Piero Scaruffi(Copyright © 2013 Piero Scaruffi | Legal restrictions )
These are excerpts and elaborations from my book "The Nature of Consciousness"
Paradoxes and weird properties of consciousness abound.
Why can't i be aware of my entire being? We only have partial introspection. We have no idea what so many organs are doing in our body.
Consciousness is limited to my head. Do I need hands and feet in order to be conscious? Is consciousness only determined by what is in the head, or is it affected also by every part of the body? Am I still the same person if they cut my legs? What if they transplant my heart?
We can only be conscious of one thing at a time. There are many things that we are not conscious of. How do we select which thing we want to be conscious of?
Why can I only feel my own consciousness and not other people's consciousness? Why can't I feel other people's feelings? Why can't anybody else feel my feelings? Conscious states are fundamentally different from anything else in nature because they are "subjective" and “opaque” (i can’t feel yours). They are not equally accessible to all observers.
Consciousness is a whole, unlike the body which is made of parts, unlike everything else which can be decomposed into more and more elementary units. Conscious states cannot be reduced to constituent parts.
How did consciousness come to exist in the first place? Did it evolve from non-conscious properties? In that case, why? What purpose does it serve?
Could I be conscious of things that I am not conscious of? Am I in control of my consciousness? Is this conscious thought of mine only one of the many possible conscious thoughts that I could have now, or is it the only conscious thought that I could possibly have now? Is consciousness in control of me? This question is crucial to understanding whether there is a locus of consciousness in the brain, or whether consciousness is simply a side-effect of processes that occur in the brain.
The most frustrating property of consciousness is probably its opacity: we cannot know who and what is conscious. How widespread is consciousness? Who else is conscious besides me? Are other people conscious the same way i am? Are some people more conscious and others less conscious? Are some animals also conscious? Are all animals conscious? Are plants conscious? Can non-living matter also be conscious? Is everything conscious?
Can things inside conscious things be conscious? Are planets and galaxies conscious? Are arms and legs conscious?
What is the self? The self seems to represent a sense of unity, of spatial and temporal unity: "my" self groups all the feelings related to my body, and it also groups all those feelings that occurred in the past. My body changed over the years, and my brain too. All the cells of the body change within seven years. Therefore my “mind” must have changed too. But the self somehow bestows unity on that continuously changing entity. If we consider that our bodies are ultimately made of elementary particles, and that the average lifetime of most elementary particles is a fraction of a second, we can say that our bodies are continuously rebuilt every second. The matter of our bodies changes all the time. The only thing that is preserved is the pattern of matter. And even that pattern changes slowly as we age. Not even the pattern is preserved accurately. What makes us think that we are still the same person? How can I still be myself?
Laws that protect animals are not clear about "what" makes an animal worthy of protecting: killing a neighborhood cat because I don't like it is generally considered offensive, but killing a spider because I don't like it is absolutely normal. One can own a dog and file a suit against somebody who killed it, but one cannot own an ant and file a suit against somebody who stepped over it. Why slaughtering cows by the millions is a lawful practice and killing a pigeon in a square is a crime?
The US physicist Erich Harth focused on the following properties of consciousness: "selectivity” (only a few neural processes are conscious); "exclusivity" (only one perception at the time can be conscious); "chaining" (one conscious thought leads to another one"); "unitarity" (the sense of self).
These properties of consciousness (partiality, sequentiality, irreducibility, unity, opacity, etc) set consciousness apart from any other natural phenomenon. And make it difficult, if not impossible, to study it with the traditional tools of the physical sciences.
Two Levels of Consciousness
We can take consciousness as a primitive concept (just like "time", "space" and "matter"), that we all “know” even though we cannot define it. We can define what the brain (or at least the neural system) is and what brain processes are. We can define cognition, as the set of cognitive faculties (learning, memory, language, etc), each of way is relatively easy to define.
When we refer to cognition, we are often interested in more than just the neural process underlying a cognitive faculty. We are interested in general questions such as "how can a living thing remember something" and "how can a living thing learn something". Such questions have two parts. The first part is about the mechanism that allows a piece of living matter to remember or learn something in the sense of being able to perform future actions based on it. The second part is about the awareness of remembering or learning something. The first part doesn't really require consciousness, and it may well be explained on a purely material basis. Even non-conscious things (non-living matter) may be able to remember and learn. Ultimately, the first part of the cognitive process can be summarized as: "Matter modifies itself based on occurrences in the environment so that its future behavior will be different". Fascinating and intriguing, but far less mysterious than the other half of the phenomenon: "... and, in the process, it is also aware of all of this".
The mechanisms that preside over memory, learning, language and reasoning can be described in material terms. And machines have been built that mimic those processes. The other half of the problem is still as mysterious as it was centuries ago. How does a brain process give rise to the awareness that the process is going on?
It looks like by "mind" we always meant something physical, material, reducible to physical processes inside the brain, which could be reproduced in a laboratory, and possibly on beings made of a different substance. But at the same time we also meant something that today's sciences cannot replicate in a laboratory: the awareness of that physical process going on inside us.
“Mind” encompasses both the cognitive processes (of memory and learning, language and reasoning) and the “feeling” associated with those processes: consciousness.
At closer inspection, "consciousness" is a term that encompasses a number of phenomena: thought, the self (the sense of the “i”, the awareness of being), bodily sensations (such as pain and the color red), emotions (anger, happiness, fear, love). But not necessarily cognition (reasoning, memory, learning, etc).
There is a "narrative", "cognitive", "higher-level" consciousness, which is relatively detached from our bodily experience and which seems to rely on language, and there is an "experiential", "sensorial" consciousness, which has to do with sensations received from the senses, i.e. with our immediate bodily experience. The latter may be common to many species, while the former might be an exclusive of humans because it may require some additional level of circuitry in the brain than basic sensations or emotions.
The former is what we call "thought", including the self. The latter consist of "sensations" and “emotions”.
Consciousness is the awareness of existing. Self is the awareness of lasting in space and time (of being an “i”). Sensations are bodily feelings such as pain, the color red, warmth. Emotions are non-bodily feelings such as anger, happiness, fear. Cognition encompasses the processes of reasoning, memory, learning, speaking, etc. Perception is the physical process of perceiving the world. Thought is the act of being conscious over an extended period of time.
The problem of phenomenal qualities has puzzled philosophers for centuries. There is no “red” around me, just particles. Where does the “red” that I see come from? That red exists in my mind, but it does not exist outside my mind. Red is in me, not in the world.
How can a reality made of atoms of finite size be generating my feeling of something as uniform and continuous as the color red?
In 1929 the US philosopher Clarence Lewis called them “qualia” (from the Latin “quale”, which is the dual of “quantum” and refers to the subjective aspect of a thing). Qualia are qualities that are subjective, directly perceived and known in an absolute way. The taste of something, the color of something, a pain or a desire are associated to qualia, to “feelings” of those things.
Qualia are subjective: I cannot be sure that another person’s “red” is identical to my red.
Qualia are known in an absolute way: in another world red could correspond to a different frequency of light, and we would have to change the branch of Physics that deals with colors, but what I see as “red” I would still see as red.
Why does Nature present itself to my senses in two contradictory ways? If I believe my immediate perceptions, there is red. If I try to make sense of my perceptions, I work out a theory of Nature according to which there is no red, but only a vast mass of floating particles.
As a matter of fact, matter is “inscrutable” to our consciousness. We would like to think that, if nothing else, we know what the world is. We may be puzzled by the nature of mind, but we do know what matter is. At closer inspection, even matter turns out to be a bit of a mystery. We cannot perceive, and therefore conceive, what matter ultimately is. Our mind presents us with a game of illusions, whereby the world is populated with objects, and objects have shapes and colors. Science, on the other hand, tells us that there are only particles and waves. We cannot perceive that ultimate reality of matter. Matter is inscrutable to us.
We know what consciousness is because we feel it. We know what matter is because we sense it. Because we can sense it, we can build scientific theories on the nature of matter. But we cannot feel it, we cannot feel what matter ultimately is. Because we can only feel it, we cannot build scientific theories on the nature of consciousness. Although we can feel it.
Feelings Are Not in the Head
The US philosopher Michael Tye believes that our feelings are not in the head at all. Neurologists can never explain what it is like to smell or taste.
The starting point is a thought experiment by the Australian philosopher Frank Jackson ("Epiphenomenal Qualia", 1982). Imagine a scientist who knows everything about a subject, but has not experienced that subject. She has lived her entire life in a black and white environment but studied all there is to know about colors. She has seen colored objects only on a black and white television set. She just has not seen them in color. But she knows what color is and what properties it obeys and so forth. Then one day she steps outside her black and white environment and experiences the colors of those objects. No matter how much she knew about colors, when she actually sees a red object, she will experience something that she had not experienced before, she will "learn" something that she did not know: the "what it is like" of seeing a color (what Tye calls the "phenomenal character" of seeing a color). There is a difference between objective knowledge of something and subjective experience of something. The latter constitutes the “phenomenal consciousness” of something.
Tye believes that phenomenal states cannot be possibly realized only by neural states (as opposed to what physicalism claims). Tye believes that mental states are symbolic representations, but he differs from Fodor in that he does not believe that the representation for a sensation involves a sentence in the language of thought. The belief of something is represented by a symbolic structure which is a sentence. The sensation of something, instead, is represented by a symbolic structure which is not a sentence. The format (the symbolic structure) of a sensory representation is instead map-like: a pattern of activation occurring in a three-dimensional array of cells each containing a symbol and to which descriptive labels are attached. The patterns are analyzed by computational routines that are capable of extracting information and then attaching the appropriate descriptive labels.
A sentence would not be enough to represent a sensation, as a sensation includes some kind of "mapping" of the domain it refers to. For example, pain is about the body, and needs a way to represent the body parts that are affected by pain. Sentences lack this map-like representational power. Tye's patterns of activation in those map-like structures are therefore representations of bodily changes that trigger some computational processing. And this is what an emotion is, according to Tye.
Tye's hypothesis is that phenomenal consciousness is not in the neurons: phenomenal consciousness is in the "representations".
Tye believes that the body is equipped (as a product of evolution) with a set of specialized sensory modules for bodily sensations (for pain, hunger, and so forth) just like the specialized sensory modules for the five senses (physically different neural regions). Each module is capable of some computation on some symbolic structure.
Additionally, Tye notes that the object of a feeling is non-conceptual. We have different feelings for different shades of red even if we don't have different concepts for those shades of red. Thus we are capable of many more feelings than concepts.
Tye concludes that "phenomenal states lie at the interface of the non-conceptual and conceptual domains", at the border between the sensory modules and the cognitive system.
Tye analyzes the “phenomenal character” ("what it is like") of an experience and its “phenomenal content” ("what is being experienced"). Tye shows that the phenomenal character of an experience is identical to its phenomenal content: the feeling of pain in a foot cannot be abstracted and remains the fact that it is pain in that foot. Tye, therefore, concludes that phenomenal aspects are a subset of the representational aspects, and not distinct from them.
Because phenomenal character (the "what it is like" feeling) is phenomenal content, experiencing "what it is like" depends on having the appropriate system of concepts: one must have the appropriate system of concepts in order to understand what it is like to experience something. I cannot know what it feels like to be a bat because I don't have the appropriate concepts to feel what a bat feels.
Appropriate concepts are "predicative" and "indexical", which can be acquired only from direct experience (past or present, respectively).
Tye does not truly solve the "explanatory gap" between phenomenal states and physical states (how subjective feelings arises from neural states that are not subjective). His theory offers an explanation for why we cannot know "what it feels like" to be a bat, but does not explain why the bat feels whatever it feels, i.e. how feelings are created from brain states.
An Impossible Science?
It was the US psychologist Karl Lashley who first warned that… the mind is never conscious. The mind can never perceive the processing that goes on in the brain when the mind is thinking something. When I think about myself, I am not conscious of what my brain is doing. Whatever it is that I am feeling, it is not what the brain is doing. I am not aware of the billions of electrochemical processes switching neurons on and off.
One can even suspect that it is simply impossible for a conscious being to understand what consciousness is. The US philosopher Thomas Nagel pointed out that one is only capable of conceiving things as they appear to her, but never as they are in themselves. We can only experience how it feels to be ourselves. We can never experience how it feels to be something else, for the simple reason that we are not something else. As Nagel wrote (“What is it like to be a bat”, 1974), we can learn all about the brain mechanisms of a bat's sonar system but we will never have the slightest idea of what it is like to have the sonar experiences of a bat. Likewise, understanding how the human brain works may not be enough to understand human consciousness.
The Australian philosopher Frank Jackson ("Epiphenomenal Qualia", 1982) used the example of a color-blind neuroscientist who can only see black and white and, no matter how much she knows about the neurophysiology of colors, will never experience what red feels like.
The British philosopher Colin McGinn argued that consciousness cannot be understood by beings with minds like ours. McGinn believes that there is nothing "magic" about consciousness: consciousness is a natural phenomenon just like many others (lightning or hurricanes or comets) and, as such, it is a consequence of the way matter is structured and functions (specifically, how the brain works).
We are capable of understanding natural phenomena like lightning and hurricanes, but McGinn suspects that we are not capable of understanding "all" natural phenomena. There are natural phenomena that our mind cannot comprehend, just because our mind is not an infinitely powerful computer.
In a sense, McGinn’s central thesis is that our mind has limitations. Consciousness itself might be one of the phenomena that fall within the mind's limitations, i.e. fall outside the "cognitive closure" of the human mind. That does not mean that nobody can ever explain consciousness: a being equipped with a "better" mind could understand how consciousness works, where it comes from and what it is. But not our mind.
We can understand how the brain works. The brain is a natural phenomenon that we can easily investigate with our science. We will learn more and more about the brain. We will eventually work out a very detailed model of the brain. We may even be able to reproduce the brain molecule by molecule. But we will never be able to figure out how emotions arise from the unconscious matter that makes up the brain.
McGinn’s fundamental assumption is that the human mind is biased in its cognitive skills. This follows from a Darwinian view of life: all of our organs are biased, one way or another, towards coping with the environment. McGinn simply extends this principle to the mind. Our mind is very skilled at understanding spatial and temporal relationships, and at doing what we call Science. Our mind is probably not very skilled at doing things that would be useful on Mars but that do not exist on Earth. Thus it is reasonable to assume that the human mind has been designed by evolution to solve some problems better than others, and not to solve many other problems at all.
In particular, McGinn thinks that our intelligence is not designed to understand consciousness. Science is the systematic understanding of nature by the human mind, but it is limited to what the human mind can understand. There might be many things in nature that the human mind will never understand, and maybe not even perceive. Consciousness is one of them. Our brains were not biologically designed to understand consciousness. McGinn even speculates that knowledge of ourselves is useful to a limit: maybe if we could fully understand ourselves, we would get very depressed and not willing to survive anymore. Thus natural selection may have pruned away the ones who did understand consciousness, and left only the ones who could not understand it, of whom we are the descendants.
Inspired partly by the British philosopher Bertrand Russell and partly by the German philosopher Immanuel Kant, McGinn argues that consciousness is known by the faculty of introspection, as opposed to the physical world, which is known by the faculty of perception. The relationship between one and the other, which is the relationship between consciousness and brain, is "noumenal", or impossible to understand: it is provided by a lower level of consciousness that is not accessible to introspection. That is why consciousness does not belong to the "cognitive closure" of the human organism.
Understanding our consciousness is beyond our cognitive capacities, just like a child cannot grasp social concepts or i cannot relate to a farmer's fear of tornadoes. McGinn points out that other creatures in nature lack the capacity to understand things that we understand (for example, the general theory of relativity). There are parts of nature that they cannot understand. We are also creatures of nature, and there is no reason to exclude that we also lack the capacity to understand something of nature. We may not have the power to understand everything, unlike what we often assume. Some explanations (such as where the universe comes from, and what will happen afterwards, and what is time and so forth) may just be beyond our mind's capacity. Explanations for these phenomena may just be "cognitively closed" to us. Phenomenal consciousness may be one such phenomenon.
"Mind may just not be big enough to understand mind".
McGinn speculates that consciousness might be a very ancient invention. Indeed, the fact that consciousness has no spatial dimensions leads him to speculate that consciousness may have tapped into a non-spatial property that disappeared with the Big Bang (the cosmic event that created the spatial universe we live in). Our minds may be remnants of a dimension that does not exist anymore but that was pervasive in the pre-Big Bang universe.
He cunningly refutes the idea that computers can be conscious in virtue of being computers. McGinn explains that this idea is based on a bad theory of consciousness. We have no evidence that the property of running a program is the property that yields consciousness. This does not mean that conscious machines are impossible: the key is in finding out what is the property that yields consciousness, and then implementing that feature in a machine. McGinn points out that one such machine already exists: me. Thus it is feasible. Cogito, ergo I am feasible. McGinn changes the question to make it more interesting: can a machine made of inorganic material be conscious?
Implicitly, McGinn assumes that our “cognitive closure” does not change with time, that it is a constant of the human condition. On the other hand, it is obvious that it changes during the course of a lifetime: children cannot grasp concepts that adults can. One can also argue that our “cognitive closure” has evolved over the centuries, that we are more “conscious” today than we were thousands of years ago. Certainly, concepts such as democracy and women’s rights are more obvious to today’s humans than they were to even the most enlightened of the ancient Greek philosophers. Studies on ancient texts point to a reliance on gods that today has been replaced by a reliance on our own opinions. One can argue that today we “think” differently. One can argue that each generation uses knowledge from the previous generation to expand that “cognitive closure”.
The question then is whether the “cognitive closure” that McGinn talks about is a temporary limitation, a “stage” in the evolution of manking, or a permanent deficiency of our mind (due, say, to the structure of the brain, or to some impossible neural connections, or to the limited capacity of our memory). Since McGinn does not “quantify” where the cognitive closure comes from, i.e. what it is physically, one cannot decide whether it can be overcome or not by future generations. If we do not know what causes that cognitive closure, we cannot know whether it can be overcome.
The Kenyan-born biologist Richard Dawkins, following the British biologist John Haldane, believes that, just like there are limits to what human eyes can see because they only see what made sense to evolve over millions of years, there is no reason to believe that evolution shaped the human brain to perform any more function than what is needed to survive in its environment. For example, we can only see in black and white mode at night, and we don’t see (nor hear) the extreme parts of the spectrum of frequencies. If that is true for the eyes, it is likely to be true also for the brain: the human brain evolved the ability to “think” what matters for the survival of humans, but not the ability to “think” other thoughts, which are therefore beyond the ability of the human brain. Just like we cannot run as fast as a cheetah, we cannot think as profoundly as some other being that (who?) has evolved or will evolve a better kind of brain.
Nonetheless, one can object: if our brains were not designed to understand consciousness, why are we wondering about it? Were our brains designed to wonder about consciousness? Were our brains designed to wonder about something that we cannot possibly understand? Why?
And so the Israeli physicist David Deutsch counters that we used to live in a world of supernatural entities. Then we discovered that we are capable of explaining how the world works because the world obeys mathematical laws that our brain can master. Therefore we became universal beings, capable of understanding anything that happens in the universe ruled by those laws of nature. A higher intelligence (incomprehensible to us) can only exist if the universe is not explicable, i.e. if there exist supernatural beings. In other words, the cognitive closure of human brains would imply that the ancient superstitions were correct.
It is the scientific "explanation" that allows us to create a long chain of interpretation that allows us to understand phenomena that are very far from our everyday experience. For example, astronomical observation consists of, in practice, just looking into devices built out of humble materials found here on Earth but, ultimately, allows the mind to visit distant worlds. The mind can "leave" the body for this spectacular voyage because of the "explanations" that guarantee it is not just being tricked by drugs. There is something special about this process that makes humans truly unique.
Deutsch disagrees with those who think that there is nothing special with this typical planet of a typical star of a typical galaxy (the principle of mediocrity): humans have created conditions (for example, low-temperature refrigerators) that are very rare in the universe. Deutsch emphasizes that most of the universe is very different from the environment that humans created in their cities, homes and especially laboratories. What made humans unique is that they can use technology to expand the capabilities of their brains. Whatever caused their brains to evolve the way they did, those brains are now capable of going beyond their original survival functions. And the reason that technology does that is the explanatory knowledge that only humans have learned to master. What is unique about explanatory knowledge is obvious if one considers that humans managed to survive in an extremely hostile biosphere and even moved to environments that are not the ones in which they were shaped by natural selection. Other species have knowledge too, but the kind of straightforward knowledge that limits their reach to their habitat. The explanatory knowledge of humans allows them to do things that their brains were not programmed for and their bodies could not do without help from technology.
Thus Deutsch calls humans "universal constructors": humans can transform anything into anything as long as they understand the natural laws that govern the universe and then build technology according to those laws. If the universe is governed by deterministic rules, then the human brain can eventually (explanation after explanation) get to understand everything. We are capable of everything, and in particular of understanding everything. There is nothing that obeys the laws of nature that we cannot understand. If such a thing existed, it would have to be "supernatural" by definition: not obeying the laws of nature. In a universe governed by mathematical laws, the reach of explanatory knowledge is infinite, and therefore so is the reach of a brain that is capable of acquiring explanatory knowledge recursively (one explanation leading to another one). There is no limit to human knowledge. There is no limit to human creation.
Historically, it wasn't always this way. At some point humans became what their brain made possible: universal constructors. He links this conceptual revolution with the Enlightenment, that spawned rebellion against authority in many fields, including science: those rebels looked for explanations, not just dogmas. Furthermore, the Enlightenment introduced the notion that progress is good and should be a universal ideal to achieve by society. So the chain of explanations that leads to more and more knowledge became not only possible but an explicit goal of humankind.
The effect of brains like ours (brains that can deal with explanatory knowledge and therefore become universal constructors who can alter their environment at will) is significant. Deutsch points out that astrophysics is incomplete without a theory of people because people can alter the course of events that the laws of nature alone would cause. If we don't consider the actions of people, we can't understand why the Earth is the way it is.
Furthermore, the effect of a knowledge-processing brain is profound also because an intelligent deliberate transformation is actually more likely to happen than a spontaneous one: the chances that an object is changed by a spontaneous transformation (one caused only by the laws of nature) are relatively low in the grand scheme of things, whereas the chances that an object is changed by an intelligent being for whatever purpose are very high.
In other words: the universality of the laws of nature coupled with a universal constructor like the human mind yields unlimited knowledge growth.
Deutsch argues that the well-known limitations on mathematics and computations (Godel's Theorem and the likes) do not affect his claims that humans can extend knowledge indefinitely: one can understand a mathematical statement without proving it. Basically, the proof is a technicality. If you can't prove it, it doesn't mean you don't "know" something. The only limit to human knowledge that Deutsch sees is the impossibility to predict future knowledge: the fact that we can find solutions to any problem does not mean that we already know those solutions.
The physics of knowledge representation is that the physical system of the brain somehow contains a model of the physical system of the entire universe. As more and more knowledge is acquired that model becomes a better and better approximation of the universe (and viceversa). The world is knowledge-friendly because it obeys the laws of nature. The human brain is knowledge-capable. Starting with the Enlightenment, the human brain decided to exploit this capability. The spirit of the Enlightenment provided the motivation that was missing. Knowledge allows the brain to build technology to help acquire more knowledge even about facts that the brain cannot experience directly. This chain reaction leads to an endless creation of knowledge.
Deutsch's argument that, assuming the universe is run by deterministic regular "laws of nature", a mind that can understand those laws of nature can in principle understand everything, is persuasive. However, he doesn't talk about the one feature of this universe that no science has been able to express, describe and predict with mathematical laws: human consciousness; which also happens to be the one that i'm sure about, and the one i care most about. Colin McGinn has argued convincingly that the human mind just might not be capable of understanding it, no matter what. Deutsch provides a general framework in which the human mind can understand everything that can be expressed in mathematical laws, but the doubt remains that some things will never be expressed in a formal, mathematical form.
The US philosopher John Searle makes a two-fold claim: consciousness cannot be reduced to the neurological processes that cause it, but is indeed a biological feature of the brain.
Brains cause minds, in his opinion, although we will not find feelings and emotions in the material processes of the brain, because feelings and emotions are higher-order features of the brain. Searle attacks the Cartesian tradition from the foundations: both dualism and materialism make no sense. The division of the world into matter and mind is arbitrary and counterproductive. In his view, we simply have to face the facts: consciousness is caused by brain processes, but consciousness cannot be reduced to those brain processes because it is a "first person" phenomenon and the brain processes are "third person" phenomena. To Searle, the mind-body problem has never existed: Descartes invented a vocabulary, a terminology, not a real problem.
In a similar vein to the school of "supervenience", Searle compares the mind-body problem to explaining how electricity arises from electrons or liquidity from molecules.
Searle is content with stating that consciousness is a (causally) "emergent" property of systems, just like electricity and liquidity. Searle realizes that liquidity can be predicted from the properties of elementary particles, whereas consciousness cannot be predicted from the properties of neurons. Searle realizes that Physics can explain how the features of electricity correspond to the features of electrons, whereas we can't explain (yet) how the features of consciousness arise from the features of neurons. Physicists can explain why (and exactly under which conditions) a set of molecules can achieve the phase transition to liquidity, whereas neurologists can’t explain when exactly non-conscious matter becomes conscious. Searle thinks that it is not just a limit of today's neurophysiology (likely to change with time), but that this will always be the case, that it is impossible to provide a material explanation of the features of consciousness. Searle thus admits a crucial difference between consciousness and electricity or liquidity or digestion: consciousness is special in that it cannot be explained.
Searle has nothing to offer other than declare that mental life exists and that it emerges from neurons, which is equivalent to saying that liquidity exists and that it emerges from liquids.
Searle thinks that computers have no minds because they are not brains, but he never proves the underlying assumption: that they are not brains. In Searle's jargon, "brain" is simply the "thing" that enables the mind. His entire theory can therefore be viewed as a mere tautology: the mind is due to the thing that causes it. What that thing is remains a mystery. Ultimately, Searle merely states that the mind exists. If one has not defined what a brain is, it is hard to claim that something is not a brain.
Searle basically resurrects Thomas Nagel's argument that consciousness cannot be explained. Thus, consciousness is not an emergent process like liquidity, because liquidity, like all emergent properties, is reducible to the physical process that creates it. Emergent properties are normally predictable by science: we know when (and why and how) a substance is a liquid and not a solid or a gas. If consciousness is indeed an emergent property, why should it be the only one that we cannot predict and explain?
Searle is not baffled by the emergence of conscious feelings from unconscious neurological processes of the brain. He finds it perfectly understandable. And therefore he downplays and ridicules all theories that tried to solve this paradox. But it is like somebody not being puzzled by the fact that the sun rises and sets every day, and contenting himself with the idea that it must be a feature of the Earth.
The Classical Theory of Consciousness
William James (at the end of the 19th century) was responsible for articulating the "classical" theory of consciousness, the equivalent of Newton's classical Physics. To James, consciousness is a sequence of conscious mental states, each state being the experience of some content. Just like Newton saw a unitary and continuous space, James saw a unitary and continuous consciousness.
James thought that consciousness must have an evolutionary purpose, just like Darwin thought that all features of the body must have an evolutionary purpose. Thinking is useful for our survival, just like eating and mating. James treated consciousness like a function, not an entity.
James was, in part, reacting to the theory of perception that dated from the 19th-century German physicist Hermann von Helmholtz, that sense data from the senses are turned by the “mind” into percepts which are conscious experiences of the environment. James thought, instead, that the output of brain processes is guidance of action in the environment, not a conscious experience of the environment.
Furthermore, James realized that every act of perception specifies both a perceiving self and a perceived object. Seeing something is not only seeing that object: it is also seeing it from a certain perspective. The perspective implies a "seer". A sensory act specifies not only the environment but also the self. Self (the "subjective") and the environment (the "objective") are two poles of attention. Each act of perception specifies both the self and the environment.
The self, in turn, is one but is also divided. The self is partly object and partly subject: there is a self who is the knower (the “i”) and a self who is the known (the “me”).
Consciousness in the Environment
In the 1930s the US biologist George Herbert Mead put forward a theory that, instead, located consciousness in the world, outside the organism.
For Mead, consciousness is not a separate substance, but the world in its relationship with the organism. Objects of the environment are colored, beautiful, etc: that "is" consciousness.
Objects do not exist per se: they are just the way an organism perceives the environment. And, presumably, different organisms may perceive different objects. Each organism perceives a different environment. It is our acting in the environment that determines how we perceive the environment. We are actors as well as observers. The response of the environment is what we perceive as objects.
In other words: the nature of the environment lies in its relationship with the organism; the environment results from the actions of the organism, in response to the stimulation of its sense organs, i.e. the organism determines the environment; and this results in the appearance of objects.
We are programmed to pick up organized information about the environment in the form of objects. The environment we perceive is merely a perspective of the real environment (that Mead calls "habitat"), one of the many that are possible. Each organism gets a different environment from the same habitat. The one world that we living beings inhabit is perceived in different ways (as different environments) by different organisms. This perspective is determined by the actions that the organism is capable of, by the set of its "organized responses". In particular, any change of the organism results in a change of the environment.
The organized objects of the environment actually represent our organized responses. They are what exists for us (for the kind of responses we are capable of). There is a direct relationship between our repertory of actions and our view of our habitat. Ultimately, the environment is a property of the organism as well as of the habitat. Those objects have qualities (such as colors) and values (such as beauty) that constitute what we call "consciousness". But, again, those objects and therefore their qualities depend on our repertory of actions.
Consciousness is a function, not a substance, and it refers to both the organism and the environment. It is located in the organism's environment, not in the organism's brain.
Consciousness is not a brain process: the switch that turns consciousness on or off is a brain process. Pulling up the blinds of a window does not create the street, it merely reveals it. By the same token, the brain can "pull up the blinds" and reveal consciousness, i.e. the set of objects and their qualities. Or it can pull them down, and consciousness disappears. The brain only has control over this switch.
Everybody has this kind of consciousness, but some species (and the children of our own species) cannot report on their experiences. It is social experience that makes awareness possible. It is not consciousness that enables socialization: it is socialization that enables consciousness (as awareness of one's experience).
Mead speculated that the individual views society as the "generalized other". The self arises from belonging to a group. The individual plays a role within the group. In fact, usually the individual belongs to many groups, and therefore plays many roles. Each role contributes to shape her or his self. The individual gradually integrates all these roles in one comprehensive view of her or his self, which is equivalent to saying that the individual takes the viewpoint of the "generalized other". More accurately, this constitutes the "me". Mead believed that we also have an "i", that is subjective and not socially constructed.
The self is created through socializing. A self is a contributor to awareness, and is aware of all contributions. A self always belongs to a society of selves. And a self is what she is as a member of that society of selves.
Likewise, the US biologist James Jerome Gibson used vision to explain what awareness is and what it is not. Body and mind constitute a false dichotomy. Awareness is both physical and mental. Awareness is a function performed by a living observer, the whole living being, not just its mind or its body. Awareness is a biological phenomenon. Perceiving is keeping in touch with the world. The observer is not external to the world, and therefore her/his awareness cannot be a state outside the world (i.e., in a different substance called "mind"). Cognition is a biological phenomenon, and it is both mind and body. Awareness is both mind and body.
Gregory Bateson believed that minds extended beyond bodies, that consciousness was not only in the brain but also in the surrounding environment.
The Czech psychologist Staninslav Grof thinks that we are not the makers of consciousness but merely the transmitters of it.
Sensing the Brain
Several models of consciousness focus on its behavior as a "sense" capable of perceiving the processing of the brain.
The British philosopher Nicholas Humphrey argued that to be conscious is to feel sensations, as opposed to perceptions. Animals have developed two ways of representing the interaction between the body and the world: "affect-laden" sensations and "affect-neutral" perceptions. Sensation and perception are separate and parallel forms of representation. Sensations are to be found at the boundary between the organism and the world and at the boundary of past and future. One "senses" a circle of light hitting the retina; one "perceives" the sun in the sky. One can have sensations about perceptions and perceptions about sensations.
Humphrey (“The Use of Consciousness”, 1967) speculated that we possess an "inner eye" that behaves like any other sense, except its object is the brain itself. This inner eye evolved because it was useful, and it evolved in such a way as to be useful. Therefore it does not deliver a one-to-one picture of the brain's activity, but a selected, abridged and biased one, as useful to survival as possible. Consciousness allows me to perceive the state of my brain as conscious states.
The US philosopher William Lycan is a proponent of consciousness as "internal monitoring", an idea that reaches back to the British philosopher John Locke and the German philosopher Immanuel Kant. Lycan emphasizes that most of our mental life is unconscious, that we are conscious of only part of it. A possible explanation is that consciousness is a perception of our own psychological state, of what is going on in the mind (Kant's "inner sense").
The British neurophysiologist John Eccles believes that consciousness resides in a psychological world that transcends the physical. Eccles believes that the mind is an independent entity that exercises a controlling role upon the neural events of the brain by virtue of its interaction across the interface between World 1 (the physical world) and World 2 (the mental world). The mind is continuously searching for brain events that are interesting for its goals.
The US linguist Ray Jackendoff believes that there are three main entities that account for our mental life: the physical brain, the computational mind (cognition) and the phenomenological mind (consciousness). The computational mind is the one that really "thinks", whereas the phenomenological mind only "feels" superficially a subset of the "thoughts". Most of "thinking" is actually unconscious. We are never conscious of the outer world, but only of the shadows of some of the processing that the computational mind does on the outer world. Consciousness arises from a level of representation that is intermediate between the sense-data and the form of thought, at the border between the representations of the inner and of the outer worlds.
The US psychologist Owen Flanagan does not believe in "one" consciousness, but in a group of "conscious" phenomena. Some of the processes of our body are unconscious and non-perceived (e.g., the heartbeat), while some are unconscious but perceived by other processes (sensors), and some are conscious, perceived by themselves. Consciousness is a heterogeneous set of processes, not a substance or an object. Flanagan’s theory is, de facto, a variation on William James’ stream of consciousness: there is no “Mind’s i” that thinks and is conscious, there are just thoughts that flow. Consciousness is not: consciousness flows. “The thoughts themselves are the thinkers”. I do not think thoughts, thoughts think me. There is no “i”: there is conscious activity. This conscious activity differs from the neural activity only in kind, but the mind “is” the brain.
Binding Brain and Consciousness
Knowledge about the world is distributed around the brain. How it is then integrated into one unitary perception is the "binding" problem.
This problem occurs at several levels. A sensory input is channeled through several different areas of the brain, each brain region focusing on one aspect of the input, but then somehow the mind perceives the whole input as something that happens at the same time in the same place, and it is a whole. The "binding" problem refers to how the brain creates the whole perception out of a sensory input that has been fragmented around the brain.
For example, a visual input is "split" so that one brain region analyzes the shape and one brain region analyzes the color. But somehow these separate pieces of information are joined again to produce the overall sensation of the image. At a higher level, different sensory inputs come together: the sound of an event is merged with the image of the event, or the smell of the event, or the touch of the event. The result is the overall feeling of the situation.
At an even higher level, the situation is merged with pre-existing memories and concepts. We don't only see a human being moving and speaking around us: we see our friend X talking to us. At the highest level, this entire complex system of feelings and knowledge "feels" unified in our consciousness. There is "one" feeling of "me" existing in a "world". Somehow all has been "bound" together into consciousness.
There are different theories about where and how and when this ultimate form of "binding" could occur.
“Space-based binding” is advocated by scientists who believe that there is a specific place in the brain where all information is integrated together. In the 1990s, a competing paradigm has emerged which is based on time instead of space, and is therefore referred to as "time-based binding": there is no particular place where the integration occurs, because integration occurs over the entire brain, and is regulated by some periodic process.
Space-based binding theories try to identify the "homunculus" in the brain that is responsible for running the integration process.
The working memory is a popular candidate for such a task, but no piece of the brain seems likely to show us the transformation of electrochemical processes into “feelings” (conscious processes).
According to the Portuguese neurobiologist Antonio Damasio, the story is more complex. There is not just one working memory: there is a whole system of "convergence zones". The brain has "convergence zones" and convergence zones are organized in a hierarchy: lower convergence zones pass information to higher convergence zones. Lower zones select relevant details from sensory information and send summaries to higher zones, which successively refine and integrate the information. In order to be conscious of something, a higher convergence zone must retrieve from the lower convergence zones all the sensory fragments that are related to that something. Consciousness of something occurs when the higher convergence zones fire signals back to lower convergence zones.
The Movie in The Mind
Damasio breaks the problem of consciousness into two parts: the "movie in the brain" kind of experience (how a number of sensory inputs are transformed into the continuous flow of sensations of the mind) and the self (how the sense of "owning" that movie comes to be).
The "core" consciousness of the “movie in the brain” is essentially unchanged throughout a lifetime, and humans share it with many other species.
On the other hand, the "extended" consciousness of the self is refined over a lifetime: an "owner" and "observer" of the movie is created within the core consciousness, in such a way that it seems to be located outside the brain, while it is part of the brain's neural processes and part of the movie itself which those neural processes generate. The more developed the sense of the self, the stronger the impression that the movie in the mind is "my" experience of the world.
Distinct parts of the brain work in concert to represent sensory input. Brain cells represent events occurring somewhere else in the body. Brain cells are "intentional” (the philosophical “intendo”): they represent something else in the body. They are not only "maps" of the body: besides the topography, they also represent what is taking place in that topography.
Indirectly, the brain also represents whatever the organism is interacting with, since that interaction is affecting one or more organs (e.g., retina, tips of the fingers, ears), whose events are represented in brain cells.
These two “orders” of representation are crucial for the rise of consciousness.
The "movie in the mind" is a purely non-verbal process: language is not a prerequisite for this first level of consciousness. The "i" is a verbal process that arises from a second-order narrative capacity.
The brain stem and hypothalamus are the organs that regulate "life", that control the balance of chemical activity required for living, i.e. the body's homeostasis. Consequently, they also represent the continuity of the same organism.
Damasio believes that the self originates from those biological processes: the brain is equipped with both a representation of the body, and a representation of the objects the body is interacting with. Thus it can discriminate self and non-self, and generate a "second order narrative" in which the self is interacting with the non-self (the external world). This second-order representation occurs mainly in the thalamus.
More precisely, the neural basis for the self resides in the continuous reactivation of 1. An individual's past experience (which provides the individual's sense of identity) and 2. A representation of the individual's body (which provides the individual's sense of a whole). An important corollary is that the self is continuously reconstructed.
From an evolutionary perspective, we can presume that the sense of the self is useful to induce purposeful action based on the "movie in the mind". The self provides a survival advantage because the "movie in the mind" acquires a first-person character, i.e. it acquires a meaning for that first person, i.e. it highlights what is good and bad for that first person, a first person which happens to be the body of the organism, disguised as a self.
This second-order narrative derives from the first-order narrative constructed from the sensory mappings. In other words, all of this is happening while the "movie" is playing. The sense of the self is created, while the movie is playing, by the movie itself. The thinker is created by thought. The spectator of the movie is part of the movie.
Consciousness is an internal narrative, due to those mappings. The "i" is not telling the story: the "i" is created by stories being told in the brain ("You are the music while the music lasts").
Consciousness As Self-Reference
The idea of some form of "self-referential feedback" (of some kind of loop inside the brain) is firmly rooted in modern space-based binding theories. Gerald Edelman's "reentrant maps" and Nicholas Humphrey's "sensory reverberating feedback loop" are variations on the same theme. The idea is that, somehow, the brain refers to itself, and this self-referentiality, somehow, unchains consciousness. Rather than "space-based", these theories tend to be "process-based", since they are not only looking for the place where the binding occurs but also for the way it occurs, and the process turns out to be much more important than the place.
According to Edelman, consciousness is a natural development of the ability to build perceptual categories (such as “blue”, “tall”, “bird”, “tree”, “book”), the process that we normally call generalization. The brain can do this because neurons get organized by experience in maps, each neural map dealing with a feature of perceptions (color, shape, etc.).
First of all, Edelman distinguishes between primary consciousness (imagery and sensations, basically being aware of things in the world) and higher-order consciousness (language and self-awareness).
For primary consciousness to appear a few requirements must be met. It takes a memory, and an active type of memory, that does not simply store new information but also continuously reorganizes (or “re-categorizes”) old information. Then it takes the ability to learn, but learning is not only memorizing, it is also a way to rank stimuli, to assign “value” to stimuli, to value one experience over another. A new value will typically result in a new behavior, and that is what learning is about. Then it takes the ability to make the distinction between the self from the rest of the world, i.e. a way to represent what is part of the organism and what is not. Then it takes a way to represent chronology, to order events in time. Finally, it takes a maze of “global reentrant pathways” (i.e., forms of neural transmission that let signals travel simultaneously in both directions) connecting all these anatomical structures. Primary consciousness arises from "reentrant loops" that interconnect "perceptual categorization" and "value-laden" memory ("instincts"). In general, cognitive functions emerge from reentrant processes.
Consciousness therefore arises from the interaction of two parts of the neural system that differ radically in their anatomical structure, evolution, organization and function: the one responsible for categorizing (external stimuli) and the other responsible for "instinctive" behavior (i.e., homeostatic control of behavior). Consciousness emerges as the product of an ongoing categorical comparison of the workings of those two kinds of nervous system.
From an evolutionary point of view, the milestone moment was when a link emerged between category and value, between those two different areas of the brain. That is when the basis for consciousness was laid.
A higher-level consciousness (being aware of itself), probably unique to humans, is possible if the brain is also capable of abstracting the relationship between the self and the non-self, and this can only happen through social interaction, and this leads naturally to the development of linguistic faculties. Edelman identifies the regions that are assigned to define self within a species (the amygdala, the hippocampus, the hypothalamus) and those that operate to define the non-self (the cortex, the thalamus and the cerebellum).
Note that, according to Edelman, concept-formation preceded language. Language was enabled by anatomical changes. What changed with the advent of language is that concepts became independent of time, i.e. permanent. And semantics preceded syntax: acquiring phonological capacities provided the means for linking the preexisting conceptual operations with the emerging lexical operations.
In Edelman's picture, consciousness is liberation from the present. Animals tend to live in the present, simply reacting to stimuli. Only conscious animals can think about the past and about the future.
As for the “place” where consciousness happens (its neural correlate), Edelman noted that consciousness is unified and a "whole", while nothing in the brain seems to be unified and a "whole": in fact, the brain is made of a multitude of regions that exhibit independent personalities. Consciousness must therefore be due to a global process that encompasses more than one region. He believes that the thalamocortical system originates such an activity: a massive, coherent (synchronized) activity by all regions of the brain, that transcends the individual activity of each region. Basically, consciousness is a process that happens throughout the brain, not manufactured in a specific region.
The location of consciousness is changing all the time, as different groups of interacting regions form and dissolve. At any moment in time, the “dynamic core” of primary consciousness is located in the interaction between the thalamus and the cortex. He does envision one particular region as being the permanent site of consciousness. In a sense, consciousness is the “process” not the “place”.
The Mundane Components of Consciousness
British neurologist Adam Zeman showed how mundane consciousness is: a little more or less of this or that chemical makes a big difference as to how you “feel”. Consciousness depends, mostly, on events that take place within the brain. A lack of this or that chemical is enough to alter our personality. After all, consciousness is a product of neural activity, and neural activity is a material process that uses material elements, which, ultimately, are the (indirect) constituents of consciousness.
By the same token, he describes perception as the brain’s reaction to being bombarded with energy picked up by the body’s sensors. Without that external energy, there would be no visual or auditory or any other kind of processing. Whatever the brain does, it is initiated by an energy impulse coming from the outside. It is then processed according to the chemical structure of the brain, which, by definition, depends on the amount and kinds of chemicals in the brain.
Zeman is quite convinced that the thalamus is the central site of consciousness. During sleep, the thalamus interacts with the cortex in rhythmic bursts, while inhibiting all sensory inputs. When the body is awake, the thalamus works as an intermediary between the periphery and the cortex, shuttling back and forth sensory inputs and commands to move. The brainstem is the switch that turns the thalamus on and off.
Zeman’s experiments raise the issue of whether consciousness is really a whole that cannot be reduced to components. Different neurotransmitters seem to contribute to different aspects of consciousness. If a neurotransmitter is inhibited, the person is affected, both physically and emotionally. If each neurotransmitter helps shape consciousness, can’t we also claim that consciousness is not a whole but, trivially, a sum of its parts?
Time-based binding does not look for the "place" but for the "time" at which the binding of our conscious experience occurs.
The German neurologist Christof Koch (“Collective Oscillations in the Visual Cortex“, 1989) discovered that at, any given moment, a very large number of neurons oscillates in synchrony, reflecting something that was captured by the senses, but only one pattern is amplified into a dominant 40 Hz oscillation. That is the "thing" the individual is conscious of. Out of so many oscillations of synchronized cells in the brain, one is special and happens to have a frequency of 40 Hz.
The British biologist Francis Crick originated the view that synchronized firing in the range of 40 Hertz in the areas connecting the thalamus and the cortex might explain consciousness; that consciousness arises from the continuous dialogue between thalamus and cortex. Awareness of something requires "attention" (being aware of one object rather than another), and attention requires "binding" (banding together all neurons that represent aspects of the object). Crick believes that binding occurs through a synchronous (or "correlated") firing of different regions of the brain. During attention, all the neurons that represent features of an object fire together. It is not just the frequency of firing of the neurons that matters, but the moments when they fire. The main difference between Llinas and Crick is in their background. Crick studied visual awareness and so is interested in consciousness that arises from external stimuli. Llinas, on the contrary, is more interested in consciousness that does not arise from external stimuli (what we call "thought").
Koch and Crick focused on the "neuronal correlates of consciousness" (NCC): the "thing" in the brain that corresponds to states of awareness. One of the first clues (although apparently disconcerting) is that much of the neural activity of the brain is not conscious at all: we are not aware of most of what our brain does. Most of the time (e.g., habits, instinct, etc.) the brain makes key decisions without "us" being conscious of those decisions.
Because most neuronal activity does not yield a state of awareness, they were led to believe that multiple forms of neuronal activity exist (this is almost a tautology). They speculated that one could potentially be conscious of many competing views, but only one "wins" the competition and results in awareness of the corresponding view.
All body cells are, to some extent, influenced by what happens to the body, but only a minority of the body cells represent external stimuli in an "explicit" manner: Koch and Crick believe that one is only conscious of features that are encoded "explicitly" by some neuronal assembly. The other way to find them is to listen to the way they oscillate. The electric potential of the brain as a whole exhibits oscillatory behavior in different frequency bands: the dominant rhythm for resting individuals is in the "alpha" band (8-12 Hz); the rhythm for normal cognitive activity is in the "beta" band (15-25 Hz) or, for more complex operations, in the "gamma" band (30 Hz or higher); sleep is in the "delta" band (1-4 Hz). Each of these "oscillations" is caused by some synchronous behavior ("firing") of many neurons.
The "binding" problem is the problem of how the various features are integrated in the brain into the perception of the object as a whole, especially when the same brain is integrating other features of other objects. The German physicist Christoph von der Malsburg (“How are Nervous Structures Organized?”, 1983) was the first to propose that synchronization could be the solution to the "binding" problem: the neurons working on one object are synchronized, and they are not synchronized with other populations of neurons that are working on other objects. There is one oscillatory behavior by neurons that seems to be associated with awareness, and it is in the 30-70 Hz range, with a peak around 40 Hz. Koch and Crick (“Towards a neurobiological theory of consciousness“, 1990) claimed that this oscillation accounts for consciousness (i.e., that the set of those synchronized neurons "is" the NCC for the current state of awareness).
Koch and Crick believe that several such "coalitions" of neurons exist at every point in time, and a sort of Darwinian selection determines which one (and only one) wins and results into awareness.
Another clue to finding the NCC is the cholinergic system: consciousness only occurs when there is an adequate supply of acetylcholine neurotransmitters, which are regulated by the brainstem (people whose brainstem is damaged lose consciousness).
The brain has a convoluted structure, and the way it represents an experience is even more convoluted, but we perceive an experience as a sequence of events. Koch thinks this has to do with the fact that, at every point in time, only one coalition is the winning one. It may change all the time, but we perceive an ordered sequence of events, because every other coalition that is active at the time is suppressed. We do not perceive the convoluted activity of the brain, which is analyzing an overwhelming amount of data, but only those events that correspond to the winning coalition.
Koch divides short and long-term memory based on the underlying mechanism: long-term memory is caused by a physical rewiring of the brain (strengthening of connections), whereas short-term memory is caused by a sustained firing pattern by an assembly of neurons. Koch proves that consciousness depends on the latter, not on the former. Short-term (or, better, working) memory could provide a sort of "Turing test for consciousness": any being that displays a working memory is likely to be conscious.
Koch also speculated on why we are conscious at all. After all, we do not need consciousness: the brain makes most of the key decisions in an unconscious way. The autonomic system directs the organs to do their job, and "instinct" helps the body survive. Qualia (the qualitative aspects of things) are "symbols" that help the brain synthesize, summarize, huge amounts of data. Seeing red or feeling pain are shortcuts to handling huge amounts of sensory data. Qualia are symbols that summarize the state of the world (including the body itself). This is the "executive summary hypothesis".
Koch believes in a non-conscious homunculus, residing in the front of the forebrain, that handles the information stored in the back of the cortex (the sensory regions) and that does all of the "thinking". The front of the cortex is looking at the back. This homunculus is beyond consciousness, the same way that automatic, zombie-like behavior is beyond consciousness, although one is "above" it (supramental) and the other is "below" it (submental). Consciousness is an intermediate level, which is conscious not of the homunculus and its work (its "thoughts") but only of representations of the homunculus' work in the form of inner speech.
Consciousness resides at an intermediate level, which is conscious not of the homunculus and its work (its "thoughts") but only of representations of the homunculus' work in the form of inner speech. We are not conscious of the homunculus that is making decisions for us, and we are not conscious of the real world. We are only conscious of the reality that we manufacture.
Time-Based Binding Abstracted
The US biologist Charles Gray then hypothesized (“Synchronous Oscillations in Neuronal Systems“, 1994) that the memory of something is generated by a stream of oscillating networks. Separate brain regions (corresponding to different categories of features) send out nervous impulses at the same frequency and the perception of an object is created by the superimposed oscillation. The brain uses frequency as a means to integrate separate parts of a perception. In this way the limited capacity of the brain can handle the overwhelming amount of objects that the world contains (the number of objects we see in a lifetime exceeds the number of neurons in the brain that would be needed to store them as images).
This theory is compatible with both Damasio's and Edelman's theories, as they all posit some type of "synchrony" for consciousness of something to emerge. According to these theories, it is time, not space, that binds.
Time-based binding almost marks a revival of “gestalt" psychology (the oscillation is, for practical purposes, a gestalt).
The Italian psychiatrist Giulio Tononi, however, noticed that one would therefore expect brain wave synchronization to increase with degrees of consciousness. Instead, when people lose consciousness, brain waves become more (not less) synchronized. Synchronized neural behavior reduces the number of possible states in which the brain can be. From the point of view of Shannon's Information Theory, synchronized behavior does not "add" but "reduces" the amount of information. Tononi believes that a better model for consciousness should focus on integrated information as obtained by the vast network of the brain (“Consciousness as integrated information”, 2008).
The Colombian neurophysiologist Rodolfo Llinas has interpreted these findings as a scanning system that sweeps across all regions of the brain every 25 milliseconds (40 times a second). The region of the brain containing the information about a sensation constitutes the "context" of an instance of conscious experience. The 40Hz oscillation provides the "binding" of such content into a unified cognitive act.
This wave of nerve pulses is sent out from the thalamus and triggers all the synchronized cells in the cerebral cortex that are recording sensory information. The cells then fire a coherent wave of messages back to the thalamus. Only cortex cells that are active at that moment respond to the request from the thalamus. Consciousness originates from this loop between thalamus and cortex, from the constant interaction between them. Consciousness is generated by the dialogue (or "resonating activity") between thalamus and cortex.
Consciousness is simply a particular case of the way the brain works. Other brain regions have their own temporal binding code. The motor system, for example, works at 10 cycles per second (which means that movements only occur ten times a second, not continuously). Every function is controlled by a rhythmic system that occurs automatically, regardless of what is happening to the body. Consciousness happens to be the phenomenon generated by that specific rhythmic system that operates on the brain itself.
Besides the 40-cycle-per-second, the brain has a number of natural oscillatory states: at 2 cycles per second it is sleeping. One of the brain's functions is to create images: at 2 cycles per second it creates dreams; at 40 cycles per second it creates images that represent the outside world as perceived by the senses.
In other words, the brain is always working independently of what is happening outside: during sleep, i.e. in the absence of sensorial data, that work is called “dreaming”; during the day, in the presence of sensorial data, it is called thought. The difference is that the brain’s automatic dreaming is conditioned by the senses: when the senses are bombarded by external stimuli, the brain can generate only some types of thought, just like the body can generate only some types of movement. At every instant, the brain is dealing with both reality and fantasy." A person's waking life is a dream modulated by the senses".
The US neuroscientist Paul Churchland provided a detailed description of how the brain perceives sensory input (in particular vision) through what he calls "vector coding". He claims that consciousness must be based on a "recurrent" network, and Koch's 40 Hz oscillation in the cortex is a convenient candidate for a brain-wide recurrent network. That brain-wide recurrent network would be able to unify the distinct senses in one consciousness.
In this sense, therefore, consciousness does not require language, and non-linguistic animals can be conscious too. Consciousness is biological, not social (its contents may be social, such as language).
What Edelman and Llinas have in common is the belief that higher mental functions originates from a process of loops that reverberate through the brain (in particular, between the thalamus and the cortex, the thalamus being the source of so many crucial signals and the cortex being the newer, more sophisticated part of the brain). Their theories differ in the specific mechanism that they use but they both focus on the fact that regions of the brain are connected in a bidirectional way and that they "resonate" in response to each other, they are somehow in synch.
There are other models that exploit the same paradigm.
The Chilean neurologist Francisco Varela has claimed that there is a primary consciousness common to all vertebrates. This primary consciousness is not self-awareness but merely experience of a unitary mental state. Varela thinks that it is due to a process of "phase locking": brain regions resonate, their neurons firing in synchrony, and create a cell assembly that integrates many different neural events (perceptions, emotions, memory, etc). This coherent oscillation of neurons is primary consciousness.
The US physicist Erich Harth tried to explain consciousness by means of a process that relies on "positive" feedback. Feedback can be negative or positive. Negative feedback is the familiar one, which has to do with stabilizing a process, in particular the input with the output of the process (e.g., thermostats and car engines). Positive feedback works in the opposite direction, at the edge of instability: the signal is amplified by itself, weakening the relationship between input and output. Harth thinks that a loop of positive feedback spreads through different areas of the brain and provides "selective amplification”. The loop basically joins the thalamus and the cortex, so that both send outputs that are inputs to the other. When input from the thalamus is stronger, the external world prevails. When input from the cortex is dominant, cognition prevails.
The British neuroscientist Susan Greenfield derived a definition of consciousness from her studies of mental infirmities: consciousness is the process of propagating a stimulus through a network of connected neurons, the same way one perceives the widening ripples created by an object falling in a pond.
She believes that, while there is no integrator of consciousness in the brain, nonetheless some type of "temporary" localization must exist. There is no site of consciousness, but consciousness originates from processes happening locally somewhere sometime. She believes that different groups of neurons take over at different times, a picture that resembles theories by Michael Gazzaniga and Daniel Dennett. Therefore, “consciousness” is multiple in space but unitary in time.
These groups of neurons she calls "gestalts": highly dynamic and transient, they are created by some kind of "arousal" and they are localized around an "epicenter".
She calls them "gestalts" because the dynamic properties of the brain "emerge" in a “gestalt” fashion from the connectivity of such neuronal assemblies.
An arousal can be an external (sensory) phenomenon or an internal (cognitive) phenomenon. The arousal causes the formation of a "gestalt" around an epicenter. The gestalt causes the "emergence" of a conscious event.
Each instance of consciousness arises from such a gestalt, caused by an arousal and localized around an epicenter. Overall consciousness develops from epicenters spread around the brain.
The passage from one conscious event to another conscious event, from one gestalt to another gestalt, which is typical of our inner life, is due to a ripple effect: the ripples of one gestalt's concentric action may act as an arousal and trigger another gestalt.
The size of a gestalt depends, first of all, on the strength of the arousal. But it also depends on the power of the epicenter to recruit neurons, a power that in turn depends on rival gestalts that all compete for neurons. The size of the gestalt has a direct meaning for us, because it corresponds to the depth of consciousness, to the intensity of the feeling.
During growth, epicenters tend to shift from "outside" to "inside", from external stimuli to internal associations.
Mental life is a dual process of searching for information and adaptation to information, the former leading to more conscious access, the latter reducing conscious access (things become habitual and automatic).
Consciousness "grows" as the brain does (from fetus to neonate to child to adult).
The Paradox of Attention
Attention is the process by which we focus on something. This sounds like an oxymoron, because the brain is always reacting to everything. Therefore it can't focus on "something". The sheer amount of data that enters the brain at every second is a distraction.
The brain is always processing everything that comes in, whether from the eyes or from the ears. The brain behaves like a machine reacting to all the inputs it receives. It doesn't have a choice: those inputs are transformed into electrochemical messages that cause electrochemical reactions spreading from the senses to the inner units of the brain. Limiting the brain's work to just one of these electrochemical processes is impossible. All the processes are going on at the same time, just because data hit our senses, and just because the senses always send signals to the brain, and just because every signal causes processing in the brain.
That is why, when we are driving and looking for a street in an unfamiliar neighborhood, we often turn down the radio. We cannot control the processing of the brain but we can control what data enter the brain.
Attention is a contradiction in terms.
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