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The Science of Consciousness: Where It is and Where It Should Be





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A review of Antti Revonsuo’s Inner Presence: Consciousness as a Biological Phenomenon 7 x 9, 440 pp., 30 illus. MIT Press ISBN 0-262-18249-1 This excellent book is aptly titled. It presents a closely argued analysis of the current state of consciousness studies and suggests a strategy of investigation, which the author believes is necessary to […]

Posted March 10, 2007 by Bernard J. Baars

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A review of Antti Revonsuo’s Inner Presence: Consciousness as a Biological Phenomenon

7 x 9, 440 pp., 30 illus.
MIT Press
ISBN 0-262-18249-1

This excellent book is aptly titled. It presents a closely argued analysis of the current state of consciousness studies and suggests a strategy of investigation, which the author believes is necessary to establish a robust science of consciousness. Before he introduces the details of his framework for a unified science of consciousness, Revonsuo makes the following broad assertions:

  1. The field of consciousness research is far from being a true science because it lacks a unified research program.
  2. A proper unified research program should fall within the conceptual and procedural framework of biological realism wherein explanations of conscious phenomena are expressed mainly in the terms of cognitive neuroscience.
  3. Understanding of consciousness must be based on understanding the multilevel biological mechanisms which explain how conscious phenomena work.

Revonsuo conceptualizes consciousness as the phenomenal level of organization in the brain. The fundamental questions to be answered by a proper science of consciousness are best stated in his own words.

How does the phenomenal level relate to other levels of organization in the brain? How could the phenomenal level be measured or observed empirically? How could it be conceptualized or modeled theoretically? What are the causal powers of entities and properties residing at the phenomenal level of organization?

Moreover, lest there be any doubt about his commitment to a completely biological explanation of conscious content, he makes the following statement.

According to biological realism, since consciousness is a biological level of organization in the brain, it follows that the structure of neurobiological phenomena, at some higher level of physiological organization and description, corresponds to the structure of the phenomenal level or consciousness itself. Thus, for example, a visual experience consisting of complex patterns of form and color necessarily implies a phenomenon of corresponding complexity and organization in the brain.

If we take his statement at face value, it appears that Revonsuo agrees with the strong claim that the contents of consciousness can only exist as manifestations of their corresponding physiological analogs in the brain. Notice that this, contra the mainstream paradigm, rules out mere neuronal correlates as candidates for the phenomenal level of organization in tne brain.

The first three sentences in the summary at the end of Chapter 9, provide the essence of Revonsuo’s claim that a simulation within the brain of the space around us creates the setting for the inner presence which, in his view, constitutes our phenomenal experience. These sentences deserve to be quoted directly.

Empirically based phenomenology should be built on a model that takes the spatiality and centeredness of consciousness as its fundamental structural and organizational property. The phenomenal level is based on an egocentric, bounded coordinate system whose regions can instantiate qualitative features. When that coordinate system is present in the brain, the brain is in the conscious state (i.e., capable of realizing phenomenal contents); when it is absent, the brain is in an unconscious state (i.e., incapable of realizing phenomenal contents).

Revonsuo is absolutely correct in his call to develop theories of the biological mechanisms that are competent to generate the brain events that constitute our phenomenal experience, but I do not agree with his contention that no such theory exists today.After setting these minimal requirements for the evocation of the phenomenal level, Revonsuo next addresses the kinds of processes needed to provide the brain’s egocentric spatial coordinate system with its properly bound, segregated, and synchronized feature-rich contents. He believes that the major aspects of phenomenal consciousness such as selective attention, feature integration and, most important, the simulation of a world and a self, may depend on neuronal synchronicity but that investigators have yet to offer a clear picture of what might be going on the brain when this happens. From a neuroscience perspective, we should go beyond the search for neural correlates of consciousness and and look for the constitutive mechanisms of consciousness. According to Revonsuo, we should seek brain mechanisms that can provide a coherent master gestalt composed of what he calls “Gestalt windows” within an egocentric spatial coordinate system that can be independently accessed, tagged, and interactively coupled with “semantic windows” (semantically categorized Gestalt windows). Although these essential processes are only nominally described black boxes, this is the general scheme of what he believes we should be looking for. The task is to specify the brain mechanisms that can do the job. While Revonsuo argues that the explanation of consciousness requires theories developed within the framework of a biologically naturalized mechanistic approach, he claims that there are no such theories to be found today. In my view, Revonsuo is absolutely correct in his call to develop theories of the biological mechanisms that are competent to generate the brain events that constitute our phenomenal experience, but I do not agree with his contention that no such theory exists today. I will return to this point later.

Because sensory input does not modify phenomenal consciousness during sleep, for Revonsuo, the content of dreams is, in effect, an existence proof that consciousness is encapsulated within the brain. He therefore stresses the dreaming brain as particularly important for the study of consciousness, and buttresses this claim by his conjecture that dreaming has evolutionary utility as a biological defense system in which the dreaming brain simulates threatening situations in order to enhance survival.

Returning to the overarching theme in Inner Presence, if we are to explain consciousness we must expose the neuronal mechanisms which constitute consciousness rather than the mere neural correlates of consciousness. Features at the phenomenal level — the patterns, organization and dynamics of subjective experience — are to be explained by the structure and dynamics of their underlying constitutive biological mechanisms and systems. According to Revonsuo, the brain mechanisms of consciousness must possess at least the following characteristics:

  1. Integration into one overall coordinate system
  2. Rapid temporal reorganization
  3. An internal center-surround structure, involving the interplay between phenomenal consciousness, selective attention, and reflective consciousness
  4. A vast combinatorial capacity

What would a proper brain model of the phenomenal level look like? Here is Revonsuo’s criterion: “A model of the phenomenal level is a model of a system in the brain that itself models or images the world, by constructing organized patterns of phenomenal features and by opening the corresponding semantic windows. A mechanistic model of the phenomenal level is, therefore, a model of a world-modeling system in the brain .” Moreover, he claims “It is possible to observe or model the phenomenal level only from the egocentric perspective from which it is experienced.”

If we grant the cogency of Revonsuo’s criteria for a model of the phenomenal level (which I do) then the challenge is to explicate the minimal design of biologically plausible brain mechanisms and systems that can do the job. Is there a current theory that meets his demands? Namely, do we now have any mechanistic models of an egocentric world-modeling system in the human brain?

Revonsuo offers us an admirable book, not only in its comprehensiveness and careful analysis of the current field of consciousness studies, but also for its emphasis on what I concur are the core criteria of conscious experience, as well as presenting a promising strategy for future exploration.I think The Cognitive Brain (TCB), MIT Press, 1991, provides such a model. In this book, I have presented a large-scale neuronal theory of the cognitive brain that includes, as an essential mechanism, what I have called the retinoid system. The structural and dynamic properties of the retinoid system enable it to register and appropriately integrate disparate foveal stimuli into a perspectival, egocentric representation of an extended 3D world scene including a neuronally-tokened locus of the self. The self-locus serves as the neuronal origin of phenomenal (retinoid) space (see TCB, Ch. 4 “Modeling the World, Locating the Self, and Selective Attention: The Retinoid System”). In addition, the extended TCB model includes specified mechanisms for learning and recalling images of objects and their spatial layouts as organized patterns of features (“gestalt windows”) within the egocentric coordinates of retinoid space. Moreover, interactive semantic processing mechanisms are described in detail (see for example TCB, Ch. 6 “Building a Semantic Network”). These are capable of evoking what Revonsuo calls “semantic windows” in proper relationship to their corresponding gestalt windows. In my opinion, the close agreement between the neuronal models detailed in The Cognitive Brain and the recommendations in Inner Presence give added weight to Revonsuo’s proposals.

In summary, Revonsuo offers us an admirable book, not only in its comprehensiveness and careful analysis of the current field of consciousness studies, but also for its emphasis on what I concur are the core criteria of conscious experience, as well as presenting a promising strategy for future exploration. I believe Inner Presence should be on the reading list of anyone interested in phenomenal experience as a scientific problem.

Bernard J. Baars



    Rodrick Wallace

    A formal, information-theoretic, description of something which seems much like a ‘retinoid’ model can be found in a new paper:


    The essential structure is a simplified, but inherently tunable, tangent space to a complicated manifold in which the mapping is defined in terms of the rate distortion theorem. Under proper tuning, relatively little information is lost, although poor tuning can lead to quite spectacular inattentional blindness.


    First of all thank you Alic for the way you presented this article. As for the author’s notion that consciousness is in the brain, I can without hesitation ‘concur’, however the idea implied in the term “encapsulated” may need reconsideration by him. One sentence more: The area in which the author concentrates his researches on consciousness is quite pertinent. Good luck.


    I think phenomenon are known via relations derived from self relation as in the example given below using the onion (its’ layers, are alone, prominent demarcations perhaps related in the same way to the organization assortment and extraction of learned facts)

    I am a scientist (biochemist) absent from the university 20 years and have recently pursued a study in philosophy. Current science education is very restrictive and does not consider history. In my own mind I have reduced all things(including cause and effect) to the word witness(of both unique witness A and the act of his(its’) witness =A). From this scheme A chain is thus described of witness and events A.B.C.D …over time of any change.. This must be true even for temporally unextended events. A question can be posed-can a volume of space exist that is closed such that a witness process within it leaves no external record from uncommunicated thought, and I do not think that this is possible. Between the past and the present, in general, the existence of a closed space implies the alignment of all witness processes from an origin. Thus if the molecular interactions within the brain are chains of witness in terms of communications between intracellular and extracellular events, thought produces a sum change of some type, rather than saying A causes B. Like the layers of an onion, it is conceived from a (differential-i.e conceived from a more previous change)..previous change.. and relates to itself that way…relates externally that way the same, and to the same, of objects of mutual witness and cannot be detected if it did not occur in this ad-infinitum means of mutual relation . .e.g. occurred with intention as an external relation appropriate to the relations of another onion-set of onion like, layered entity. If such a relation did not occur, it did not exist; the suggestion of whether an uncommunicated thought/unextended event, could be detectable is not any different from the suggestion of being able to detect what dies niot exist. This is very different from a notion “does cognition alone produces detectable or undetectable change”. The way one spends his time, where his thoughts rest can change the way he relates–self-relates. I think this fact might be instantiated to concepts of history.
    With respect to the onion example, the world, all of its’ processes might be divided into the appropriate (direct, basically originating proximally, and directly applicable to one’s perceptions) and the inappropriate (indirect, originating distal to what is proximal and relocated in the sense that it contains “information” more applicable to a distal place). These elements –appropriate and inappropriate, associated with momentum/energy-by comparison and difference, I believe, define time, are the perceived elements of change, as of the different layers of the onion-and the basis of all relations. Actual time itself I think to be of a higher order(e.g. x^2) oscillation, with respect to our mental frequencies/wavelengths as space and volume seekers; are but a subset. Einstein himself did not believe that the correct elements to describe phenomenon had been ascertained (major topics being “observed and then reconsidered”).
    If one reflects on history, it is dominated (from description see Nietzsche “On the Geneology of Morals) ) to be riddled with actions and concepts formed from inappropriate connections(the Arians and the Jews and their described activities and ascribed life positions with respect to others-one another).

    To include the human habit of soul searching, but extended deep into the realms of science and philosophy, where serious controversies exist and a vast dark area continues to emerge, I would like to propose the notion that there is an inappropriate light in every beacon on this earth from its’ beginning –from the first recorded thoughts.
    With respect to history and science, it is simple to state that all things emerge, but not so simple to accept that we might not find laws that enable us to assemble an understanding or order to provide explanation-but only a simple list of circumstances evolved over time from the past and unwitnessable. I believe that natures mechanism for continuance is recurring in the sense that (information for) survival in (innately) included with conscious experience. Science, though, appearing useless, in this case of unpredictable emergence, might only suffer from a poor orientation(see personal manuscript in URL list) in its avoidance, or ignorance, of individual ratios (that might be, with empirical categorization, become individual potential ratios, for each unique,causality becoming, in both science and individual perception a range of hierarchically ordered potentials uniquely suited for each unique relation). A newly ordered scheme that accounts only for a mechanism of transmission, transmission/replication of form, self avoidance as the issuer of force/momentum-the means of uniqueness(and uniqueness in perspective and emergence), is possible. In this sense though, I believe/fear that we have overextended our means to take an inappropriate direction for continuance with an excessive exploitation of nature arrived at from failed insight and overconfidence.

    Marvin E. Kirsh



    douglas seyfried

    If physicists can recognize that there is no physical explaination for all phenomena and produce the most valid scientific theory in history (quantum mechanics) why must consciouness researchers tie themselves to a philosophy (materialism) that has been shown to be false by the best science we have?


    Re comment #6, while quantum mechanics has proven useful as a formalism for sub-atomic events, so far there has been no evidence that QM can explain consciousness or its phenomenal content. It is interesting to note that Feynman stated that neither he nor anyone else really *understands* quantum mechanics (see Feynman, 1988, *QED*, Introduction, p. 9). On the other hand, neuroscientific principles and theoretical mechanisms are able to explain and predict significant details of phenomenal experience (e.g., the retinoid model).

    Arnold Trehub


    Douglas Seyfried makes an excellent point in comment #6. I have noticed that philosophers are still talking about the “problem” of determinism versus free will, even though quantum mechanics long ago killed determinism dead. (And yes, quantum phenomena can magnify up to a macroscopic scale; as radiation sickness and genetic mutations due to cosmic rays prove.) So there seems to some reluctance among philosophers to take quantum theory seriously at its face value, even though it’s now about a hundred years old, and one of the best confirmed theories in the history of science.

    I have to wonder if this is not a big part of the common materialist presumption that physics has “complete causal closure.” When physical phenomena are based on quantum phenomena, which have a built-in random factor, it’s hard to see how that can be characterized as “complete causal closure.” Granted, there are the intermittent attempts of a few determined determinists — such as David Bohm, to rewrite quantum theory into something that it’s not; but among physicists the Copenhagen interpretation wins broad support. One might claim that the “complete causal closure” of physics does not imply that all events have a physical cause, but it only implies that if they have any cause at all, then that cause must be physical. However, physicists generally don’t make those same kinds of claims on reality; they’re inherently more modest than philosophers when it comes to the role of physics in describing the nature of the universe.

    The standard assertion of “No Hidden Variables” refers to no hidden *physical* causative factors, which would lead to physical determinism. It says nothing at all about potential non-physical variables that might act as causative factors. To some minds, the gap in causation at the quantum level — which is ubiquitous, since all physical processes are ultimately based on quantum physics — is one possible place for consciousness to hide out in the physical world, and for free will as a causative agent. (This could readily lead to a panpsychist view of the physical world, since consciousness per se would not be restricted to biological entities and processes, but would permeate all of physical reality. However, the specifics of biology and physics and chemistry would of course restrict the range of actions and behaviors that any physical entity could exhibit, as well as their range of phenomenal experience.)

    This introduction of non-physical aspects to the universe is widely abhorred by contemporary philosophers, who often seem to think they are being “scientific” by adopting the philosophical stance of materialism. But materialism is not demonstrated by science; it’s just a metaphysical assumption. It so happens that physical science generally works well with materialism as a useful default assumption; but that’s only to say that physical science is about physical stuff, and not about non-physical stuff. All areas of inquiry have a proper domain, and the fact that the proper domain of physical science is physical stuff should not imply that there are no other domains or dimensions to reality, or that other areas of inquiry should be compelled to limit themselves to the default assumptions of physical science.

    And, of course, the physical sciences can also be compatible with other metaphysical stances, such as idealism or dualism. There is no necessary violation of the known facts or laws of science involved in assuming that all the scientific facts that we know about the universe are the result of a universe composed of consciousness. Insofar as physics does not concern itself with consciousness, it has nothing to say about whether consciousness is constructed out of physical processes, or whether the physical universe is constructed out of consciousness, or whether consciousness and physicality are two aspects of some underlying unity.

    But when it comes to attempts to understand the mind, regarding the materialistic assumption as the necessary default assumption makes no sense. It’s like wearing dark purple sunglasses, and then looking at a forest and declaring that no non-purple things exist. The most interesting things may be unintentionally filtered out that way.

    Re comment #7, it did not appear that comment #6 was asserting that quantum phenomena can explain consciousness or its phenomenal content. I took Mr. Seyfried as making a more general point: that materialism assumes a physical cause for all physical events; and that that assumption has been amply disproven by quantum mechanics. But I think one could hold the materialist assumption without the assertion of physical determinism that violates quantum mechanics. That would mean accepting that many physical events ultimately have no cause at all, neither a physical cause nor a non-physical cause.

    As to explaining consciousness itself, that is a much harder problem than merely explaining some of the details of the contents of conscious experience. David Chalmers did a great job of addressing “the hard problem of consciousness” in his book, outlining how there is something there that seems, from our own direct subjective experience of consciousness, to be fundamentally non-physical. He ended up defending a dualistic metaphysics of sorts; but most of the same arguments would work equally well for an idealistic metaphysics.

    Idealistic metaphysics is very common in eastern philosophy, but apparently it’s anathema in western philosophy these days. (And Berkeley’s version of idealism was problematic; but vedantic or Buddhist idealism is quite a different beast.) However, the only objection that western philosophers can seem to raise against idealism is the “but that’s just absurd!” objection. That seems like a woeful lapse of intellectual rigor on their part. To maintain that the position of idealism is simply untenable by anyone who is intelllectually serious is demonstrably wrong; as evidenced by its popularity among the most rigorous of Indian philosophers and physicists alike. A reductio ad absurdum argument loses its teeth when confronted with the existence of many profound thinkers who don’t seem to find the “absurdity” to be absurd at all.

    The study of consciousness as an interdisciplinary effort involving science and philosophy and psychology has been revealing fascinating things about the mind and how we think of it. But with regard to some of the “hard problems” of consciousness, I can’t help but feel that this area of inquiry will be chasing its own tail in some ways, so long as researchers feel duty bound to swear oaths of fealty to the presumption of a materialistic metaphysics.


    Re comment# 7, in attempting to explain consciousness, there is not just
    one hard problem, there are two hard problems. The first problem is to explain the sheer existence of consciousness per se; the second problem is to explain the phenomenal content of consciousness. Attempting to explain the existence of consciousness is similar to the problem of explaining the existence of the electromagnetic forces or space-time. Attempting to
    explain the phenomenal content of consciousness amounts to the problem of explaining the design of the most complex biophysical information-processing system known (the human brain). Explaining the sheer existence of consciousness seems currently to be as intractable in the study of mind as explaining the existence of the electromagnetic forces is in physics.
    On the other hand, we are making real progress in elucidating the neuronal mechanisms and systems in the brain that can account for the phenomenal content of consciousness.

    Arnold Trehub


    Nice synopsis and commentary… and as a physician with an interest in the neurosciences, I would argue that anyone challenging Sir Francis Crick’s “astonishing hypothesis” that the mind consists of anything beyond our intricately evolved neural network (aka physical brain) is engaging in magical thinking at the very least.

    I would add that along with researching dream-states during sleep… progressive levels of anesthesia and brain/mind altering drugs are fertile ground which have been sadly abandoned until only recently.

    Regarding one commenter pontificating that QM has slayed any notion of a deterministic universe… and without a shread of evidence asserts free-will (FW) exists… I think absurd. Like evolution, the great weight of evidence has demonstrated the utter lack of FW, whether from mountains of reasearch in neurobiology or interrelated genetics. The alleged randomness of QM does not equate in any sense with some notion of FW. Quite the contrary, it would be a strong argument against it. Someone as eminent as Gerard t’Hooft has authored a paper on the “determinism underlying QM” as I recall!
    I challenge anyone who desires to escape the determined Natural world (but certainly NOT the simplistically “mechanistic”) to explain the nature of this “free-willing agent” which somehow, by some means, supervenes on our physical brains. When did this supernatural agency appear in the context of human evolution, apart from the evolution of our physical brains? When during our embryological development does FW appear? Does FW operate at the synaptic, neuronal level… or is it some kind of ethereal super-identity, which comes from who-knows-where… for who-knows-why?


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