55 of 60 people found the following review helpful:
5.0 out of 5 stars
Reconciling brain science and human concern: a timely addition to one of the most distinguished bodies of work in neuroscience, May 5, 2007
This review is from: Second Nature: Brain Science and Human Knowledge (Hardcover)
Will knowing how the brain works--in particular, what consciousness is--transform our view of human knowledge itself? This is the question that looms large in Second Nature, Gerald Edelman's latest book. Though compact at 157 pages (excluding preface, footnotes, and index), this work represents Edelman's ambitious consideration of the implications of his view (likely the correct view) of the brain and mind for the broader world of human concern. Edelman seeks to understand the nature of knowledge as it is generated within a biological entity--the brain--that is shaped both by individual history and evolutionary forces. Astonishingly, in this little book, he succeeds in this quest marvelously. The result is no less than a new type of epistemology--what Edelman refers to as "brain-based epistemology."
Gerald Edelman is no mere dilettante or interloper in neuroscience. Since the publication of The Mindful Brain (a volume he co-edited and co-authored with Vernon Mountcastle) nearly thirty years ago, Edelman has diligently toiled in the theoretical vineyards to construct a comprehensive theory of higher brain function that is consistent with the latest available neuroanatomical, neurophysiological, and behavioral data. Perhaps the most significant fruit of these labors, the Theory of Neuronal Group Selection, or Neural Darwinism, proposes that, during neurogenesis, a vast "primary repertoire" of physically connected populations of neurons arises. Later, in a process akin to Darwinian selection, a "secondary repertoire" of functionally defined neuronal groups emerges as the animal experiences its world, and that world in turn selects patterns of connectivity (the so-called neuronal groups) that provide a good enough fit in a given moment to engender some kind of positive outcome. Underlying this selection is a neural "value system," established over the course of evolution and believed to comprise small populations of neurons within deep brain structures, that assigns salience to particular stimuli encountered by the animal. When the response to a given stimulus leads to a positive outcome (i.e., eating satisfies hunger), the value system will reinforce, or strengthen, those synaptic connections between neurons that happened to be firing at that particular moment. There is now a greater likelihood that, when the animal encounters similar stimuli in the future, many of the same neurons that fired the first time will fire together again. When a stimulus is noxious, the value system will similarly strengthen the connections between neurons that happened to be firing at the time the stimulus was encountered, thus increasing the salience of that stimulus. When a stimulus has no salience, synaptic connections between neurons that fired upon first exposure to that stimulus will become weaker with successive exposures. Simply stated, neurons that fire together wire together. Keep in mind that the mapping of the world to neural substrate is degenerate; that is, no two neuronal groups or maps are the same, either structurally or functionally. Nor are the populations of neuronal groups that make up the neural mappings of the world exactly the same each time similar stimuli are encountered. These maps are dynamic, and their borders shift with experience. And finally, since each individual has a unique (and privileged) history, no two individuals will express the same neural mappings of the world. Indeed, from the establishment of the primary repertoire during development, no two brains are wired in exactly the same way, not even those of identical twins.
Notwithstanding any of the various attempts at historical revisionism that you may have encountered if you've read broadly across neuroscience and the philosophy of mind, the selectionist view of the nervous system begins with Edelman's highly original work. What follows from others making selectionist arguments is (whether they like it or not) purely derivative.
Although Edelman's theoretical framework has expanded to include the Dynamic Core hypothesis, a proposed mechanism for consciousness (See Edelman and Tononi's A Universe of Consciousness) that he discusses throughout Second Nature (and I will not unpack here), I believe that Neural Darwinism is his most fundamental contribution to modern neuroscience. To this day, it remains the most detailed and comprehensive theory of higher brain function ever proposed. Perhaps most importantly, and likely to the great consternation of those critics capable of lobbing only ad hominem attacks at Edelman himself, the theory is, in the best traditions of empirically grounded science, eminently testable. I have laid out a brief (and wholly inadequate) sketch of Neural Darwinism here because many of the critiques of Edelman's work are colored either by misapprehensions about this theory or the unrealistic expectation that its underlying mechanism can and should be easily described and readily digested. But unless you can appreciate the vast complexity of a biology shaped by evolutionary principles that are not well understood by the lay public (or even some scientists, for that matter), you will probably struggle to understand much of what Edelman has to say, even in this little book. The fault lies not in Edelman's prose, but rather in the nature of the subject matter he seeks to describe (contrary to the complaints of a few critics--see below). Persevere; if you love biology, are fascinated by the mysteries of the brain, and are curious about the implications of modern brain science for the nature of human knowledge and endeavors, then this book should be your touchstone.
I'm not going to give you a detailed rundown of the contents of Second Nature here; I'll simply recommend that you read it. In the remaining paragraphs, I hope to provide you with something I think will be of even greater value: a discussion of some of the most commonly raised criticisms of Edelman and his work. I hope that this will allow you to read the book--if not totally free of misconceptions--at least less encumbered by what I believe to be unfair attacks on one of the most constructive and distinguished bodies of work in modern theoretical neuroscience.
It is curious that Edelman's work engenders as much vitriolic reaction as it does. If you've read my review up to this point, you've certainly concluded that I'm firmly in Edelman's camp. That said, what follows are the most common claims about Edelman and his ideas from his most vocal critics. These can be clearly stated and quite easily dispensed with. In no particular order, here they are:
1) There is nothing original in his ideas.
2) Natural selection is not an apt analogy for what the brain does.
3) His models are instantiated on computers even though he claims that the brain is not a computer (look up the review by George Johnson).
4) He doesn't understand, or mischaracterizes, the views of modern philosophers.
5) He denigrates philosophers and their work.
6) He omits the work of others.
7) He doesn't communicate his ideas effectively, i.e., he does not write clearly or well.
Now, my rejoinders to the above claims:
Claim #1: Quite simply, those who make this claim need to practice better scholarship. Edelman first suggested the idea of neuronal group selection nearly thirty years ago. Back in the late 1970s, no one else in neuroscience ventured any such selectionist ideas. Moreover, early on, Edelman took quite a lot of heat for this notion. His transition from immunology to neuroscience, though logical from a theoretical perspective (moving from one selectional domain to another), may have offended stalwarts of the neuroscientific establishment. In any case, later, when the evidence suggested that Edelman was indeed correct about competition among groups of neurons (see, for example, the work of M. Merzenich), the attitude of many within and outside of neurobiology was something along the lines of, "oh yeah, but of course there are competitive interactions between functional neuronal assemblies; everybody knows that!" Well, clearly not everybody, and certainly not back in 1978. Over three decades, an original idea had thus been unfairly relegated to derivative status. It wasn't derivative; it was the source.
Claim #2: There is much evidence to suggest that neural representations of the world are dynamic and based on the competitive interactions between functionally defined and degenerate (e.g., non-identical) groups of neurons. Many alternative views of the central nervous system (CNS) have invoked formal computational principles. But everything we know about the CNS suggests that it functions nothing like a computer. If it were a sort of Turing machine, it would represent the only such example known to biology. Most modern biologists steeped in evolutionary principles (whether strictly Darwinian or of the Punctuated Equilibrium variety championed by Stephen Jay Gould and Niles Eldredge) would probably balk, first, at the notion of the emergence of organized populations of cells (or proteins or molecules, for that matter) capable of executing computations in the same manner as a digital computer, and second, at the idea that this sort of arrangement, if it had appeared at all, would have appeared only once over the course of evolutionary history. Finally, a challenge to those who too easily dismiss Edelman's Theory of Neuronal Group Selection and all that has followed from it: Go ahead and TRY to formulate a detailed, testable theory of brain function that takes account of the underlying biology of the central nervous system. Any takers? No? Enough said.
Claim #3: A number of Edelman's critics, such as the science writer George Johnson (Miss Leavitt's Stars), see little...
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44 of 52 people found the following review helpful:
3.0 out of 5 stars
"Second Nature" is a good read but not a very good contribution, December 28, 2006
This review is from: Second Nature: Brain Science and Human Knowledge (Hardcover)
Printed small, Edelman's "Second Nature" is a bit-sized flight through how consciousness relates to larger cultural phenomena. This book is supposed to be a bridge between neurobiology and philosophy.
Edelman coins the term "brain-based epistemology" which he calls an extension of W. V. O. Quine's naturalized epistemology (pg. 2). Edelman also says that he follows in the footsteps of William James who said that consciousness is a process whose function is knowing (pg. 4).
Edelman has 3 graphs (2 on pg. 16 & 1 on pg. 29). The 1st graph is a rudimentary localization of cortical functions, the 2nd graph is a rudimentary visual of synaptic connections, and the 3rd graph is a simple (but important) directional illustration of "Reentry." For Edelman, the brain is a selection system which selects based on an evolutionary drive. "Neural Darwinism," which Edelman says has 3 tenets basically refers to the plasticity of brain development and processes. "Reentry" is the most important part of Neural Darwinism because "reentry in the enormously complex dynamic core distributed to the thalamus and across the cortex was the key integrative event that led to the emergence of conscious experience" (pg. 39).
Much of the book's middle is dedicated to finding a place where the modern divide between the literary and the scientific (Edelman is here borrowing from C. P. Snow) can meet. In order for the arts to meet the sciences the arts much respect the divide between "ought" and "is," and the "qualified realism" (pg. 154) where the scientific method (i.e. Edelman's "Neural Darwinism") is the best method to practical truths about beings and things) while the sciences must admit that ontological quality of "Qualia" (Edelman draws here from Thomas Nagel's ""What is it like to be a bat?" in Nagel's book "Mortal Questions") and science must admit that a "fully reductive scientific explanation" of the humanities is "not desirable, likely, or forthcoming" (pg. 66).
Furthermore, the "underlying historical processes" of our epistemic condition "rule out simple reduction" to scientific description (pg. 87). This can be seen as a critique of Paul Churchland's materialistic approach and Daniel Dennett's similar "heterophenomenology." Edelman aligns with John Searle when he says that "consciousness is a first-person affair" (pg. 89). This leads me to my first critique of Edelman....
Edelman reiterates the Humean "naturalist fallacy" of deriving an "ought" from an "is" when in fact John Searle has written particularly on this subject in his essay "How to Derive "Ought' from "Is'" (1st published 1964) showing that the Humean fallacy must be reappraised. Edelman refuses to recognize Searle's nuanced discussion in his text and/or in his footnotes. Secondly, if we take Edelman's notion seriously that "Science derives from a variety of cultural events and it generally does not necessarily impel or predict such events...it is as good as we can get" (pg. 156), then we must understand that Neural Darwinism is just one way among others of coping with whatever reality is, it just happens that so far Neural Darwinism is the best way to cope. Edelman seems to hint at this while at the same time he prioritizes science: "The main strength of the brain-based approach is that it provides scientific grounds for a pluralistic view of truth" (pg. 148). Edelman seems to be vaguely conflating a best approach and the "True" approach. The problem, again, is his hard-and-fast line between "Is" and "Ought." (So for example, the debate between evolutionists and creationists should not be over "Truth" but instead over what John Dewey calls "warranted assertability"). Edelman should argue instead that since brain-based epistemology explains that we are probably selectionalistic dynamic systems in an econich and culture it follows that our knowledge of Neural Darwinism is not so much a discovery as the best available way to cope with phenomena. If Edelman truly wants to "follow in the footsteps of William James" then he'll find this criticism a reasonable corrective.
Another criticism: Edelman wrongly conflates Richard Rorty and Charles Taylor on a sensitive subject dealing mental representationalism and embeddedness in the world (pg. 45-46). Rorty is known, in part, for his attack on representationalism and Taylor is known, in part, for his defense of a kind of Heideggerian embodied-embedded approach. However, Taylor, attacks Rorty's approach with his own essay "Rorty and Philosophy" in the book "Richard Rorty: Contemporary Philosophers in Focus." Edelman presents Rorty and Taylor together like an undergrad presents Plato and Aristotle together (meaning the glaring differences go unnoticed under the heading of "the Greeks").
Another criticism: Edelman spends only one paragraph on the problem of free will (pg. 94). This is shameful. Better literature on free will includes Daniel Dennett's "Freedom Evolves." Another approach (more like Edelman's approach) is John Searle's "Freedom and Neurobiology."
Overall, this book talked very little about our "Second Nature." The author cited sources poorly. In order to dissolve C. P. Snow's dichotomization in "The Two Cultures" Edelman is going to have to write more than 157 bit-size pages.
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59 of 72 people found the following review helpful:
2.0 out of 5 stars
Edelman needs an editor, January 25, 2007
This review is from: Second Nature: Brain Science and Human Knowledge (Hardcover)
This is the second Edelman book I've read, which was supposedly for a popular, albeit educated, audience, and like "Wider Than The Sky", I found his prose uniquely bad and off-putting. I've read loads of books now on the mind, from Searle, the Churchlands, Fodor, Pinker, Ramachandran, Gazzaniga, et al, and all of them are able to express themselves clearly even when discussing sophisticated concepts. But for me, reading anything by Gerald Edelman is a terrible chore - like some crazy reading comprehension test devised by a sadist - rather than an exciting journey through a brilliant mind. Indeed, I wondered a few times reading this book if Edelman might even feel a perverse pride in keeping his writing below the average standards of intelligibility.
Australian philospher David Stove once remarked that he very much appreciated the contributions of John Stuart Mill, because while (he thought) Mill was wrong, his ideas were expressed with great clarity, allowing them to be more easily evaluated (which in turn facilitated greater understanding). Edelman must be a smart man, so I wish he was able to more effectively communicate his ideas. When so many of his colleagues can do it, I don't know why he can't.
Addendum Mar. 10, 2007: I just read John Horgan's book "The End of Science", and was surprised to find a section on none other than Edelman himself. I was even more surprised (and frankly, sort of thrilled) by the quotes there from Edelman's peers (like Daniel Dennett and the late Francis Crick), on the incomprehensibility of Edelman's gobbledygook (in the back of my mind I was still wondering whether it was just me...). In fact, one fellow scientist expresses his judgment that Edelman tries to disguise unoriginal ideas through the use of rhetorical bluster, pedantry, and new names.
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