"Every perception is to some degree an act of creation. Every active memory is to some degree an act of imagination."
Gerald M. Edelman
Gerald M. Edelman
Basic Books, 1989 - Medical - 346 pages
“A central thesis of Edelman’s work is that
the conscious moment exists because of its temporal interaction with that
already stored, just as the immune response of the body is quickened as a
function of past immunological challenges. Our experiences of the moment are
both existentially and physiologically related to what has come before. Anyone
who has read even the first M. Proust’s (1919) monumental work will easily
recall that it deals with the interactions odf past experiences onto the
current moment.”
Ralph M. Siegel
BioScience Vol. 41 No. 2 Feb. 1991 p. 113-116. (p 115)Journal of Cognitive Neuroscience, Fall 1990, Vol. 2, No. 4, p. 385-387 (p 385)
“According to Edelman, humans and some
animals possess primary consciousness consisting of phenomenal experiences like
mental images and qualia. Primary consciousness is bound to the measureable
present, brings with it no concepts of person, past or future, and cannot be
directly reported. The brain yields primary consciousness in Edelman’s terms as
a form of ‘remembered present’. Primary consciousness plus the development of
language in humans result in full-blown higher order consciousness, that
underlies direct awareness, personal identity over time, and a reportable
subjective life.”
John T. Bruer
A genuine understanding of how mental states arise from the structure and function of the brain would be, as William James declared in 1892, ”the scientific achievement before which all past achievements would pale.” Can a comprehensive biological theory of consciousness be constructed in 1990? Any attempt has to reconcile evidence garnered from such diverse fields as developmental and evolutionary biology, neuroanatomy and neurophysiology, cognitive psychology, psychiatry, and philosophy.Having laid the groundwork in his critically acclaimed books Neural Darwinism (Basic Books, 1987) andTopobiology (Basic Books, 1988), Nobel laureate Gerald M. Edelman now proposes a comprehensive theory of consciousness in The Remembered Present. Integrating findings generated by the recent explosive growth in the neurosciences with current knowledge of anatomy, cell biology, and psychology, Edelman has been able to construct a detailed model of how we become aware of our own existence.In addition to providing a scientific account of brain function and consciousness, the theory advanced in The Remembered Present will have a significant impact on a wide variety of fields. It provides a new outlook that may prompt fundamental revisions in the way linguists view language, physicians classify mental diseases, and philosophers look at the mind-body problem.
This book by Gerald Edelman is a very comprehensive and difficult to read book, one I've been able to get through, not so much based on my sketchy knowledge of neurology, but on my in-depth knowledge of real-time software design and recursive software. He uses his theory of neuronal group selection [TNGS] to create mechanisms for short term and long term memory storage.
In Roger Schank's Tell Me A Story, Schank offers a theory that all of our conceptual memory capability requires that we tell or relate the happening to ourselves or to another person. He makes a good case that, lacking such telling, the memory will be gone within weeks. That makes a lot of sense to me personally. As I try to recall specific episodes during a traumatic period of my life, when some things happened that I told no one, I find very little that I can recall. Only memories from that time are episodes of things I have since related to other people.
Edelman points out that memory is not placed in the brain as a content, but as a reentrant strengthening of synaptic connections, which by reinforcement during the re-telling, can come to the level of long-term potentiation (LTP) that would create what we call permanent memories. If a memory of an event is reinforced by relating it to others, it stays in the same place, but that place becomes easier to visit with each relating. That's why a District Attorney will question witnesses over and over again before the trial. It's so that what they say at the trial will be easier to recall if they repeat what they had said to the DA before the trial. The idea is to reduce the possibility of some unexpected memory coming up during the trial
In Edelman's TNGS the places or paths are the memories themselves. The content of the memories is the way to retrieve them [we call this: associative memory] and the process of retrieving the memories is the content of the memories. What happens as you begin to think of the memory is that your brain activates certain neuronal groups, which activation helps you to create the memory you desire. It also helps you to strengthen its later recollection.
The title Recategorical Memory would be more appropriate for this book which is filled with long strings of sesquipedalian phrases, such as reentrant cortical integration, anatomically mapped reentrant connectivities, andinteroceptive homeostatic regulation. The title phrase "The Remembered Present" says it short and sweet: the biology that creates consciousness does so by recovering the past in the present, comparing the past with the present, and re-storing the modified conception. Note the way that Edelman says a similar thing on page 102:
"Primary consciousness may thus be briefly described as the result of the ongoing discrimination of present perceptual categorizations by a value-dominated self- nonself memory. My main focus was on perceptual categorization as it related to memory and learning. I proposed that these functions could be understood in terms of "neural Darwinism" — the idea that higher brain functions are mediated by developmental and somatic selection upon anatomical and functional variance occurring in each individual animal. I proposed that this ability depended critically on two of the most striking features of the brain, its variability and its reentrant connectivity.
Perception [now] = Function [ Perception [now], Perception [past]]
If no comparison took place between value and past categorizations to form a special memory, consciousness would not appear.
"
Edelman says on page xvii, talking about his work leading up to the current book:
Later, on page xviii, he adds:
These two features he has masterfully combined in his Theory of Neuronal Group Selection or TNGS, which is described in detail within this book. The Remembered Present gives a bio- theoretical basis for an insight that I had some twenty years ago as expressed by the following equation:
Value he defines on page 287 referring to: "evolutionarily or theologically derived constraints favoring behavior that fulfills homeostatic requirements or increases fitness in an individual species." Thus value is the "special memory" that was selectively laid down in neuronal groups in the past during comparisons of past values and past categorizations.
This process is easier to understand directly from my equation above. Our perception of the now is a function of our total past categorizations and our perception of the now. What we perceive now is a function of the perceptions made available to us now from our exterior surroundings (nonself) and the sum of our past perceptions stored in our interior self. What we perceive is influenced both by our individual past inputs and the inputs coming into us now. Think of a file that you keep in a drawer, and every time you take the file out to look at it, you make a note on it before you return it to the drawer. This will give you a sense for what happens when we perceive something: we change our ability to perceive.
The equation is reentrant because the result Perception [now] appears inside its own evaluation. Each time a new perception is received a slight alteration to the neuronal groups is laid down, and this alteration becomes the Perception [past] . When a Perception [now] comes in, the alteration to the neuronal group continues: it is added in with the newPerception [past] and creates a new resultant Perception [now] . In a sense, what we call we is the correct condition of our neuronal groups as they have integrated all our idiosyncratic experience for us since the moment of conception.
When Virgil, a fifty year old blind man recovered his sight, he went from a competent sightless adult to a handicapped sighted person. [See ARJ: An Anthropologist on Mars] He spent hours turning over toy automobiles, skyscrapers, and animals, inspecting them from every angle, over and over again, like a toddler at play. What looked like child's play to others was a very serious endeavor on Virgil's part to be able to perceive the objects in his brand-new real-world visual environment. He needed, in order to become a normally functioning sighted person, to be able to separate objects from the camouflage mazes of background colors and patterns they were embedded within. His sister painted a white line through his living room so he could walk through with his eyes open. If Virgil followed the line the room looked normal -- if he deviated to one side or the other, the entire room collapsed into indecipherable mazes of patterns for him, and he would stumble and fall in a room which he could easily navigate with his eyes closed. He was, by playing with the miniatures, creating for himself a Perception [Past], one which he had been deprived of by his childhood blindness.
The process described by the equation is important when one considers dogma, the accepted body of one's beliefs: it is also a Perception [Past]. The process is neuronal group selection all the way down, or rather all the way back to our conception. Each event after the initial fertilization of the egg that created us adds its spin on the evolution of our individual nervous systems, our individual perceptions, and our individual beliefs.
The Reader may wonder how it's possible for perception of the past to affect perception of the present. Given two good sets of eyes, two people looking at the same object will both see the same thing, won't they? Not necessarily so. When Charles Darwin's ship, the Beagle, anchored off South America, the native peoples there had never seen any boat bigger than a canoe. When asked by Darwin's men what the natives thought about their big ship, the natives said, "What ship? That's a sea bird!" That was all their Perception [Past] allowed them to see.
One key concept in the philosophy of mind when considering whether consciousness exists is called qualia. As he gives the definition on page 166, qualia are "the various subjective experiences, feelings, and sensations that constitute or accompany awareness." There are two parts to the qualia: feelings and sensations. 1.) Feelings are the re-triggered physical body states originally stored before the Memory Transition Age [about five years old]. This is a major tenet of the new science of doyletics, the definitive book on which is yet to be written. [See ARJ: PANACEA!, Emotional Intelligence, Passion & Reason, Emergence, and Thinking in Pictures.] 2.) Sensations, as subjectively experienced, are not capable of being shared objectively, only correlated with our own and other's experiences. This can be stated simply: We do NOT see the same color red, and we are helpless to prove otherwise.
The sum of all these, we call, along with Edelman, consciousness. Lacking a Perception [Past], animals lower than primates do not possess consciousness. Let me explain how I arrived at my conclusion in 2.): I have four television sets in my Screening Room and have had the same video on the four screens many times. The color red is always different on each of the four TV's, and although I could make the red color get close on one or two of them, they were never the same color. Why? Differences in aging of the red phosphor in the screen, voltage differences between sets [high voltage supplies also age], and manufacturers' designs account for the differences in the red colors of the four sets.
It should be obvious that our eyes are subject to equivalent sorts of variation due to aging and manufacturers' designs [genetics] and that would cause each of us to experience a different subject color of an object that we would each agree to call red. A TV camera points to a red object and displays the same object on four screens and we see four different colors we call red on the four sets. To do the same experiment with humans we place four people in a room to view the same red object. We can assume that each one of them sees a different shade of red. The insurmountable problem is that no one can see all four of the shades they see. There is no position from which we can view, like the TV sets, all four views of the object. Each person sees a different shade of red, each calls it red, and they all agree that they see the same shade of red as the others. But they are probably wrong and we can never prove otherwise. A moment's reflection will lead you to see that we cannot even say that each of the four people see a shade of what, if we could ever see it, we would agree is red. One of the four might unknowingly have color blindness and be seeing green. But that is a form of color variance that can be tested for: one need only present information to them in which the context of the color is removed and they cannot make a distinction. The number charts do this quite well. There is no test for the variance in color perception I'm talking about because the person sees a given wavelength of light, perceives a color [whose shade we don't know andcan't know], and calls it red. Everyone else who sees it calls it red, but we cannot compare what they are seeing from an objective point of view. We have only their report of their subjective experience. We do NOT see the same color red, and we are helpless to prove otherwise. The same helplessness applies to all of our other perceptions. We can describe them, but others cannot experience our perceptions, only their perception of what we describe.
Descartes viewed the world as two realms which he called mind and matter. In Descartes' view perceptions were stimuli from the world of matter that were presented to world of mind inside the brain. This view has had a long standing philosophical problem: it requires inside of the mind what it presumes to explain, that is, a fully functional human being looking at the perceptions being presented inside of the mind. This is the problem of the homunculus, a little man inside our brain. What Edelman has done is to create a biological theory of consciousness which eliminates the homunculus and its infinite regress. What he replaces it with is a biological level of recursion in which the infinite regress is replaced by an infinite progress, if you will. At each moment the perception of the now is compared to the perception of the past and a new perception of the past is laid down in one's neuronal groups. Edelman leads us to see that we live always in the remembered present. In this equation the term Perception [past] refers to the integrated sum of our past perceptions (created by using this same reentrant equation). The exact function is unspecified, but may be considered as a comparison of two memory traces: one accumulated over a long period of time and one generated from the instantaneous sensory input being received. Edelman refers to the Perception [past] term as past categories.
The Remembered Present: A biological theory of consciousness
By Gerald M. Edelman. 346 pp., illustrated, New York, Basic Books, 1989. $29.95.
We are the creatures of language and awareness, the ones whose biologic makeup makes possible the writing of a review such as this, not to mention a book such as Gerald Edelman's The Remembered Present, an effort to explain what happens in the brain that ends up being called by us a state of consciousness. No small ambition has prompted this book from a distinguished neuroscientist, especially at a time in our history as a species when we understand every other part of the body far better than the brain — even as it is this very brain that has given us our knowledge of all the other organs in the body. Still, Dr. Edelman has taken the risk every theorist assumes: he has presented us with a vision of things, with the acknowledgment that a future factuality may well prove him somewhat or way off the mark.
Dr. Edelman distinguishes between "primary" and "secondary" consciousness. He suggests that the former (present in young children and in animals such as apes or dogs) has to do with physiologic need — hunger, for instance — as a stimulus to awareness. He locates, of course, distinct areas in the brain where such needs, or drives, are situated and corresponding areas where the external world's sensory input is received and makes its impact. "Secondary consciousness" is quite another matter — it has to do, he tells us, with our unique human capacity for language, for the complexities of reflection, for analysis of oneself and others, and for the knowledge of life's finite nature, its ironies, and ambiguities; in other words, it is the consciousness that results in a book such as his, indeed in all books.
Not that we are anywhere near a biologic understanding of this wondrous human gift of language. Like many others, Dr. Edelman has to settle for historical speculation and for the blanket designation of certain areas of the brain as essential to our ability to use language. His theory of "neural Darwinism" (spelled out three years ago in a book with that title) asserts "major evolutionary adaptations in anatomical structure underlying the capacity for speech." But those "adaptations" took place in a particular species — or as Dr. Edelman puls it: "While this theory of language acquisition is based on the evolutionary emergence of special anatomy, it is clear that this anatomy must necessarily have been linked in its function to already sophisticated areas in the brain capable of concepts."
Not that the author knows how those areas of the brain work to give us our various concepts, including the ones he offers in his book. If we had such knowledge — of the neurobiology of conceptual thinking — we obviously would not be immersing ourselves in Dr. Edelman's speculations, some of them put into elaborate flowcharts, others put into fairly dense assertive statements, and still others offered as offhand observations or asides that sometimes tell everything and nothing. For example: "The neural connectivity of motor and sensory systems can account for signing and for the language learning of deprived individuals like Helen Keller." Yes, certainly, but still we are in awe of what she did, of the communicating being she became, even as we are in awe of what happens to small children when they start using words. To state that "neural connectivity of motor and sensory systems can account for" such aspects of our humanity is to tell us, I fear, how little we yet understand about our distinct neurophysiologic nature. As Dr. Edelman is frank to admit, "a very large gap remains in our understanding of the biological bases of psychological phenomena." Even so, we are somewhere in the history of our intellectual life when a book such as his strikes many readers as a brave statement of the limits of our knowledge as well as a prophecy of what kind of research will make a difference in the future.
The Remembered Present is not an easy book to read; the subject matter is daunting, and the author's admirable attempt to write plain, accessible prose keeps foundering on the shoals of his exceedingly complex neuroanatomical conjectures, not to mention his ventures into a "biologically based epistomology." On the other hand, there are rewarding moments, when the reader begins to glimpse with a new clarity how the evolution of consciousness and language both may have taken place, and where (in broad terms, neuroanatomically) those attributes are to be found taking place. There are also delightful admonitory moments that some of us in a hurry to integrate all possible "levels" of knowledge might keep in mind and make part of our consciousness: "It is a long way from acetylcholine to the incest taboo." Needless to say, that "long way" will only be made shorter by decades of neurobiologic research rather than theory making. And yet, Dr. Edelman's formulations will help some of us to think about where we are now, with respect to our neuroscientific knowledge, and where we need to go. Put differently, his book will become part of the consciousness of some of us, the very consciousness he aims so earnestly to comprehend and that can be mindboggling and humbling when existential reflection takes place: the whole planet is a mere spot in an infinity of space, and the entire span of our self-awareness is a mere moment in an infinity of time.
Robert Coles, M.D.
New England Journal of Medicine 1990; 323:839-840September 20, 1990
