The following article is based on a presentation made during the
Second International Conference on Integral Psychology,
held at Pondicherry (India), 4-7 January 2001.
The text has been published in:
Cornelissen, Matthijs (Ed.) (2001) Consciousness and Its Transformation. Pondicherry: SAICE.

A map of consciousness studies*

Max Velmans

In ordinary life, first-person accounts of our mental life and actions in terms of what we think, desire, feel, believe, and experience with our senses provide useful explanations of what is going on. Indeed, for most everyday purposes, such accounts are more useful than the more theoretically driven accounts offered by cognitive psychology, neuropsychology and other sciences of the mind. They also provide an initial point of departure for a science of consciousness. In themselves, however, they no more exhaust the scope of a science of consciousness than everyday descriptions of the physical world exhaust the scope of physics. As in physics, a science of consciousness aims for more precise knowledge, deeper understanding, and to discover general truths that can be applied to individual situations (thereby providing a measure of prediction and control). As in any communal science this requires the development of a systematic investigative methodology.

How can one investigate phenomenal consciousness? One cannot do so simply by investigating something other than phenomenal consciousness—even something that relates as closely to it as its neural causes and correlates. As in other areas of science, causes and correlates are not ontological identities.1   That said, there is nothing to prevent a systematic enquiry into how phenomenal consciousness relates to brain processes and to the embedding physical and social world.

This enables one to create a form of “consciousness science” that is already well known and well accepted in psychological research. Psychophysics for example has traditionally investigated how changes in simple dimensions of external physical stimuli (such as intensity and frequency) are translated by perceptual systems into changes in experience. Cognitive psychology investigates the ways in which mental processes operate and how some of these processes (selective attention, working memory, and so on) relate to and support current experience. Neuropsychology tracks the changes in the brain that cause or correlate with normal and disordered forms of experience (see Farthing, 1992, and readings in Velmans, 1996a; Cohen & Schooler, 1997).

Overall this provides a two-pronged approach to consciousness studies in which traditional third-person methods for investigating the brain and physical world are combined with first-person methods for investigating subjective experience with the aim of finding “bridging laws” which relate such first- and third-person data to each other. These traditional routes to the investigation of experience require no a priori commitment to philosophical reductionism (of first- to third-person data). On the contrary, first-person approaches provide data that cannot be obtained from a third-person perspective—for example what it is like to have a given conscious experience or to be in a given conscious state. And third-person approaches provide data that cannot be obtained from a first-person perspective—for example data about what is going on in the brain while one is having a given experience. As I have argued in Velmans (1991a) “first-person and third-person perspectives are complementary and mutually irreducible. A complete psychology requires both.”

There are of course many different ways in which first- and third-person investigations can complement each other. In some situations the relation of first- to third-person data may be very precise. Ordinary conscious states are always of something, so it is plausible to suppose that both they and their neural correlates are representational states. It is also plausible to suppose that given conscious states and their neural correlates encode identical information (about what they represent) although this information may be formatted in very different ways. Consequently, at the interface of consciousness with its neural correlates it may be possible to specify the relation of first- to third-person information with mathematical precision; for example, it may be possible to specify the topology of phenomenal space, the topology of correlated neural representational space, and the mapping of one on to the other.2  

First- and third-person investigations can also be “complementary” in a more general sense. The aetiology of conscious mental states can be investigated both in first-person terms and via third-person methods such as the use of non-invasive imaging techniques that provide real-time information about operations of the brain that correlate with given experiences. First- and third-person approaches can also be mutually supportive in the discovery of unconscious mental states. In other situations the complementary use of first- and third-person information pits interpretations based on first-person data against that obtained via third-person techniques. Here the aim is to find interpretations that most fully account for all the data. Sometimes, third-person data can show first-person theories about the mental states that cause behaviour to be wrong (as in the celebrated studies of folk-psychological beliefs by Nisbett and Wilson, 1977). Conversely, Solms (2000), demonstrates how first-person psychoanalytic investigation of right hemisphere syndrome (a combination of anosognosia, neglect, and defective spatial cognition), can reveal flaws in standard third-person, neurophysiological accounts.

Difficulties in the development of more sophisticated first-person methods

In the study of consciousness, both first- and third-person methods clearly have a role to play. However, given the traditional commitment to “objective” third-person methods in Western science, it is not surprising that these have become far more sophisticated than the so-called “introspective” techniques. Neural imaging studies illustrate this point nicely in that they typically employ impressive machinery with multicoloured displays producing data that can only be analysed with sophisticated statistical techniques. By contrast, the conscious activities and reports required of subjects in neural imaging studies are usually very simple. For example, in studies that investigate the transition from a preconscious to a conscious visual state, subjects might be asked to attend to a simple visual stimulus and to report whether or not they see it. In studies that investigate the processes supporting visual imagery, subjects might be asked to report when they have a visual image (of some object) and so on. In such situations, subjects are asked to enter into or are placed into a given mental state, but the investigation of that state is largely up to the experimenter (using entirely third-person techniques) rather than the subject.

In the early psychological laboratories of Wundt, Titchener and their followers, it was hoped that first-person methods could be developed that are, in their own way, as sophisticated as third-person methods. Although the history of psychological science has shown that this is not easy to achieve, this project was never entirely abandoned, even during the behaviourist years. With the re-emergence of consciousness studies the development of better first-person methods has once again become serious scientific business.3

What are the residual problems? There is more than one map that can be drawn of the consciousness studies terrain—depending on one's direction of approach and the depth and breadth of one's focus. Given this, it is not surprising that both the analysis of problems and the suggested solutions differ. Tart (2000), for example, approaches the problems of consciousness from the perspective of an investigator of altered conscious states. Consequently, he focuses on the need to enter into a given conscious state in order to understand it fully, which opens up the possibility that investigators of consciousness may need to develop a series of “state-specific sciences.” Taking a multidisciplinary approach, Wilber & Walsh (2000) draw a map of the consciousness studies terrain that is as large as the cosmos itself, including its evolution, its microcosm and macrocosm, its individual and social (relational) aspects, and its inner and outer manifestations. This map includes all that we are or can be conscious of. As they make clear, consciousness studies may be divided into distinct domains . Ultimately, all domains support each other (being parts of the whole), but investigative techniques, and the methods of attaining agreement and settling disagreement need to be tailored to the given domain that one wishes to explore. One must choose the map that is most useful for one's purposes for oneself. My own tentative map approaches the terrain with the traditional concerns of an experimental psychologist. Viewed this way, what are the difficulties that first-person methods face? The problems are of three kinds:

1.   Epistemological problems: How can one obtain public, objective knowledge about private, subjective experiences?

2.   Methodological problems: Given that one cannot attach measuring instruments directly up to experiences, what psychological “instruments” and procedures are appropriate to their study?

3.   The relation of the observer to the observed: The more closely coupled an observer is with an observed, the greater the potential influence of the act of observation on the nature of the observed (“observer effects”). Given this, how can one develop introspective and phenomenological methods where the observer is the observed?

Figure 1

Epistemological problems4  

Although the private, subjective nature of conscious experience is widely thought to preclude its scientific investigation. I will argue that this is not where the real problems lie. Rather, the epistemological problems posed by the study of subjective experience are largely artefactual, arising from a misconceived, dualist, splitting of the world which we have inherited from Descartes. This implicit dualism is clearly shown in the model of perception shown in Figure 1. In fact there are two splits in this model: (1) the observer (on the right of the diagram is clearly separate from the observed (the light on the left of the diagram) and (2) public, objective “physical phenomena” in the external world or in the brain (in the lower part of the diagram) are clearly separated from private, subjective psychological phenomena “in the mind” (represented by the cloud in the upper part of the diagram).

How we make sense of this in conventional studies of perception

Following usual procedures, a subject (S) is asked to focus on the light and report on or respond to what she experiences, while the experimenter (E) controls the stimulus and tries to observe what is going on in the subject's brain. E has observational access to the stimulus and to S's brain states, but has no access to what S experiences. In principle, other experimenters can also observe the stimulus and S's brain states. Consequently, what E has access to is thought of as “public” and “objective.” However, E does not have access to S's experiences, making them “private” and “subjective” and a problem for science. This apparently radical difference in the epistemic status of the data accessible to E and S is enshrined in the words commonly used to describe what they perceive. That is, E makes observations , whereas S merely has subjective experiences .

Although this way of looking at things is adequate as a working model for many studies it actually misdescribes the phenomenology of conscious experience—and, consequently misconstrues the problems a study of conscious experience must face. A more accurate model of the way events in the world are experienced by subjects is shown in the reflexive model of perception in Figure 2.

Figure 2

This reflexive model accepts conventional wisdom about the physical and neurophysiological causes of perception—for example, that there really is a physical stimulus in the room that our experience of it represents . But it gives a different account of the nature of the resulting experience. According to this non-dualist view, when S attends to the light in a room she does not have an experience of a light “in her head or brain,” with its attendant problems for science. She just sees a light in a room. Indeed, what the subject experiences is very similar to what the experimenter experiences when he gazes at the light (she just sees the light from a different angle)—in spite of the different terms they use to describe what they perceive (a “physical stimulus” versus a “sensation of light”). If so, there can be no actual difference in the subjective versus objective status of the light phenomenology “experienced” by S and “observed” by E. I have developed the case for this and analysed its consequences elsewhere (Velmans, 1993a, 1996b, 2000). However, one can easily grasp the essential similarities between S's “experiences” and E's “observations” from the fact that the roles of S and E are interchangeable .

A thought experiment—“changing places”

What makes one human being a “subject” and another an “experimenter”? Their different roles are defined largely by differences in their interests in the experiment, reflected in differences in what they are required to do. The subject is required to focus only on her own experiences (of the light), which she needs to respond to or report on in an appropriate way. The experimenter is interested primarily in the subject's experiences, and in how these depend on the light stimulus or brain states that he can “observe.”

To exchange roles, S and E merely have to turn their heads , so that E focuses exclusively on the light and describes what he experiences, while S focuses her attention not just on the light (which she now thinks of as a “stimulus”) but also on events she can observe in E's brain, and on E's reports of what he experiences. In this situation, E becomes the “subject” and S becomes the “experimenter.” Following current conventions, S would now be entitled to think of her observations (of the light and E's brain) as “public and objective” and to regard E's experiences of the light as “private and subjective.”

Notice that this outcome, where the epistemic status of the experienced light switches from “subjective” to “objective” as S switches from being a “subject” to an “experimenter” is absurd, as the phenomenology of the light remains the same, viewed from the perspective of either S or E, whether it is thought of an “observed stimulus” or an “experience.” Nothing has changed in the character of the light that E and S can observe other than the focus of their interest. That is, in terms of phenomenology there is no difference between “observed phenomena” and “experiences.” This raises a fundamental question: If the phenomenology of the light remains the same whether it is thought of a “physical stimulus” or an “experience,” is the phenomenon private and subjective or is it public and objective ?

All experiences are private and subjective.

I do not have direct access to your experiences and you do not have direct access to mine. For example I cannot experience your pain, your thoughts, your colour qualia, the way your body feels to you, the way the sky looks to you, the way I look to you, etc. I can only have my own experiences (however well I empathise). The privacy and subjectivity of each individual's experience is well accepted in philosophy of mind. It seems to be a fundamental given of how we are situated in the world.

In dualism, “experiences” are private and subjective, while “physical phenomena” are public and objective as noted above. However, according to the reflexive model there is no phenomenal difference between physical phenomena and our experiences of them. When we turn our attention to the external world, physical phenomena just are what we experience. If so, there is a sense in which physical phenomena are “private and subjective” just like the other things we experience. For example, I cannot experience your phenomenal mountain or your phenomenal tree. I only have access to my own phenomenal mountain and tree. Similarly, I only have access to my own phenomenal light stimulus and my own observations of its physical properties (in terms of meter readings of its intensity, frequency, and so on). That is, w e each live in our own private, phenomenal world . Few, I suspect, would disagree.

Public access to observed entities and events; public phenomena in the sense of similar, shared, private experiences

What are the implications of this for science? If we each live in our own private, phenomenal world then each “observation” is, in a sense, private. This was evident to the father of operationalism, the physicist P.W. Bridgman (1936), who concluded that, in the final analysis, “science is only my private science”. However, this is clearly not the whole story. When an entity or event is placed beyond the body surface (as the entities and events studied by Physics usually are) it can be perceived by any member of the public suitably located in space and time. Under these circumstances such entities or events are “public” in the sense that there is public access to the observed entity or event itself.

This distinction between the phenomenon perceived by a given observer and the entity or event itself is important. In the reflexive model, perceived phenomena represent things-themselves, but are not identical to them. The light perceived by E and S, for example, can be described in terms of its perceived brightness and colour. But, in terms of physics, the stimulus is better described as electromagnetism with a given mix of energies and frequencies. As with all visually observed phenomena, the phenomenal light only becomes a phenomenal light once the stimulus interacts with an appropriately structured visual system—and the result of this observed—observer interaction is a light as-experienced which is private to the observer in the way described above. However, if the stimulus itself is beyond the body surface and has an independent existence, it remains there to be observed whether it is observed (at a given moment) or not. That is why the stimulus itself is publicly accessible in spite of the fact that each observation/experience of it is private to a given observer.

To the extent that observed entities and events are subject to similar perceptual and cognitive processing in different human beings, it is also reasonable to assume a degree of commonality in the way such things are experienced. While each experience remains private, it may be a private experience that others share. For example, unless observers are suffering from red/green colour blindness, we normally take it for granted that they perceive electromagnetic stimuli with wavelength 700 nanometers (nm) as red and those of 500 nm as green. Given the privacy of light phenomenology there is no way to be certain that others experience “red” and “green” as we do ourselves (the classical problem of “other minds”). But in normal life, and in the practice of science, we adopt the working assumption that the same stimulus, observed by similar observers, will produce similar observations or experiences. Thus, while experienced entities and events (phenomena) remain private to each observer, if their perceptual, cognitive and other observing apparatus is similar, we assume that their experiences (of a given stimulus) are similar. Consequently, experienced phenomena may be “public” in the special sense that other observers have similar or shared experiences.

Being clear about what is private and what is public

The consequences of this non-dualist analysis can be summarised as follows:

—   — There is only private access to individual observed or experienced phenomena .

—   — There can be public access to the entities and events which serve as the stimuli for such phenomena (the entities and events which the phenomena represent). This applies, for example, to the entities and events studied by physics.

—   — If the perceptual, cognitive and other observing apparatus of different observers is similar, we assume that their experiences (of a given stimulus) are similar. In this special sense, experienced phenomena may be public in so far as they are similar or shared private experiences .

From subjectivity to intersubjectivity

This reanalysis of private versus public phenomena also provides a natural way to think about the relation between subjectivity and intersubjectivity . Each (private) observation or experience is necessarily subjective , in that it is always the observation or experience of a given observer, viewed and described from his or her individual perspective. However, once that experience is shared with another observer it can become inter -subjective. That is, through the sharing of a similar experience, subjective views and descriptions of that experience potentially converge, enabling intersubjective agreement about what has been experienced.

How different observers establish intersubjectivity through negotiating agreed descriptions of shared experiences is a complex process that involves far more than shared experience. One also needs a shared language, shared cognitive structures, a shared world-view or scientific paradigm, shared training and expertise and so on. In the process of establishing intersubjectivity, interacting observers can also influence each other's experience and shared understanding of experience in more subtle, interpersonal and social ways to create a shared perspective. This adoption of a shared perspective, from which we see each other and the world is sometimes referred to as “the second person perspective” (see for example, Wilber & Walsh, 2000). We return to this briefly below (in the discussion of “observer effects”). All we need to note for now is that, to the extent that an experience or observation can be generally shared (by a community of observers), it can form part of the database of a communal science.

Different meanings of the term “objective” that are used in science

According to the analysis above, phenomena in science can be “objective” in the sense of intersubjective. Note, however, that intersubjectivity requires the presence of subjectivity rather than its absence. Observation statements (descriptions of observations) can also be “objective” in the sense of being dispassionate, accurate, truthful, and so on. Scientific method can also be “objective” in the sense that it follows well-specified, repeatable procedures (perhaps using standard measuring instruments). However, if the analysis above is correct, one cannot make observations without engaging the experiences and cognitions of a conscious subject (unobserved meter readings are not “observations”). If so, science cannot be “objective” in the sense of being observer-free.

Intra-subjective and inter-subjective repeatability

According to the reflexive model, there is no phenomenal difference between observations and experiences . Each observation results from an interaction of an observer with an observed. Consequently, each observation is observer-dependent and unique . This applies even to observations made by the same observer, of the same entity or event, under the same observation conditions, at different times —although, under these circumstances, the observer may have no doubt that he/she is making repeated observations of the same entity or event.

If the conditions of observation are sufficiently standardised an observation may be repeatable within a community of (suitably trained) observers, in which case intersubjectivity can be established by collective agreement . Once again, though, it is important to note that different observers cannot have an identical experience. Even if they observe the same event, at the same location, at the same time, they each have their own, unique experience. Inter subjective repeatability resembles intra subjective repeatability in that it merely requires observations to be sufficiently similar to be taken for “tokens” of the same “type.” This applies particularly to observations in science, where repeatability typically requires intersubjective agreement amongst scientists observing similar events at different times and in different geographical locations.

Consequences of the above analysis for a science of consciousness

The above provides an account of the empirical method, i.e. of what scientists actually do when they test their theories, establish intersubjectivity , repeatability and so on which accepts that observed, physical phenomena just are the entities and events that scientists experience. Although I have focused on physical events, this analysis applies also to the investigation of events that are usually thought of as “mental” or “psychological.” Although the methodologies appropriate to the study of physical and mental phenomena may be very different, the same epistemic criteria can be applied to their scientific investigation. Physical phenomena and mental (psychological) phenomena are just different kinds of phenomena which observers experience (whether they are experimenters or subjects). S1 to n might, for example, all report that a given increase in light intensity produces a just noticeable difference in brightness, an experience/observation that is intersubjective and repeatable. Alternatively, S1 to n might all report that a given anaesthetic removes pain or, if they stare at a red light spot, that a green after-image appears, making such phenomena similarly public, intersubjective, and repeatable.

  Figure 3

This closure of psychological with physical phenomena is self-evident in situations where the same phenomenon can be thought of as either “physical” or “psychological” depending on one's interest in it. At first glance, for example, a visual illusion of the kind shown in Figure 3, might seem to present difficulties, for the reason that physical and psychological descriptions of this phenomenon conflict.

Physically, the figure consists entirely of squares, joined in straight lines, while subjectively, most of the central lines in the figure seem to be bent. However, the physical and psychological descriptions result from two different observation procedures. To obtain the physical description, an experimenter E typically places a straight edge against each line, thereby obscuring the cues responsible for the illusion and providing a fixed reference against which the curvature of each line can be judged. To confirm that the lines are actually straight, other experimenters (E1 to n) can repeat this procedure. In so far as they each observe the line to be straight under these conditions, their observations are public, intersubjective and repeatable.

But, the fact that the lines appear to be bent (once the straight edge is removed) is similarly public, intersubjective and repeatable (amongst subjects S1 to n). Consequently, the illusion can be investigated using relatively conventional scientific procedures, in spite of the fact that the illusion is unambiguously mental . One can, for example, simply move the straight edge outside the figure making it seem parallel to the bent central lines—thereby obtaining a measure of the angle of the illusion.

The empirical method

In short, once the empirical method is stripped of its dualist trappings, it applies as much to the science of consciousness as it does to the science of physics, and it applies both to Western phenomenological methods, focused on ordinary conscious states and to methods for investigating altered states, such as those developed in the East. It also applies to the evaluation of processes for changing experience.

Stated formally, the empirical method follows one, fundamental principle:


   — If observers E1 to n (or subjects S1 to n ), carry out procedures P1 to n , under observation conditions O1 to n , they should observe (or experience) result R


(assuming that E1 to n and S1 to n have similar perceptual and cognitive systems, that P1 to n are the procedures which specify the nature of the experiment or investigation, and that O1 to n includes all relevant background conditions, including those internal to the observer, such as their attentiveness, the paradigm within which they are trained to make observations and so on).

Or, informally:


   — If you carry out these procedures you will observe or experience these results. 5

Complicating factors: symmetries and asymmetries of access.6

Investigations of consciousness do, of course, face domain-specific problems, which are different to those typically encountered in investigations of the external world. These differences arise partly from differences in the questions of interest, partly from differences amongst some of the phenomena studied and partly from systematic differences in the typical access an observer has to the observed.

For experimental purposes, the entities and events studied by physics are located external to the observers. Placed this way, such entities and events afford public access (see above) and different observers establish intersubjectivity, repeatability and so on by using similar exteroceptive systems and equipment to observe them. E and S in Figure 2, for example, might observe the light via their visual systems, supplemented by similar instruments that measure its intensity, frequency and other physical properties. When S and E (and any other observer suitably place in space and time) use similar means to access information about a given entity or event we may say that they have symmetrical access to the observed (in this case, to the stimulus light itself). If the event of interest is located on the surface of or within S's body, or within S's brain, as would be the case in the study of physiology or neurophysiology, it remains external to E. Thus placed, it can still afford public, symmetrical access to a community of other, suitably placed external observers (E1 to n ). Consequently, such events can be investigated by the same “external” means employed in other areas of natural science.

In the study of consciousness, however, what the subject observes or experiences is of primary interest and, if one compares the information about S available to S with the information about S available to E (and other external observers), various forms of asymmetry arise. If the event of interest is located on the surface of or within S's body, she may be able to observe or experience that event through interoceptive as well as exteroceptive systems. For example, if she stabs her finger with a pin she might not only be able to see the pin go in, but also to experience a pain in her finger consequent on skin damage. Under these circumstances, she has two sources of information about the event taking place in her skin, while E retains only exteroceptive (visual) information about this event, as before. Likewise, if one stimulates S's brain with a microelectrode, she might, like E, be able to observe the electrical stimulation (with an “autocerebroscope”7 ). But, in addition, she might be able to experience the effects of such stimulation in the form of a consequent visual, auditory, tactile or other experience. In such situations, observers E and S have asymmetrical access to the observed.

Crucially, E and S (and any other observers) have asymmetrical access to each other's experiences of an observed (asymmetrical access to each other's observed phenomena). That is, they know what it is like to have their own experiences, but they can only access the experiences of others indirectly via their verbal descriptions or non-verbal behaviour. This applies to all observed phenomena, for example, it applies even if the observed is a simple physical stimulus, such as the light in Figure 2. As E does not have direct access to S's experience of the light and vice-versa, there is no way for E and S to be certain that they have a similar experience (whatever they might claim). E might nevertheless infer that S's experience is similar to his own on the assumption that S has similar perceptual apparatus, operating under similar observation arrangements, and on the basis of S's similar observation reports. S normally makes similar assumptions about E. It is important to note that this has not impeded the development of physics and other natural sciences, which simply ignore the problem of “other minds” (uncertainty about what other observers actually experience). They just take it for granted that if observation reports are the same, then the corresponding observations are the same. The success of natural science testifies to the pragmatic value of this approach.

Given this, it seems justifiable to apply the same pragmatic criteria to the observations of subjects in studies of consciousness (i.e. to their “subjective reports”). If, given a standard stimulus and standardised observation conditions, different subjects give similar reports of what they experience, then (barring any evidence to the contrary) it is reasonable to assume that they have similar experiences. Ironically, psychologists have often agonised over the merits of observation reports when produced by subjects, although like other scientists, they take them for granted when produced by experimenters, on the grounds that the observations of subjects are “private and subjective,” while those of experimenters are “public and objective.” As experimenters do not have access to each other's experiences any more than they have access to the experiences of subjects, this is a fallacy, as we have seen. Provided that the observation conditions are sufficiently standardised, the observations reported by subjects can be made public, intersubjective, and repeatable amongst a community of subjects in much the same way that observations can be made public, intersubjective and repeatable amongst a community of experimenters. This provides an epistemic basis for a science of consciousness that includes its phenomenology.

In sum, asymmetries of access complicate, but do not prevent the investigation of experience. In Figure 2, E has access, in principle, to the events and processes in S's visual system, but not to S's experience. While S focuses exclusively on the light, she has access to her experience, but not to the antecedent processing in her visual system. Under these circumstances, the information available to S complements the information available to E. As noted earlier, to obtain a complete account of visual perception one needs to utilise both sources of information.

Methodological problems

It goes without saying that the empirical method, formulated in this way, provides only basic, epistemic conditions for the study of consciousness. One also requires methodologies appropriate to the subject matter—and the methodologies required to study conscious appearances are generally very different from those used in physics. There are many ways in which the phenomena we usually think of as physical or psychological differ from each other and amongst themselves (in terms of their relative permanence, stability, measurability, controllability, describability, complexity, variability, dependence on the observational arrangements, and so on). Even where the same phenomenon is the subject of both psychological and physical investigation (as might be the case with the light in Figure 2 above) the interests of psychologists and physicists differ, requiring different investigative techniques. A physicist, for example, is typically interested in the nature of the light as such, characterised for example in terms of the quantum mechanical properties of its constituent photons. Psychologists are more interested in how such physical energies are translated by the visual system into phenomenal appearances, for example in the ability of the visual system to translate changes in light intensity and frequency into discriminable changes in brightness and colour. Unlike entities and events themselves, one cannot hook measuring instruments up to conscious appearances. For example, an instrument that measures the intensity of the light in Figure 2 (in lumens) cannot measure its experienced brightness. Given this, one needs some method of systematising subjective judgements and consequent reports, for example, by recording minimal, discriminable differences in brightness, in the ways typically used in psychophysical experiments. 8

The need to translate observations into observation reports also occurs, of course, in natural science, although here, reports are often made precise through the use of measuring instruments (which can be hooked up to the observed entities and events themselves). In some cases, a mental phenomenon can also be “measured”, in spite of the fact that the only observer with access to that phenomenon is the subject. It is standard practice, for example, to measure the size of a visual illusion by requiring subjects to adjust the dimensions of an external, comparison stimulus so that it matches the dimensions of the illusion (see, e.g., the discussion of the illusion shown in Figure 3 above).

That said, not all phenomena of interest to consciousness studies are easy to measure or even to communicate in an unambiguous way. Some experiences are difficult to translate into words, and therefore into subjective reports. Images, for example, generally lack the clarity, vividness and relative permanence of events as experienced out in the world, which may make them difficult to describe with accuracy and precision. Consequently, indirect measures of imagery such as its effects on memory, learning, perception and so on are common in imagery research.9   Difficulties may also arise because one does not have a vocabulary adequate to communicate some experience unambiguously. Most human beings know what it is to love or be angry, but the many nuances of such experience are more difficult to describe (the differences in the feeling of the love of wild places, love of one's child, love of one's lover, love of the truth, love of life, compassionate love, and so on). Investigators typically deal with such situations by developing new typologies and descriptive systems (as with the typologies developed for the chemical sense modalities, taste and smell). The way experiences are categorised into types and the extent to which given categories are differentiated in ordinary language are also, in part, culture-specific. English, for example, has a highly differentiated colour terminology (consequent on the development of pigments and dyes) whereas the language of the Dani tribesmen of New Guinea has only two colour terms (“mola” for warm, light colours and “mili” for dark, cold ones). In such situations, investigators can bypass linguistic differences by using non-verbal responses—measuring, say, colour discrimination or memory by requiring subjects to visually match target colours with comparison colours on a colour chart.

These brief points about methodological problems and some of the ways that they are commonly addressed will be familiar to those trained in psychological research. Psychology and its sister disciplines have developed many different methodologies for investigating sensation, perception, emotion, thinking, and many other areas that deal directly or indirectly with how phenomena are experienced. However, as the chapters in this book demonstrate, there is much more to be said about this subject and still much to be done.

The relation of the observer to the observed.

Observations in science or in ordinary life are, to varying degrees, dependent on the relation of the observer to the observed. The very act of observation can affect the nature of the observed although the strength of this effect depends on the strength of the observer/observed coupling. As Norbert Wiener (the father of cybernetics) pointed out, in classical physics the observer and the observed are, in general, “loosely coupled” and the effects are relatively small (although one still has to take account of the effect of one's measuring equipment on what is being measured). In psychology, when the observed is another human being, the observer and observed are often “closely coupled” which can produce a range of “experimenter effects.” In traditional experimental psychology, as in physics, care is taken to control for such effects. Experimenters might place themselves in a different room to the subject, take care to be non-invasive, give non-leading instructions, and so on.

However, in consciousness studies the effect of relationship on experience can itself be a topic of considerable interest. By what process of mutual influence, for example, do we make the transition from first- to second-person perspectives? How does the private, subjective, phenomenal world (which “I” inhabit) become the shared, intersubjective world (which “we” inhabit)? And how does the intersubjective world of “we” have enduring effects on the private world of “me.” Individual experience is also shaped by its broader social and cultural context. This provides another rich field of study, as the full effects of such embeddings are not well understood. Individual relationships also vary in their “quality” with potentially potent effects on the participants. Henry (2000), for example, reviews evidence that the quality of relationship between therapist and client is a major determinant of change in clients' experience. And, Richardson (2000) examines ways in which different forms of intersubjectivity established in clinical practice contribute to a “therapeutic relationship.” A detached versus an engaged clinician-client relationship, for example, may have very different consequences for what can be revealed or expressed in therapeutic encounters, which can have powerful effects on health outcome and well being. But what determines the quality of relatedness? How, for example, can one move from isolation to communication, intersubjectivity, empathy, and intimacy?

The relation of the observer to the observed is most intimate, of course, in situations where the observer is the observed, for example, in the use of introspective and phenomenological methods where subjects become the primary investigators of their own mental processes and states. In this situation “observer effects” seem to be unavoidable. The very act of directing one's attention to one's own mental states affects those states, for the simple reason that the direction and quality of attention itself defines a state of mind. Once one adds the problems of self-description, self-analysis, and self-interpretation (of mental states) it is little wonder that some authors despair of ever developing a systematic, introspective science.

However, other authors suggest that it is possible for the mind to become sufficiently stable to attain a deeper first-person knowledge of its own nature, uncovering states and processes that can be confirmed by an appropriately trained research community. Such investigative techniques often encourage a dispassionate, focused but open attitude to whatever emerges in experience (noticing whatever emerges without grasping, avoiding, judging, and so on). Depraz et al. (2000), for example, give a detailed description of a first-person investigative method that requires a “phase of suspension of habitual thought and judgement”, a “phase of conversion of attention from the exterior to the interior” and “phase of letting go or receptivity towards the experience.” Various readings in The View From Within (see note 3) illustrate how this method (augmented by other techniques) can be applied in practice. For example, an investigation of intuition by Petitmengen-Peugeot (1999) revealed the states of mind preparatory to having creative insights in a sufficiently detailed form to provide a basis for making predictions about how to facilitate such states. And Varela (1999) demonstrates how a detailed phenomenological exploration of the experience of time can provide first-person accounts that can be related to sophisticated models of the brain's temporal processing. Needless to say, the application of such subtle introspective methods requires careful training (a common situation in science)—in this instance, training in how to enter into an appropriately receptive state of mind. This may be an example of the “state-specific sciences” suggested by Tart, as only those researchers who can enter into the appropriate states of mind can confirm or disconfirm the findings. It is important to note however that the utility and productiveness of such research methods can be assessed in the normal way, in terms of whether they enable prediction, control, provide a more integrated understanding of the phenomena under investigation, and so on. For example, Petitmengen-Peugeot's findings on states conducive to creativity can be evaluated in terms of whether others trained to enter into such states really do become more creative. And Varela's findings on the phenomenology of experienced time may be supported (or not) by triangulating evidence about temporal processing in the brain.

It should be clear that in the application of such phenomenological methods, changing the state of mind of the observer becomes an unavoidable part of the investigation. Conversely, another traditional purpose of self-investigation is to effect change, for example in the therapeutic and clinical situations reviewed by Henry (2000) and Richardson (2000). In discovering its own nature, the mind changes its nature. This process too, may follow discoverable, systematic principles—and it may be that in this, consciousness studies in Western science has a good deal to learn from traditional first-person investigative methodologies that have been developed over the millennia with aim of inducing such changes, particularly in the East.


There are many maps that can be drawn of consciousness studies. But from the perspective of psychological science, the difficulties posed by the study of consciousness may be categorised into epistemological problems, methodological problems, and problems that follow from the potential effects of the observer on the observed.

It has traditionally been thought that one cannot make consciousness studies into an “objective” science on the grounds that one cannot obtain public, objective knowledge about private, subjective experiences. However, all science relies on the experiences/observations of scientists. Scientists can be “objective” in the sense of being dispassionate, employ procedures that are “objective” in the sense of being well specified and repeatable, and develop “objective knowledge” in the sense of intersubjective knowledge. But no observations in science are “objective” in the sense of being observer-free. Nor does science require “observer-free observations.” The heart of science is the empirical method which, simply put, is if you follow these procedures you will observe or experience these results . This applies as much to a science of consciousness as it does to physics.

No science of consciousness can be complete without first-person methods. Although existing first-person methods can be combined with third-person methods in a variety of useful, complementary ways, there is a clear need to develop more sophisticated first-person methods, particularly for those aspects of experience that are relatively complex, impermanent, unstable, or variable, or are difficult to describe, measure, or control. As with any area of investigation, the investigative tools and procedures need to be tailored to the phenomena under study. While there is a great deal of methodological development to be done, particularly in less well-articulated domains of experience, such development is standard practice in psychological science.

Within consciousness studies, there are many situations where the very act of observation can change the observed. These “observer effects” take two forms: The way an external observer relates to an experiencing subject can alter his or her experience (“experimenter effects”). With introspective methods where the observer is the observed, the act of introspection already produces a change in the operations of the mind.

Depending on one's purposes, there are two basic ways of dealing with such effects: one can attempt to minimise them, or study and harness them. Techniques for minimising observer effects in the study of other people all hinge on “removing” the observer (in some sense) from the observation—either literally, by placing the observer in a separate room, or metaphorically, by being non-invasive, giving non-directive instructions, etcetera. While self-observation techniques cannot remove the observer, they often encourage a dispassionate, focused, but open attitude to whatever emerges in experience (noticing whatever emerges without grasping, avoiding, judging, and so on).

For other purposes, the way that relationship changes experience is itself of primary interest. The experiences of individual observers are embedded in interpersonal, social and cultural contexts, requiring continuous re-negotiation of the borders between the first-person space of “I” and the second-person space of “we”. The transitions between subjectivity and intersubjectivity are complex and not fully understood. The effects of different forms of self-investigation on the contents of consciousness are similarly obscure. Such observer/observed interactions become particularly important when the deeper purpose of the investigation is to transform experience rather than to describe it, analyse it or theorise about it. How different forms of engagement with others or oneself might facilitate such change is an important topic for research.

It has to be said that the methodological problems are sometimes complex and the solutions sometimes controversial, particularly in the use of introspective and phenomenological methods where subjects become the primary investigators of themselves. But this does not alter the fact that the phenomena of consciousness provide data that are potentially public, intersubjective and repeatable. Consequently, the need to use and develop methodologies appropriate to the study of such phenomena does not place them beyond science. Rather, it is part of science.



1   If consciousness could be demonstrated to be nothing more than a state or function of the brain it would be possible to study consciousness by studies of the brain alone. I have summarised some of the fallacies of such reductionism in Velmans (1998) and reviewed these in depth in Velmans (2000), so I will not repeat this analysis here.

2   Following this theoretical approach, phenomenal and neural-state “spaces” are dual aspects of a form of mental information, and their very different phenomenal and neural formats arise from the different first- versus third-person perspectives from which that information is viewed. In some respects (but not others) this is analogous to wave-particle complementarity in quantum mechanics where the wave- or particle-like nature of photons depends entirely on the measuring arrangements, and where a complete description of photons requires both wave and particle accounts. A more detailed analysis of such “psychological complementarity”, is given in Velmans (1991a, section 9.3, 1991b, sections 8 and 9, 1993a, 1996c, and 2000, chapter 11). Some aspects of this position have also been adopted by Chalmers (1995) and Maclennan (1996) (see the commentary on Chalmers in Velmans, 1995).

3   See readings in Pope & Singer (1978), the View From Within an entire issue of The Journal of Consciousness Studies , 6, 2/3, 1999, and the on-line course and discussions of “The Investigation of Conscious Emotion: Combining first- and third-person methodologies.” Sponsored by the University of Arizona at Tucson and the Journal of Consciousness Studies , February to March, 1999.

4   The following analysis of epistemological problems is largely taken from Velmans (1999).

5   It is interesting to note that Tart (2000), and Wilber & Walsh (2000) arrive at a very similar conclusion.

6   The following analysis is taken largely from Velmans (2000), chapter 8.

7   A hypothetical machine for viewing activity in one's own brain, e.g. via a T.V. monitor attached to sensors which detect electrical, magnetic or other activity.

8   To clarify the epistemic issues, I have so far focused only on very simple cases of conscious experience (simple visual percepts, pains and so on) which are relatively easy to study and control. Under normal conditions, for example, visual perception appears to be so tightly guided by the information picked up by the retina that the resulting experience gives every appearance of being a “direct perception” of what is out-there in the world. Consequently, given similar stimuli, presented under similar viewing conditions, with similar expectations, experimental instructions and so on, different subjects are likely to agree that they see the same thing. By contrast, experienced thoughts, emotions and images are largely determined by endogenous factors, and even when they are influenced by events in the external world, they generally represent some inner response to external events, rather than representing the events themselves. This makes them heavily dependent on individual differences in heredity, personal history, momentary fluctuations in attention and interest, and on other endogenous factors, making them less easy to reproduce under controlled conditions. Other experiences may be rare or even unique to the individuals involved. While these factors complicate investigation they do not prevent it. Psychologists simply include such complicating factors within their research—investigating the effects of heredity, learning, and attention on thinking and emotion, making use of single case studies where needed and so on. In some studies investigators harness subjects' ability to control their own experience. A common method of studying imagery for example is to ask subjects to generate a given image, and then to perform some task that reveals something about its nature or use. When a given experience is very difficult to reproduce at will, it can be investigated when it occurs naturally, as in studies of dreaming during REM sleep. As in natural science, the accuracy of reports can become suspect when stimuli or experiences are near the limits of detectability, for example, when a weak signal is embedded in noise—in which case estimation procedures have to be developed, such as those suggested by signal detection theory. One also has to be mindful of the well-known effects of the act of observation on the nature of the observed. Such “experimenter effects” have been extensively investigated in psychology (along with the means by which they can be minimised), but they can be particularly powerful when the observer is the observed, for example, when a subject studies (rather than simply reports on) her own conscious experience. In such cases one either has to attempt to limit such influences (cf Ericsson & Simon, 1984) or to harness them, for example in situations where focused self-observation is intended to transform conscious states rather than to describe them (see below).

9   A useful review of current methods for investigating imagery is given by Richardson (1999).


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*   — This paper is adapted from Velmans, M (2000) “A psychologist's map of consciousness studies”, in M. Velmans (ed.) Investigating Phenomenal Consciousness: New Methodologies and Maps. Amsterdam: John Benjamins.