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The Symbolic Species: The Co-Evolution of Language and the Human Brain

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Three reasons to read "The Symbolic Species". 1) Deacon describes how neuroscience is finally producing results that deal with the issue of how brains make human language possible. 2) Deacon presents a theory of brain/language co-evolution that stresses the importance of behavioral innovations that alter the human environment leading to subsequent genetic adaptation. 3) Deacon explores ways by which Philosophy of Language can be refined by incorporation of results from the scientific study of human language.

This three-fold enterprise depends on the neuroscience results discussed in Part Two of "The Symbolic Species". For example, Figure 7.8 draws our attention to the idea that prefrontal cortex is disproportionately large in the human brain. Deacon suggests that changes in the relative sizes of brain regions during human evolution is a mechanism for adaptations that allow humans to better perform language tasks. Figure 8.3 pictorially illustrates an evolutionary trend in anatomical connections towards more direct cerebral cortex control over the motor neurons that are involved in vocalizations. These examples illustrate the fact that Deacon's theory of brain/language co-evolution is heavily dependent on comparative studies of brain anatomy. Deacon tries to convince us that the major anatomical changes during human brain evolution are the precise types of changes in an ape brain that would facilitate human language behavior. According to Deacon's theory, early humans started using language as a social innovation and then the human brain changed so as to make it easier to use human language. The fact that human social interactions are a huge part of the human environment guarantees that there has to be some truth in Deacon's theory, but is it just part of a larger story?

A specific issue that Deacon touches on is the fact that non-human apes are able to learn the basics of human language simply by being exposed to a social environment where human language is being used. Why do non-human apes learn the basics of language rapidly and then stop developing more sophisticated language behavior just at the developmental stage where human children are taking off with a huge vocabulary and increasingly complex syntax? The best that Deacon's theory can suggest is that humans, unlike chimps, have had 2 million years of language use and subsequent brain evolution in response to selective pressure for larger brain regions that aid in symbolic thought. I agree that it would be astounding if certain brain regions such as the adult human prefrontal cortex is not more useful for human language tasks than is the chimp prefrontal cortex, but is this really the most important thing we need to know about the relationship between brains and language?

Is there another way of looking at the difference between human and chimp brains? One that might better inform us about the functional differences between human and chimp brains that give humans superior language skills? Deacon mentions an alternative in Chapter 6, "...the rate of human brain maturation...is prolonged compared to other primates..." In fact, most human brain growth happens after birth while most chimp brain growth happens before birth. What does this have to do with language behavior?

Perhaps everything. Why DO humans have big brains? Even though Deacon correctly points out the fact that, in the case of brains, bigger does not mean better, his whole theory ends up depending on the idea that by making some brain regions bigger, you get an ape that is better at learning human language. Deacon tries to gloss over this contradiction by assuring us that his theory is really making use of a powerful mechanism for evolving a more language-competent brain, the mechanism of "parcellation", which he claims can mechanistically explain data such as those given in Figure 8.3. Can parcellation really do all the explanatory work that his theory demands or is there a need for additional mechanisms?

Why DO humans have big brains? What if big human brains are just a side effect of some other more important aspect of brain physiology? What if larger human brain size is just a side effect of evolutionary selection for prolonged synaptic plasticity during human childhood? Maybe if we could alter a few genes in bonobos so as to prolong postnatal brain growth in certain bonobo brain regions like the anterior cingulate cortex, just maybe we would give bonobos a longer window for developing sophisticated language skills.

There is a whole tradition within neuroscience that started with behavioral studies of associative learning and led to studies of the cellular and molecular mechanisms of learning and memory. This branch of neuroscience research is almost completely ignored by Deacon. We have to wonder if Deacon's focus on neuroanatomy has provided him with a limited data set which paints his theory of brain/language co-evolution into a corner.

So my advice is that people who are interested in language should read Deacon's book, but recognize the limitations of his perspective. In the next few decades the rest of the story of how brains make human language behavior possible will come rolling in. Deacon has provided us with a working model of how to apply this hard-won knowledge of the brain to our understanding of human language, but Deacon's is just an early pass at this kind of empirically-anchored theoretical neurolingustics. Much more is yet to come. Even scientists should heed Wittgenstein's warning not to be too quick to formulate grand theories of language while so much data remains to be collected.

This is ambitious stuff. Deacon wants to explain the origins of language, underlying neural dynamics, explain symbolic reference and to show why Chomsky is wrong on his ideas on language. The result is a highly readable and complex text that somehow Deacon manages to maintain coherent. Many interesting ideas and insights can be found in the pages of this book. However it is not at all clear to me to what extent all of this is groundbreaking stuff. For example, darwinian processes in neural dynamics and development are not new ideas, as Deacon admits. Edelman, Calvin, Changeaux all got there first. The role Deacon gives to the prefrontal cortex is not new either. His explanation of symbolic reference as a collection of indexical and iconical relationships, and further symbo-symbolical higher orther relationships, is philosophically questionable to say the least. Why would symbolic abilities arise out of adding levels of non-symbolic relationships, in the way Deacon proposes?. Surely, symbolic abilities must depend on non symbolic mechanisms at some level, but it is not clear at which.

But Deacon also has moments of genius. His attack on Chomskian innate universal grammar frameworks is brilliant. Language evolved to adapt to the cognitive abilities of humans and therefore it seems it is learned too easilly. It is not that children have a grammar module, but that their general modules are enough when most of the adaptive work was done by language itself by evolving. Deacon also shows why grammars are not things that can become innate in the first place too. They cannot be invariant enough for selection to work on the brain to aquire them. Deacon also shows what did happen in the brain for there to be language. The relationship between brain-size and cognitive ability is more complex than we thought, and Deacon shows us why and how.
Also quite good is Deacons explanation of why language evolved in the first place. It evolved as a means to deal witht he changing social and sexual organization of hominid groups, that started to form pair-bonding while being foragers. Language acted as the glue that kept these dynamics stable.

This is very good stuff, and it is bold and plausible. Deacon did not solve the mystery of intentionality or language, but his insights might show the way towards doing exactly this. There are few other books on language and the brain as thought provoking as this one.

Reading only one or two pages into this book already makes it clear that this is a work by an exceptionally well informed and disciplined writer; and reading to the end does not disappoint at any time. This is a tightly argued serious scientific thesis by a professor of biological anthropology with an encyclopedic knowledge of linguistics, neurophysiology, neuroanatomy and human evolution. It is an original work in which Deacon sets out his arguments and marshals the evidence for a comprehensive theory in a methodical and structured way. It is not for the faint hearted, and reading it demands careful attention to the tightly written dense structured prose; it is not repetitive and the logical structure of the arguments is architectural, so that careful reading and a good memory are essential. Useful diagrammatic illustrations help to make some of the concepts easier to grasp. The effort is worth every moment. Deacon's conclusions have consequences for philosophy and theory of mind no less than for the central area of linguistics and the evolution of human intelligence. This book has done more to shape and to consolidate my knowledge of who we as a "symbolic species" are than any other I have read in this decade. Strongly recommended.

I edited THE SYMBOLIC SPECIES when I was employed atW. W. Norton, and no book I worked on in my fourteen years at Nortonever received so many enthusiastic comments and reviews from leading scholars in related fields. Prospective readers may like to know that cutting edge thinkers and researchers such as Merlin Donald, author of ORIGINS OF THE MODERN MIND, consider Terry Deacon's revolutionary exploration of human origins and consciousness to be "the best book yet written on the evolution of language" and "theoretical dynamamite planted deep under the walls of the neo-Chomskian fortress." Edward Manier, professor of philosophy at University of Notre Dame, says the book "should transform the foundations of the human sciences" and calls Deacon the "best neurophilosopher on the planet." Here are these and other leading scholars' advance reviews of THE SYMBOLIC SPECIES, along with excerpts from Booklist and the starred review in Library Journal.

"An extremely sophisticated analysis of the relationship between language and the brain. Deacon provides a compelling picture of how language evolved to fit the ape brain. He also explains why and how different languages may utilize different parts of the brain to carry out the same linguistic function." -- Patricia Greenfield, professor of psychology, UCLA

"A masterpiece. This superb and innovative look at the evolution of language could only have been written by the one person with the range, depth, and sheer competence to incorporate linguistics, ethology, developmental biology, paleontology, and evolutionary biology: Terry Deacon. An extraordinary achievement!" -- David Pilbeam, professor of anthropology, Harvard University

"This is an accessible yet erudite volume, witty and uncompromising. In my opinion it is the best book yet written on the evolution of language. Deacon has mounted a serious challenge to the neo-Chomskians. He has constructed a credible theory of language evolution that places grammar in a secondary role. The evolutionary action, says Deacon, is in the lexicon, and in the social nature of symbolic invention, rather than in grammar. Grammars emerge from the demands of the linguistic environment itself. Children learn grammar easily and fast, not because it is programmed into their genes, but because the language environment has its own built-in heuristic. This is theoretical dynamite, planted deep under the walls of the neo-Chomskian fortress.

"Deacon also has a great deal to say about how the human brain has adapted itself to deal with the challenge of symbolic reference, and especially on the complex relationships between brain growth, cognitive development, and social evolution. This is essential reading for anyone interested in what makes us human." -- Merlin Donald, professor of psychology, Queens University (Ontario and author of Origins of the Modern Mind

"If you have only one book to read on the evolution and function of the human brain, this is the one I would recommend." -- Jerome Kagan, Daniel and Amy Starch Professor of Psychology, Harvard University

"Terry Deacon's The Symbolic Species should transform the foundations of the human sciences.

"The book relocates the most significant puzzles of 'neurophilosophy$ in the context of the latest evolutionary models. These track the impact of a shift in social structures caused by the earliest forms of symbolic communication. The resulting selection pressures turn the brains of early humans in a direction counter-indicated by prevailing trends in mammalian and primate brain evolution.

"Deacon identifies substantial biological constraints on speculation about language acquisition devices, innate grammatical modules, the modularity of mind, and the language of thought. He stands conventional views on these topics on their heads. The bottleneck is not grammar, which can be simplified indefinitely. The real hurdle is reference: the yawning chasm on the rocky evolutionary-neurobiologicalreference: the yawning chasm on the rocky evolutionary-neurobiological road from icons and indices to symbols. No other account of the 'language instinct' covers these issues.

"Deacon offers fresh insight into philosophic controversies over eliminative materialism, 'the Chinese Room' and 'the Cartesian Theater,' and 'kinds of minds.' His discussion of levels of consciousness is remarkable for its lack of sectarian cant. His evolutionary naturalism escapes the old labels of reductionism, instrumentalism, and physicalism.

"Deacon combines the precision of a neurosurgeon with the rigor of a philosopher. He's my candidate for best neurophilosopher on the planet. His impressive command of comparative neuroscience, psycholinguistics, evolutionary theory and related disciplines makes this book indispensable for my courses in the philosophy of biology, philosophy of cognitive neuroscience, and philosophy, psychology and psychiatry. The Symbolic Species is not another grandiose lyric about the global properties of the brain. When this author finds 'nascent heart and mind' where most fear clockwork, he doesn't persuade his readers to believe; he shows them where to look." -- A. Edward Manier, professor of philosophy and of the history and philosophy of science, University of Notre Dame

"Terrence Deacon's book provides a remarkable and even-handed synthesis of knowledge obtained from a wide range of disciplines. THE SYMBOLIC SPECIES helps us understand why we are so remarkably different from other species in terms of learning the kinds of language systems that we do--and yet not all that different from the apes in terms of basic organization and function of our primate brain. THE SYMBOLIC SPECIES is written in a highly engaging style that permits us seemingly to hear the author's voice and to sense the spirit with which he so avidly pursued answers to questions of high interest to us all. THE SYMBOLIC SPECIES is an outstanding product of a gifted scholar. The book will be of great value to the curious lay reader as well as, of course, both to undergraduate and graduate courses." -- Duane M. Rumbaugh, professor of psychology, Georgia State University

"Both fascinating and accessible. In Deacon's exploration of human consciousness, the realms of neuroscience and evolutionary biology, among others, are within reach as Deacon >ponders how language came about, how the brains of Homo sapiens function, and why they are wired in ways that allow us to communicate by speaking." -- Booklist, July 1997

"Deacon challenges many of the ideas of Noam Chomsky and, more recently, Steven Pinker . . . [and] blends a knowledge of neurobiology, anthropology, linguistics, and philosophy into an original, well-argued, compelling theory of language development." -- Library Journal (starred review), June 15, 1997

Terrence Deacon has constructed a tome in which he unleashes his considerable learning in quest of several answers to the question, `What are we?' He is uniquely qualified to take an approach which details the origin and development of, first, language, then the brain, and, lastly, their `co-evolution.' Described on the jacket as `a world-renowned researcher in neuroscience and evolutionary anthropology,' all of his background is called upon at various times to pull together the mass of data and supposition that Deacon brings to the table.

In spite of the vastness of the territory he covers, Deacon's writing is most often accessible with a quiet wit which carries the reader along. This reviewer must confess, however, that he found the middle section on the evolution of the brain to be pretty dense traffic. Perhaps someone with a stronger neuroscientific background could follow Deacon into the intricacies of `using fly genes to make human brains.'

As the title indicates, Deacon attempts to show beyond much reasonable doubt that language does not `innately' exist in the brain like some sort of Chomskyian L.A.D. Instead he wishes to reveal that language itself has adapted to the brain over the years (much as we continue to adapt software programs for ease and complexity to computer hardwares). Over the millennia, language and brain have co-evolved, he reports, and thus there is no need to postulate a generative grammar or a single mother tongue from which all other languages emerged. He rests his case upon `Baldwinian evolution,' the theory of American psychologist Mark Baldwin from a century ago which suggests `that by temporarily adjusting behaviors or psychological responses during its lifespan in response to novel conditions, an animal could produce irreversible changes in the adaptive content of future generations' (pp. 322-323). Such changes over time lead to actual genetic changes.

We are, therefore, the symbolic species, the only one who crosses the `symbolic threshold' as a matter of course -- though Deacon does recognize that certain apes, chimps, and bonobo have been led across this threshold too. Borrowing from C. S. Peirce, Deacon understands that most species signal each other with iconic reference, a direct response to their environment. More advanced species learn to use indexical reference which indicates a class of potential references. With the development of actual language, we have crossed the symbolic threshold so our symbolic reference is most often to other symbols (each of which is indexically constructed). We take up residence in a `virtual' world with senses of time, space, and personhood unknown to other animals.

These ideas will sound extreme to some but his patiently detailed exposition is generally quite convincing. He steps out into pure speculation when he suggests that the marriage contract was likely the origin of symbolic reference. (How else could mates mark their territory when one hunts and one gathers?)

He doesn't address consciousness, itself, until page 438, where he follows the Peircean referencing system -- iconic, indexical, symbolic-to speak of levels of consciousness, `yet few would be willing to say that the consciousness of a dog or cat is of the same sort that we ascribe to humans' (p. 439). When trying to determine whether or not simpler information processing animals can be said to be conscious, he throws up his hands and declares, `What a complicated mess!' (p. 441). Yet he eventually argues that only symbolic consciousness allows for a sense of selfhood and intersubjectivity: `Its virtual nature notwithstanding, it is the symbolic realm of consciousness that we most identify with and from which our sense of agency and self-control originate' (p. 452). This throws into doubt just what sort of consciousness he is attributing to instinct-bounded nervous systems of iconic reference. Without agency or selfhood, can a creature be fairly thought to be conscious when terms like non-conscious experiencing would do?

He seems to understand the degrees of complexity as being fundamentally computational. This being the case, no one should be surprised when he predicts toward the end of his long book that computers will someday be capable of symbolic reference -- but first they must attain sentience so as to become capable of self evolution. Not an easy request! If and when this does occur, `[t]he question before us is whether we will begin to treat people like unconscious computers, or come to treat conscious computers like people' (p. 464). A rather jarring note on which to close, I thought, especially for a book which focuses mainly on human mentality and the symbolic reference of language.

Professor Deacon's analysis and discussion of the the evolution of the human brain is a wonderful achievement. He applies his unique combination of expertise in evolutionary theory and neurobiology to present a thoroughly convincing and concise picture of how this important human trait evolved. It will be a cornerstone of human evolutionary neurobiology for years come and is currently recommended reading in the doctoral program in biological anthropology at Yale University.

This review was published in Bostonia, Spring 1998, Number 1, 72-73,

Imagine a mutant being, genetically gifted to paint like Vermeer, born

into a culture where no one else can even doodle with a stick. That is

the classic Chomskyan view of the origin of language: by genetic

accident, astounding special language abilities were inserted into the

human brain. In The Symbolic Species, Terrence Deacon, professor of

anthropology at Boston University, offers an alternative picture.

Language, he argues, is not an instinct and there is no genetically

installed linguistic black box in our brains. Language arose slowly

through cognitive and cultural inventiveness. Two million years ago,

australopithecines, equipped with nonlinguistic ape-like mental

abilities, struggled to assemble, by fits and starts, an extremely crude

symbolic system - fragile, difficult to learn, inefficient, slow, <! P>inflexible, and tied to ritual representation of social contracts like

marriage. We would not have recognized it as language.

Language then improved by two means. First, invented linguistic forms

were subjected to a long process of selection. Generation after

generation, the newborn brain deflected linguistic inventions it found

uncongenial. The guessing abilities and intricate nonlinguistic biases

of the newborn brain acted as filters on the products of linguistic

invention. Today's languages are systems of linguistic forms that have

survived. The child's mind does not embody innate language structures.

Rather, language has come to embody the predispositions of the child's

mind.

This view reminds me of something Paul Valéry said in The Art of Poetry:

"Poetry can be recognized by its ability to get us to reproduce it in

its own form: it stimulates us to reconstruct it identically." Poetry so

thoroughly harmonizes with the p! redispositions of the human brain that

it flows into the! brain and occupies it, sowing there the seed of its

own replication. In Deacon's view, language has evolved to become poetry

for the newborn brain.

The second, subordinate means by which language improved, in Deacon's

view, had to do with changes in the brain. Crude and difficult language

imposed the persistent cognitive burden of erecting and maintaining a

relational network of symbols. In that demanding environment, genetic

variations that rendered brains more adept at language were favored.

Language began as a cognitive adaptation. Genetic assimilation then

eased some of the burden. Cognitive effort and genetic assimilation

interacted as language and brain co-evolved.

The notion that a magical genetic black box for language was inserted

into brains otherwise essentially like our own has become the mainstream

view, but it was originally an afterthought on the part of Chomskyan

grammarians who were primarily interested in analyzing t! he formal

structures of language as we know it. Chomsky acknowledges the

tenuousness of the evidence for speculating about the origin of

language. "You can," he says in lectures, "tell any story you like."

Actually, he shows special dislike for some stories, including the

proposal (by, for example, Stephen Pinker and Paul Bloom) that language

originated by natural selection on initial genetic variation. Elsewhere,

I have argued that Pinker and Bloom's genes-first adaptationist account

is weak because it does not offer a plausible "environment of

evolutionary adaptation" for language, that is, an environment in which

the first lone genetically grammatical person would have enjoyed

reproductive advantage.

The most obvious environment in which genetic endowments useful for

language would have been favored is a community of people whose members

had already invented rudimentary language by drawing on their

p! re-existing cognitive abilities, the crucial one being, in ! my view,

"parable" - the conceptual projection of small stories. Rudimentary

grammatical categories (like "verb") arose by projection from basic

elements of stories (like "action").

Pinker and Bloom cannot propose that language is a cognitive invention

that underwent genetic assimilation (they do see a place for genetic

assimilation once normal hearers began striving to comprehend the

dazzling linguistic productions of genetically blessed speakers) because

they think genetic specialization for language must have begun the

process ("There must have been a series of steps leading from no

language at all to language as we now find it, each step small enough to

have been produced by a random mutation or recombination"). Against the

Vermeer-from-a-magic-hat grammarians and against the genes-first

adaptationists, Deacon argues that language was a cognitive and cultural

invention that underwent genetic ! assimilation. He adduces a wealth of

anthropological, paleontological, and neurobiological evidence.

Language, he argues, was "acquired with the aid of flexible ape-learning

abilities." It was grafted onto an apelike brain. It is not walled off

from other cognitive functions such as interpreting and reasoning.

Grammatical form is not independent of conceptual meaning. There is no

linguistic black box and there was no insertion.

Genetic assimilation (known as "Baldwinian evolution") could not, Deacon

argues, put patterns of universal grammar into brains. To be subject to

natural selection, basic grammatical operations would have to be

realized invariantly in neural circuitry across the entire human

population, but they are not. "Those aspects of language that many

linguists would rank most likely to be part of a Universal Grammar are

precisely those that are ineligible to participate in Baldwinian

evolution! If ! there are innate rules of grammar in the minds of human

! infants, then they could not have gotten there by genetic assimilation,

only by miraculous accident." Instead, genetic assimilation built new

wetware, largely in the area of prefrontal cortex, that assisted

attention, memory, and association, consequently easing the burden of

language. These neurobiological changes were "a direct consequence of

the use of words. . . . [T]he major structural and functional

innovations that make human brains capable of unprecedented mental feats

evolved in response to the use of something as abstract and virtual as

the power of words." "An idea," says Deacon, "changed the brain."

The Symbolic Species is a dose of vitamin C for a field with a chronic

head cold. Theoretical linguistics, as a scientific enterprise, is

locked into an unfortunate pattern in which theory and evidence define

each other so thoroughly that opposing camps feel comfortable dismissing

rather than conf! ronting one another. Two linguists of the greatest

eminence and learning can disagree about fundamental questions (does

syntax depend on meaning?) without submitting to a generally respected

method for deciding which, if either, of them is right. The best hope

for springing linguistics from this disciplinary bind lies in bringing

to bear other human sciences like anthropology, cognitive science, and

neuroscience. Deacon leads the way.

Human language is a subject of great interest to everyone, but knowing its origin and biological framework is almost intractable owing mainly to the fact that there is only one living species with this unique human trait. (Ideally, we would compare many species with different "versions" of a given trait in order to learn something about how it arises and what it is for.) Also, there is a difficulty whenever humans try to study themselves, and a tendency to interpret the beginnings and evolution of a human feature directly in the context of the modern world. For example, language is used today for many things, but which, if any, of these uses relates to its initial development and subsequent evolution? During the last century, the brilliant philosopher Charles Sanders Peirce developed a theory of thought that was internally compelling and logical, but (unfortunately) difficult to understand and somewhat obscured by a great deal of digression and possibly unnecessary complexity in presentation. Within the last century, a tremendous amount of evidence for the nitty gritty details of the evolution of our species, in the form of fossils and archaeological material, has been unearthed. During recent decades, great strides have been made in the fields of primate cognition (for example, language studies of apes like Washoe and Kanzi) and the neurology of the human brain. "The Symbolic Species" is the first work that I have read that integrates this vast array of evidence into a useful description and probable theory of human language evolution and functioning. Deacon steps clear of the usual "human" biases by re-asking, on entirely new and creative terms, the basic questions of human language function and evolution. He explains clearly CS. Peirce's logic, and develops from this (and other sources, including his own pathbreaking work) a model for human symbolic thought. Deacon does an outstanding job of making sense of the neuroscience and primate cognitive studies, fairly evaluating claims made in those fields, explaining them clearly, and conferring on the careful reader an expertise in these disciplines. Deacon's model for human language evolution and functioning is not merely presented as an alternative to other ideas or an addition to prior scholarly work. Rather, Deacon effectively (but politely) destroys much of the prevailing theory, but with due consideration and preservation of that which is most likely right in recent scholarship. It is not possible to intelligently read Deacon's book and still accept a Chomskian view of human language. Deacon's conclusions conflict directly with much of the (also brilliant) work by Stephen Pinker (i.e., "The Language Instinct"). Until the publication of this book, we can assume that Terrance Deacon understood human language evolution better than any other scholar. Now, with its publication, this important knowledge is more widely available. "The Symbolic Species" is not exactly light reading, but it is very accessible. Prior knowledge of this field is not necessary to fully understand Deacon's engaging presentation. "The Symbolic Species" is richly illustrated with Deacon's own visuals, which present data and models in ways that are really worth thousands of words.

As someone with a strong interest in neuroscience (PhD in experimental psychology, about 10 years doing brain and spinal cord research) I was initially very enthusiastic about this book. As I went along, though, I began to develop a real discomfort about the way the material was presented. And, after making two really strong attempts, I just could not finish (something that I almost never do). Although I had many problems with the book, the most important were the poor separation of authorial speculation from known facts of neurology, making it difficult to tell what is empirically supported and what is simply appealing to the author on deductive principles (and deductive principles work overtime in this book); "resolution" of false controversies (e.g., the author spends about 50 pages "refuting" the "hypothesis" that intelligence is related to brain size in a simple linear fashion, a view that is probably not held by any neuroscience researcher anywhere); and many leaps of logic and inferences that, although they sound like really cool ideas, just do not appear to be supported by any evidence at all. Phrases like "there is probably no invariant feature," or "are likely to be functionally interconnected" or "may provide a substrate for..." appear on almost every page, usually without notes.

There are also serious editorial problems with the book. I don't want to make too much of it, because I would certainly be willing to put up with poor editing to read something interesting. But the editorial quality is extremely poor. There are subject-verb mismatches, sentence fragments or run-ons, author names spelled two different ways in citations, terms used for 20 pages and then suddenly defined, and so on. Many parts read like sections of a hastily prepared rough draft.

I could have written a much, much longer review of many specific problems that I had with this book, but I'm trying to keep this short. Altogether I found this to be a huge disappointment (possibly the most disappointing non-fiction book I have ever read) although I note that there are plenty of reviews below from people who seem to have enjoyed it.

This book contains several tremendous leaps of understanding which people are going to be assimilating for the next few decades. "Leap of understanding" meaning the sort of fundamental insight achieved by Newton, Darwin, and Einstein. I think Deacon's great leaps are going to stand the test of time. What are they? Well, here are some...

(1) What is the difference between humans and all the other animals? The ability to process symbolic references. This is an extremely technical reply, and is fully explained in the book. Deacon has put his finger on a fine answer to a question which has perplexed us forever.

(2) When did language start evolving? Probably at the same time humans began splitting off from the other monkeys, at the same time we developed primitive stone tools. Or, say, 2 million years ago. NOT 40,000 years ago.

(3) Do other animals have language? See the book for the exact answer. In brief, no. Other animals have systems of communication but they do not have symbolic reference, the basis of the language which defines our species.

(4) How old is marriage? Deacon guesses that marriage was one of the very first practical uses of symbolic reference. This guess is extremely thought-provoking!

Deacon agrees with the author of "The Lives of a Cell" (Lewis Thomas) that language is a "hive product" and offers a number of startling insights which make the point quite obvious. Unlike some trendy cognitive scientists, Deacon takes consciousness as a given, a fundamental, and builds from there.

Very interesting companion reading: John Searle's "The Construction of Social Reality." Philosophy and science reaching the same conclusions.