You write that you come to this idea as a way of solving a problem in the way consciousness is studied. What, in your mind, is the problem? There is a deep mystery in understanding how what we know about ourselves from the inside fits together with what science tells us about matter from the outside. But in my new book, I argue that the problem of consciousness results from the way we designed science at the start of the scientific revolution.
Think about the redness of a red experiences or the smell of flowers or the taste of mint. This is really important, because although the problem of consciousness is taken seriously, most people assume our conventional scientific approach is capable of solving it. And they think this because they look at the great success of physical science in explaining more and more of our universe and conclude that this ought to give us confidence that physical science alone will one day explain consciousness.
However, I believe that this reaction is rooted in a misunderstanding of the history of science. Yes, physical science has been incredibly successful. I designed physical science to deal with quantities, not qualities.
That sounds like a bizarre claim at first; you read a physics textbook, you seem to learn all kinds of incredible things about the nature of space, time and matter. But what philosophers of science have realized is that physical science, for all its richness, is confined to telling us about the behavior of matter, what it does.
Physics tells us, for example, that matter has mass and charge. These properties are completely defined in terms of behavior, things like attraction, repulsion, resistance to acceleration.
Physics tells us absolutely nothing about what philosophers like to call the intrinsic nature of matter: what matter is, in and of itself. So it turns out that there is a huge hole in our scientific story. The proposal of the panpsychist is to put consciousness in that hole. Consciousness, for the panpsychist, is the intrinsic nature of matter. But matter can be described from two perspectives. What this offers us is a beautifully simple, elegant way of integrating consciousness into our scientific worldview, of marrying what we know about ourselves from the inside and what science tells us about matter from the outside.
What are the objections to this idea that you hear most frequently? And how do you respond? At the end of the day, you should judge a view not by its cultural associations but by its explanatory power.
This suggests that the presence of consciousness in a wakeful person depends on a certain level of functional integration supported by cortical feedback loops Edelman, ; Alkire et al. A major contribution of cybernetic theory was to recognize the importance of feedback mechanisms for controlling behavior in mechanical and living systems Wiener, ; Bateson, Feedback systems are self-referential; one part of the system casually affects another, which in turn affects the first.
Such systems are apt to generate behaviors that are an irreducible property of the system as a whole Hofstadter, ; Deacon, One example is video feedback, which occurs when a video camera is pointed at a monitor showing the output from the camera Crutchfield, Since this is an energetically actuated process we can infer, following the arguments already given, that there is something it is like to be the video feedback system in full bloom, from its intrinsic perspective.
But it is not conscious. Stills from a video feedback sequence generated by the author. Pepperell The human brain undergoes recursive or reentrant behavior of an unimaginably higher order of complexity than in the video system But the underlying operating principle may be analogous. Video feedback arises because the system is organized as a self-observing loop. If we assume that reentrant activity in the brain is also a kind of self-observing loop in which processes in one part the brain both affect and are affected by processes in other parts, then we can envisage a kind of pattern blooming in the brain analogous to that we see in video feedback.
This pattern would be actuated by sufficiently organized electro-chemical activity, among neurons and neurotransmitters, channeled through reentrant neural circuits. The something it is like-ness a brain organized in this way would be undergoing is of a different order to that of a brain with diminished integration in dreamless sleep or under anesthesia. In other words, there is something it is like, intrinsically, to be something it is like, recursively, to undergo the particular organization of actualized differences found in the conscious brain.
Is it reasonable then to propose that consciousness is caused by the way energetic activity is dynamically and recursively organized in the brain? It is no less reasonable than attributing the causes of other biological phenomena, such as the behavior of the nematode worm, to the way energetic activity is organized.
If consciousness is a physical biological and chemical process, and if physical processes are caused by energetic activity alongside forces and work , then consciousness, in principle, could be caused by energetic activity and the way it is organized. In —8, Charles Sherrington gave a series of lectures on the relationship between energy and mind, collected in the volume Man on his Nature Sherrington, In line with the physics of his day, Sherrington understood the natural world to be composed of forms of energy.
If we are to naturalize consciousness, then we must reconcile energy and the mind. I have outlined a principle that may help to explain consciousness as a physical process.
Accordingly, we arrive at a view of physical processes in nature as actualized differences of motion and tension. If consciousness is a natural physical process then it should be explicable in terms of energy, forces and work. Energy is a physical property of nature that is causally efficacious and, like forces and work, can be conceived as actualized differences of motion and tension.
Evidence from neurobiology indicates that the brain operates on the principle of energetic processing and that a certain organization of energy in the brain, measured with information theoretic techniques, can be reliably predict the presence and level of consciousness. Since energy is causally efficacious in physical systems, it is reasonable to claim that consciousness is in principle caused by energetic activity and how it is dynamically organized in the brain.
Information in the biological context is best understood as a measure of the way energetic activity is organized, that is, its complexity or degree of differentiation and integration. Information theoretic techniques provide powerful tools for measuring, modeling, and mapping the organization of energetic processes, but we should not confuse the map with the territory. Actualized differences, as distinct from abstract differences represented in mathematics and information theory, are characterized by there being something it is like, intrinsically, to undergo those differences, that is, to undergo antagonistic states of opposing forces.
All actualized differences undergo this something it is like-ness, but not all contribute to consciousness. It is proposed that a particular kind of activity occurs in human brains that causes our conscious experience. It is a certain dynamic organization of energetic processes having a high degree of differentiation and integration.
This organization is recursively self-referential and results in a pattern of energetic activity that blossoms to a degree of complexity sufficient for consciousness. If consciousness is a physical process, and physical processes are driven by actualized differences of motion and tension, then there is something it is like to undergo actualized differences organized in a certain way in the brain, and this is what we experience — intrinsically The author confirms being the sole contributor of this work and has approved it for publication.
The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Abbott, M. Google Scholar. Aboy, M. IEEE Trans. Alkire, M. Consciousness and Anesthesia, Science , — Allen, J. London: Harvard University Press. Annila, A. On the character of consciousness. Aristotle Thomas Taylor.
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Hameroff, S. Life Rev. Hawking, S. A Brief History of Time. London: Bantam Books. Heisenberg, W. Hine, R. So it appears that the sights, sounds and other sensations of life as we experience it are generated by regions within the posterior cortex. As far as we can tell, almost all conscious experiences have their origin there. What is the crucial difference between these posterior regions and much of the prefrontal cortex, which does not directly contribute to subjective content?
The truth is that we do not know. Even so—and excitingly—a recent finding indicates that neuroscientists may be getting closer. An unmet clinical need exists for a device that reliably detects the presence or absence of consciousness in impaired or incapacitated individuals. During surgery, for example, patients are anesthetized to keep them immobile and their blood pressure stable and to eliminate pain and traumatic memories.
Unfortunately, this goal is not always met: every year hundreds of patients have some awareness under anesthesia. Another category of patients, who have severe brain injury because of accidents, infections or extreme intoxication, may live for years without being able to speak or respond to verbal requests. Establishing that they experience life is a grave challenge to the clinical arts.
His damaged radio does not relay his voice, and he appears lost to the world. This is the forlorn situation of patients whose damaged brain will not let them communicate to the world—an extreme form of solitary confinement. In the early s Giulio Tononi of the University of Wisconsin—Madison and Marcello Massimini, now at the University of Milan in Italy, pioneered a technique, called zap and zip, to probe whether someone is conscious or not. A network of electroencephalogram EEG sensors, positioned outside the skull, recorded these electrical signals.
As they unfolded over time, these traces, each corresponding to a specific location in the brain below the skull, yielded a movie. These unfolding records neither sketched a stereotypical pattern, nor were they completely random. Remarkably, the more predictable these waxing and waning rhythms were, the more likely the brain was unconscious. Massimini and Tononi tested this zap-and-zip measure on 48 patients who were brain-injured but responsive and awake, finding that in every case, the method confirmed the behavioral evidence for consciousness.
The team then applied zap and zip to 81 patients who were minimally conscious or in a vegetative state. For the former group, which showed some signs of nonreflexive behavior, the method correctly found 36 out of 38 patients to be conscious.
It misdiagnosed two patients as unconscious. Of the 43 vegetative-state patients in which all bedside attempts to establish communication failed, 34 were labeled as unconscious, but nine were not.
Their brains responded similarly to those of conscious controls—implying that they were conscious yet unable to communicate with their loved ones. Ongoing studies seek to standardize and improve zap and zip for neurological patients and to extend it to psychiatric and pediatric patients. Sooner or later scientists will discover the specific set of neural mechanisms that give rise to any one experience.
Although these findings will have important clinical implications and may give succor to families and friends, they will not answer some fundamental questions: Why these neurons and not those?
Why this particular frequency and not that? Indeed, the abiding mystery is how and why any highly organized piece of active matter gives rise to conscious sensation. After all, the brain is like any other organ, subject to the same physical laws as the heart or the liver. What makes it different? What is it about the biophysics of a chunk of highly excitable brain matter that turns gray goo into the glorious surround sound and Technicolor that is the fabric of everyday experience?
Ultimately what we need is a satisfying scientific theory of consciousness that predicts under which conditions any particular physical system—whether it is a complex circuit of neurons or silicon transistors—has experiences. Furthermore, why does the quality of these experiences differ?
Why does a clear blue sky feel so different from the screech of a badly tuned violin? Do these differences in sensation have a function, and if so, what is it? Such a theory will allow us to infer which systems will experience anything. Absent a theory with testable predictions, any speculation about machine consciousness is based solely on our intuition, which the history of science has shown is not a reliable guide.
Fierce debates have arisen around the two most popular theories of consciousness. The theory begins with the observation that when you are conscious of something, many different parts of your brain have access to that information.
If, on the other hand, you act unconsciously, that information is localized to the specific sensory motor system involved. For example, when you type fast, you do so automatically. Asked how you do it, you would not know: you have little conscious access to that information, which also happens to be localized to the brain circuits linking your eyes to rapid finger movements. GNW argues that consciousness arises from a particular type of information processing—familiar from the early days of artificial intelligence, when specialized programs would access a small, shared repository of information.
According to GNW, consciousness emerges when incoming sensory information, inscribed onto such a blackboard, is broadcast globally to multiple cognitive systems—which process these data to speak, store or call up a memory or execute an action. Because the blackboard has limited space, we can only be aware of a little information at any given instant. The network of neurons that broadcast these messages is hypothesized to be located in the frontal and parietal lobes.
Once these sparse data are broadcast on this network and are globally available, the information becomes conscious. That is, the subject becomes aware of it. Whereas current machines do not yet rise to this level of cognitive sophistication, this is only a question of time.
GNW posits that computers of the future will be conscious. Integrated information theory IIT , developed by Tononi and his collaborators, including me, has a very different starting point: experience itself.
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