalism are not equivalent to the identity theory, so identity theory is not uniquely reductionist in the sense of (1).
2) Identity theory is reductionistic in the minimal sense that it claims, in line with functionalist and realization (physicalist) philosophies, that mind is ‘nothing over and above’ the brain, but since identity theory and functionalist and realization philosophies are not equivalent, identity theory is not equivalent to reductionism. A philosopher could be a reductionist without being an identity theorist.
3) Identity theory is not reductionistic in the sense that it asserts ‘micro-reductionism’. Mental phenomena might be identified with innate genetic or molecular mechanisms (John Bickle), but this is optional, not required. The core metaphysical commitment of identity theory is that mental states are numerically identical to brain states. Nothing is expected in this core claim about the precise mechanistic nature of brain states, which is a scientific question, anyway.
4) Identity theory is not reductionistic in the sense that it asserts that (e.g.) psychology reduces to neuroscience, cognitive neuroscience reduces to molecular neuroscience, or philosophy of mind reduces to quantum mechanics. One can assert identity theory without asserting epistemic reductionism.
Positively, I entirely agree with Lombrozo when she says:
But if we want to know—for instance—how to influence minds to achieve particular behaviors, it would be a mistake to look for explanations solely at the level of the brain.
Understanding the mind isn’t the same as understanding the brain.
Understanding the mind requires first-person descriptions of mental states and experiences, and third-person scientific descriptions of associated brain states, and a method to integrate them, such as the experiential-phenomenological method . So, Lombrozo is right: ‘Understanding the mind isn’t the same as understanding the brain.’ More precisely, I argue that her correct thesis implies that the subject matter of psychology is brain mechanism as related to mental phenomena. For example, the subject of pain science is brain mechanism as related to pain phenomena (e.g., acute pain, chronic pain, fetal pain, empathy for pain, dreamed pain, near-death pain, and so on). Pain research aims to discover the brain mechanisms subserving conscious pain experiences accessible only through introspection, which means that pain research is entirely reliant on the first-person point of view and on using first-person investigative methods. This necessarily includes introspection together with third-person methods (e.g., neuroimaging). Since pain research aims to know which experience types are generated by which brain mechanism, researchers must naturally know when specific pain experiences occur and what their personal qualities are.
The history of scientific pain research shows that introspection has been extensively used. For example, pain psychophysics typically uses subject pain verbal-report or non-verbal behavior (e.g., facial expressions) to infer the presence of pain. That is, pain psychophysics is committed to subject introspection. It is also important to remember that the validity of pain-related neuroimaging was established by the correlation of brain images with self-report of pain . Pain psychophysics, like psychology, preserves an epistemological dualism in its subject matter while rejecting metaphysical dualism.
How then is mind-brain identity theory positioned relative to the indispensability of introspection in mind science? Personal introspection is a direct way of coming to know about personal experiences and their qualities. It is epistemological. Still, despite appearances to the contrary, what introspection reveals to us may be utterly mechanistic. It may be that what scientists study through third-person methods is numerically identical with what is personally experienced through introspection, that is, brain mechanisms of the appropriate type. There is only one type of activity in question: the brain mechanism with all and only physical properties. Thus, mind-brain identity theory is preserved in the study of the mind.
 Churchland PM (2007). Neurophilosophy at work. Cambridge, UK: Cambridge University Press.
 Churchland PS (1989). Neurophilosophy: Toward a unified science of the mind-brain. Cambridge, Mass.: The MIT Press.
 van Rysewyk S (2013). Pain is Mechanism. PhD Dissertation, University of Tasmania.
 Polger TW (2009). Identity Theories. Philosophy Compass, 4(5), 822-834.
 Price DD, Aydede M (2006). The Experimental Use of Introspection in the Scientific Study of Pain and its Integration with Third-Person Methodologies: The Experiential-Phenomenological Approach. In M Aydede (ed.), Pain: New Essays on Its Nature and the Methodology of Its Study, pp. 243-275. Cambridge, Mass.: MIT Press.
 Coghill RC, McHaffie JG, Yen YF (2003). Neural correlates of interindividual differences in the subjective experience of pain. Proceedings of the National Academy of Science USA, 100, 8538-8542.
In this first post of a series, I describe and challenge several criticisms of reductive materialism, or mind-brain identity theory [5,6,7,8,9,10], made by psychologist Max Velmans. My focus in this post concerns Velmans’s arguments against mind-brain identity theory as presented in ‘What non-eliminative materialism needs to show’ in Appendix I of . Future posts will address his other arguments against mind-brain identity theory as presented in the same work. My intention here is not simply negative, but also positive: using the first-person third-person distinction Velmans appeals to, I propose that the first-person point of view (introspection) and first-person methods are necessary to consciousness science. In developing this view, I focus mostly on pain.
Velmans is a long-time critic of materialist theories of phenomenal consciousness [1,2,3,4]. Following philosopher CD Broad, Velmans distinguishes three versions of materialism: radical, reductive and emergent. He writes :
Radical materialism claims that the term “consciousness” does not refer to anything real (in contemporary philosophy this position is usually called “eliminativism”). Reductive materialism accepts that consciousness does refer to something real, but science will discover that real thing to be nothing more than a state (or function) of the brain. Emergentism also accepts the reality of consciousness but claims it to be a higher-order property of brains; it supervenes on neural activity, but cannot be reduced to it. [4,20]
Velmans begins his argument against mind-body identity theory:
Let us assume that, in some sense, our conscious experiences are real. To each and every one of us, our conscious experiences are observable phenomena (psychological data) which we can describe with varying degrees of accuracy in ordinary language. Other people’s experiences might be hypothetical constructs, as we cannot observe their experiences in the direct way that we can observe our own, but that does not make our own experiences similarly hypothetical. Nor are our own conscious experiences “theories” or “folk psychologies.” We may have everyday theories about what we experience, and with deeper insight, we might be able to improve them, but this would not replace, or necessarily improve the experiences themselves. [4,20-21]
In this passage, Velmans denies that our conscious experiences are ‘theories’ or ‘folk psychologies.’ However, since that is a central claim made by radical materialism (‘eliminativism’) [5,6], not reductive materialism (mind-brain identity theory), Velmans is in error to attribute it to the latter. Like mind-brain identity theory, eliminativism accepts the claim that conscious states are ‘nothing over and above’ brain states (minimal reductionism), but it rejects type identity. This is because eliminativism denies that conscious states are real, and do not exist . By contrast, mind-brain identity theory is realist about mental states and experiences . Mind-brain identity theory is not equivalent to eliminativism  (1).
The final sentence in the quote above reads: ‘We may have everyday theories about what we experience, and with deeper insight, we might be able to improve them, but this would not replace, or necessarily improve the experiences themselves.'[my italics] Critics of mind-brain identity theory, like Velmans, believe that a successful scientific reduction of consciousness would make all conscious experiences somehow unreal or even disappear [e.g., 17,18]. Using this conception of reduction, it is then reasoned that because it is observably obvious that a conscious experience like pain is real, it cannot be reduced by science to neurobiological mechanism. This misunderstanding trades on a peculiar view of reduction, where it is expected that in science, type identity claims make conscious experiences disappear. I think this expectation is incorrect.
Temperature was ontologically reduced to mean molecular kinetic energy, but no person expects that temperature therefore ceased to be real or became scientifically disrespectable or redundant. Visible light was ontologically reduced to electromagnetic radiation, but light did not disappear. Instead, scientists understand more about the real nature of light than they did before 1873. Light is real, no doubt; and so is temperature. Some expectations about the nature of temperature and light did change, and scientific progress does occasionally require rethinking what was believed about phenomenon. In certain instances, previously respectable states and substances sometimes did prove to be unreal. The caloric theory of heat did not survive rigorous experimental testing; caloric fluid thus proved to be unreal. Thus, a successful type identity of pain with mechanism means only that there is an explanation of pain. It is a reduction. But, scientific explanations of phenomenon do not typically make them disappear [5,6,10].
Velmans continues his argument:
In essence then, the claim that conscious experiences are nothing more than brain states is a claim about one set of phenomena (first-person experiences of love, hate, the smell of mown grass, the colour of a sunset, etc.) being nothing more than another set of phenomena (brain states, viewed from the perspective of an external observer). Given the extensive, apparent differences between conscious experiences and brain states this is a tall order. [4,21]
By characterizing mind-brain identity theory as a ‘tall order’, Velmans is in danger of begging the question. It is possible that science will never understand how brain structures such as neurons and protein channels produce pains, emotions and thoughts. The reality of the brain may be forever closed to us. Still, that the problem of consciousness is scientifically tractable or intractable, solvable or insolvable, is impossible to tell simply by noting appearances, since problems do not rank level of difficulty on their sleeves. Why should the problem of consciousness be any different?
Besides, things change. Over time, the nature of a problem may alter shape as new knowledge and understanding arrive. A problem may come to be viewed in novel ways as a result of reciprocal developments in technology, scientific methods and theory. For example, the composition of stars was regarded by scientists as an intractable problem. The problem was that it was impossible to get close enough to collect a star sample without burning up. However, with the unexpected discovery of spectral analysis, this problem proved tractable. The elements of stars were found to produce a type of fingerprint when heated to incandescence, easily observed when light produced from a source is passed through a prism.
In the early twentieth century, the copying problem in molecular genetics was thought to be intractable. This problem, however, was solved in the decades following Watson and Crick’s 1953 publication that DNA is a double helix. By contrast, the problem of how protein molecules fold into their 3D shape once made, believed by many scientists to be solvable in the mid-twentieth century, remains entirely unsolved today despite many decades of effort. Moreover, contributing solutions to twenty-first century problems can come from surprising and novel sources that may challenge conventional thinking. What seems apparently true or observably obvious during immediate experience or armchair reflection is sometimes a poor guide to reality.
Instances where phenomena viewed from one perspective turned out to be one and the same as seemingly different phenomena viewed from another perspective do occur in the history of science. A classical example is the way the “morning star” and the “evening star” turned out to be identical (they were both found to be the planet Venus). But viewing consciousness from a first- versus a third-person perspective is very different to seeing the same planet in the morning or the evening. From a third-person (external observer’s) perspective one has no direct access to a subject’s conscious experience. Consequently, one has no third-person data (about the experience itself) which can be compared to or contrasted with the subject’s first-person data. [4,21]
It is unclear what Velmans means by ‘From a third-person (external observer’s) perspective one has no direct access to a subject’s conscious experience.’ I presume he intends that what I experience during a conscious episode cannot be available to you or indeed any one else in the way it is directly available to me. I occupy a uniquely privileged position concerning my experience that no one else can occupy. But if so, then he is intuitively characterizing the problem of consciousness in terms of method of access, and in terms of a privileged mode of access at that, namely, ‘direct’ personal introspection, which is question-begging.
This intuitive take on the problem of consciousness also results in a misrepresentation of what science is really up to, since the scientific enterprise relies on the intersubjective availability of its subject matter, in that no one is privileged with regard to collecting evidence about the object of the study. This means that no one has any special epistemic authority over evidence that others cannot in principle understand. In principle, must a successful reduction of pain produce a scientific explanation and pain? Obviously, no – scientific pain research aims to explain pain; it is not in the business of spontaneously concocting the phenomenon in question. To think otherwise is to misrepresent the limits and possibilities of science [5,6,10].
Now, there is a positive characterization of Velmans’s appeal to the first-person and third-person distinction I wish to show. Velmans’s description of the consciousness landscape should be taken to imply that the subject matter of consciousness research is brain mechanism as related to conscious phenomena. For example, the subject of pain science is brain mechanism as related to pain phenomena (e.g., acute pain, chronic pain, fetal pain, empathy for pain, dreamed pain, near-death pain, and so on). Consciousness research aims to discover the brain mechanisms subserving conscious experiences accessible only through introspection, which means that consciousness research is entirely reliant on the first-person point of view and on using first-person investigative methods. Contrary to Velmans’s view, this necessarily includes introspection together with third-person methods (e.g., neuroimaging). Since consciousness research aims to know which experience types are generated by which brain mechanism, researchers must naturally know when specific conscious experiences occur and what their personal qualities are. Which means that introspection is indispensable to consciousness research.
The history of scientific pain research clearly shows that introspection has been extensively used. For example, pain psychophysics typically uses subject pain verbal-report or non-verbal behavior (e.g., facial expressions) to infer the presence of pain. That is, pain psychophysics is committed to subject introspection. It is also important to remember that the validity of pain-related neuroimaging was established by the correlation of brain images with self-report of pain .
Neurophysiological investigations are limited, in principle, to isolating the neural correlates or antecedent causes of given experiences. This would be a major scientific advance. But what would it tell us about the nature of consciousness itself? [4,21]
I will respond to Velmans’s question with my own: how is mind-brain identity theory positioned relative to the indispensability of introspection to consciousness research? As Velmans notes, introspection is a direct way of coming to know about personal experiences and their qualities. It is an epistemological activity. Still, despite appearances to the contrary or personal conviction, what introspection reveals to us may be utterly mechanistic. It may be that what neuroscientists study through third-person methods is type identical with what is personally experienced through introspection, that is, brain mechanisms of the appropriate type. There is only one type of activity in question: the brain mechanism with all and only physical properties.
Mind-brain identity theory follows a long line of identifications that have marked progress in knowledge: water is H2O, light is electromagnetic energy, lightning is electrical discharge, influenza is a viral infection, and so on. Each of these identities is part of a larger theory that was accepted because it provided a better explanation of the evidence than rival theories. To illustrate this claim, take the conventional example of the type identity of fire and rapid oxidation. Why is this type identification descriptive (i.e., informative)? The first step is to conduct a qualitative investigation of fire. The flame is the visible part of fire, it releases heat and light, is normally sustained by a continuous supply of fuel, and so on. Some qualitative facts about fire are easily observed and others take further investigation, for instance, facts about the reactions that make fire explode. This provides a provisional description of fire. These qualitative descriptions (facts) about fire are then matched with qualitative descriptions (facts) about the operation of rapid oxidation, which is the sequence of chemical reactions between a fuel and an oxidant, such as oxygen or fluorine gas. These facts are harder to describe but essential. When sufficient information is at hand concerning the parts and operations of fire and the parts and operations of specific chemical reactions (rapid oxidation), we can describe how the structure of fire delineates its qualitative chemical properties. The multilevel mechanistic description of fire type identifies it with a specific mechanism type, rapid oxidation, and describes its behavior in terms of the behavior and composition of this mechanical operation. Fire is rapid oxidation.
The type identification of fire and rapid oxidation is only enabled if other substances are also type identified with other molecules, and if elements are type identified with chemical types, and so on. That is, the type identity of fire and rapid oxidation works because it is framed in the broader descriptive context of chemistry and physics. Those general framework theories imply the type identifications. Of course, the type identification of fire and rapid oxidation might be faulted as an incorrect description, perhaps because the physical operations involve activity in a broader range of physical processes. But that criticism merely asserts a different type identity description, and does not challenge type identity claims per se. It is conceivable to ponder whether fire is correctly type identified with rapid oxidation rather than with some other operation; but within the framework of chemistry and physics as they are understood, it is not reasonable to ponder whether fire might fail to be any type of mechanical operation at all.
In the same way, mind-brain identity theory is part of a rich theory that aims to explain conscious and unconscious mental phenomena such as perception, memory, reasoning, addiction, and disease. The personal experience of pain is multidimensional and involves specific sensory, emotional and cognitive features. I think there is a well established multilevel view of the physiological mechanisms that best describes pain qualities. This mechanistic description is framed within the context of advancing theories of the nervous, endocrine and immune systems and their complex functional interdependencies. There are also complex adaptive system-based descriptions of pain experience. Taken together, these descriptions reveal how pain is type identified with mechanism .
Although empirical progress in the understanding of pain is typically gradual and piecemeal, the type identification of pain with brain mechanism does not proceed in an additive manner. Pain scientists do not discover one pain type identity at a time and then add them together. Rather, what justifies claims to have type identified the mechanisms of pain is the way the entire multilevel mechanistic package coheres .
1. Briefly, the central argument for eliminativism is the idea that we use a theoretical framework to explain and predict human behavior , usually called the theory-theory (TT). TT views folk psychology (FP) as comprising specific theoretical claims and generalizations (and laws), described by our everyday common-sense psychological (i.e., mental) words such as ‘belief’, ‘desire’, ‘recognition’, ‘fear’, ‘anticipate’, ‘memory’ or ‘pain’. FP generalizations are thought to describe the diverse causal regularities and relations of FP claims.
TT claims that FP generalizations and claims operate in FP much like the generalizations and laws of scientific theories. However, the laws of FP are acquired more informally than scientific theories, as part of normal human development [e.g., 12,13,14,15]. For example, children who observe their parents showing fear and behavioral avoidance to back-stressing tasks, such as lifting heavy objects, may adjust their understanding of that situation (‘back-stressing tasks are dangerous and can cause pain’) and the behavioral effects (‘avoidance of back-stressing tasks generally reduces pain’) based on the generalization ‘Since back-stressing tasks can cause pain, and avoidance of these tasks generally reduces pain, it is best to avoid such tasks’ .
 Velmans, M. (2000). Understanding Consciousness. London: Routledge/Psychology Press.
 Velmans M. (2001a). A natural account of phenomenal consciousness. Consciousness and Communication, 34(1&2), 39-59.
 Velmans M. (2001b). Heterophenomenology versus critical phenomenology: A dialogue with Dan Dennett. http://cogprints.soton.ac.uk/documents/disk0/00/00/17/95/index.html.
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If mind-brain identity theory is correct, it has great potential to unify our theories of human nature and the universe.
Still, it is not obvious that mental states are identical to brain states. It is difficult to believe that they are one and the same thing.
Reductionism in identity theory causes hard feelings in some philosophers because they feel pressured to abandon their wiggle room, the almost imperceptible space between mind and world where philosophical imagination roams free.
Is mind the same as brain? Consider a pain. Pain is unpleasant, but nowhere in physical space. However, brain states all occur in physical space (the physical brain), and none of them are unpleasant. So pain cannot be identical to any brain-state. Which means mind is not the same as brain. Right?
It is true that what happens in the brain during pain is not itself unpleasant. But, a state of personal pain – a state of experiencing pain, which is always personal – is also not itself unpleasant, and based on neuroscientific evidence, does in fact occur in the brain, likely in insular and cingulate cortices (limbic system).
Pain is a certain state of experience, which we call ‘being in pain’, or ‘having a pain’. When I observe you in pain, I can use the same expressions to characterize your personal experience. So, the word ‘pain’ refers to an experience type, not an object type. A pain is not a weird object felt but not visually apprehended, but a sensory, emotional and cognitive experience, which is unpleasant, hurtful, surreal, burning, throbbing, typically accompanied by injury, and so on.
In migraine headache, being in pain is not located in the head, but a state of migraine is identical to a brain state. Pain is neither an object, nor a thing, but a personal event, and the language of pain may obscure this.
But I think it is correct to say that the painfulness of pain characterizes the appearance of a body-part or bodily portion; in the case of migraine, the apparent location of the migraine directs my attention to my actual head. Note that the phrase ‘appearance of a body-part/bodily portion’ is ambiguous because the phrase also applies to events of pain in body-parts when the apparent body-part referred to does not exist (e.g., phantom pains). Pain locations are qualitative locations.