George LAKOFF / Mark JOHNSON
PHILOSOPHY IN THE FLESH
The Embodied Mind and its Challenge to Western Thought
Perseus Books 1999
Introduction: Who Are We?
How Cognitive Science Reopens Central Philosophical Questions
The Mind is inherently embodied.
Thought is mostly unconscious.
Abstract concepts are largely metaphorical.
These are three major findings of cognitive science. More than two millennia of a priori philosophical speculation about these aspects of reason are over. Because of these discoveries, philosophy can never be the same again.
When taken together and considered in detail, these three findings from science of the mind are inconsistent with central parts of Western philosoph They require a thorough rethinking of the most popular current approache namely, Anglo-American analytic philosophy and postmodernist philosophy.
This book asks: What would happen if we started wieh these empirical di coveries about the nature of mind and constructed philosophy anew? The answer is that an empirically responsible philosophy would require our culture to abandon some of its deepest philosophical assumptions. This book is an exte' sive study of what many of those changes would be in detail.
Our understanding of what the mind is matters deeply. Our most basic philosophical beliefs are tied inextricably to our view of reason. Reason has been taken for over two millennia as the defining characteristic of human beings. Reason includes not only our capacity for logical inference, but also our ability to conduct inquiry, to solve problems, to evaluate, to criticize, to deliberate about how we should act, and to reach an understanding of ourselves, other people, and the world.
A radical change in our understanding of reason is therefore a radical change in our understanding of ourselves. It is surprising to discover, on the basis of empirical research, that human rationality is not at all what the West-ern philosophical tradition has held it to be. But it is shocking to discover that we are very different from what our philosophical tradition has told us we are.
Let us start with the changes in our understanding of reason:
o Reason is not disembodied, as the tradition has largely held, but arises from the nature of our brains, bodies, and bodily experience. This is not just the innocuous and obvious claim that we need a body to reason; rather, it is the striking claim that the very structure of reason itself comes from the details of our embodiment. The same neural and cogni-tive mechanisms that allow us to perceive and move around also create our conceptual systems and modes of reason. Thus, to understand rea-son we must understand the details of our visnal system, our motor sys-tem, and the general mechanisms of neural binding. In summary, reason is not, in any way, a transcendent feature of the universe or of disem-bodied mind. Instead, it is shaped crucially by the peculiarities of our human bodies, by the remarkable details of the neural structure of our brains, and by the specifics of our everyday functioning in the world.
o Reason is evolutionary, in that abstract reason builds on and makes use of forms of perceptual and motor inference present in "lower" animals. The result is a Darwinism of reason, a rational Darwinism: Reason, even in its most abstract form, makes use of, rather than transcends, our animal nature. The discovery that reason is evolutionary utterly changes our relation to other animals and changes our conception of human beings as uniquely rational. Reason is thus not an essence that separates us from other animals; rather, it places us on a continuum with them.
o Reason is not "universal" in the transcendent sense; that is, it is not part of the structure of the universe. It is universal, however, in that it is a capacity shared universally by all human beings. What allows it to be shared are the commonalities that exist in the way our minds are em-bodied.
o Reason is not completely conscious, but mostly unconscious.
o Reason is not purely literal, but largely metaphorical and imaginative.
o Reason is not dispassionate, but emotionally engaged.
This shift in our understanding of reason is of vast proportions, and it entails a corresponding shift in our understanding of what we are as human beings. What we now know about the mind is radically at odds with the major classical philosophical views of what a person is.
For example, there is no Cartesian dualistic person, with a mind separate
from and independent of the body, sharing exactly the same disembodied tran-scendent reason with everyone else, and capable of knowing everything about his or her mind simply by self-reflection.
Rather, the mind is inherently embod-ied, reason is shaped by the body, and since most thought is unconscious, the mind cannot be known simply by self-reflection. Empirical study is necessary.
There exists no Kantian radically autonomous person, with absolute free-
dom and a transcendent reason that correctly dictates what is and isn't moral. Reason, arising from the body, doesn't transcend the body. What universal as-pects of reason there are arise from the commonalities of our bodies and brains and the environments we inhabit. The existence of these universals does not imply that reason transcends the body. Moreover, since conceptual systems vary significantly, reason is not entirely universal.
Since reason is shaped by the body, it is not radically free, because the possi-ble human conceptual systems and the possible forms of reason are limited. In addition, once we have learned a conceptual system, it is neurally instantiated in our brains and we are not free to think just anything. Hence, we have no ab-solute freedom in Kant's sense, no full autonomy. There is no a priori, purely philosophical basis for a universal concept of morality and no transcendent, universal pure reason that could give rise to universal moral laws.
The utilitarian person, for whom rationality is economic rationalitythe maximization of utilitydoes not exist. Real human beings are not, for the most part, in conscious control ofor even consciously aware oftheir reasoning. Most of their reason, besides, is based on various kinds of prototypes, framings, and metaphors. People seldom engage in a form of economic reason that could maximize utility.
The phenomenological person, who through phenomenological introspection i alone can discover everything there is to know about the mind and the nature of experience, is a fiction. Althongh we can have a theory of a vast, rapidly and au-tomatically operating cognitive unconscious, we have no direct conscious access to its operation and therefore to most of our thonght. Phenomenological reflec-tion, though valuable in revealing the structure of experience, must be supple-mented by empirical research into the cognitive unconscious.
There is no poststructuralist personno completely decentered subiect for whom all meaning is arbitrary, totally relative, and purelv historically contingent, unconstrained by body and brain. The mind is not merely embodied, but | embodied in such a way that our conceptual systems draw largely upon the commonalities of our bodies and of the environments we live in. The result is i that much of a person's conceptual system is either universal or widespread across languages and cultures. Our conceptual systems are not totally relative and not merely a matter of historical contingency, even though a degree of con- e ceptual relativir' does exist and even though historical contingency does mat-ter a great deal. The grounding of our conceptual systems in shared embodiment and bodily experience creates a largely centered self, but not a monolithic self.
There exists no Fregean personas posed by analytic philosophyfor' whom thought has been extruded from the body. That is, there is no real person whose embodiment plays no role in meaning, whose meaning is purely objective and defined by the external world, and whose language can fit the i external world with no significant role played by mind, brain, or body. Because our conceptual systems grow out of our bodies, meaning is grounded in and throngh our bodies. Because a vast range of our concepts are metaphorical, e meaning is not entirely literal and the classical correspondence theory of truth is false. The correspondence theory holds that statements are true or false ob-jectively, depending on how they map directly onto the worldindependent of any humar; understanding of either the statement or the world. On the contrary, truth is mediated by embodied understanding'and imagination. That does not mean that truth is purely subjective or that there is no stable truth. Rather, our common embodiment allows for common, stable truths.
There is no such thing as a computational person, whose mind is like computer software, able to work on any suitable computer or neural hardware whose mind somehow derives meaning from taking meaningless symbols as-input, manipulating them by role, and giving meaningless symbols as output. e Real people have embodied minds whose conceptual systems arise from, are shaped by, and are given meaning through living human bodies. The neural structures of our brains prodace conceptual systems and linguistic structures that cannot be adequately accounted for by formal systems that only manipulate symbols.
Finally, there is no Chomskyan person, for whom language is pure syntax, | pure form insulated from and independent of all meaning, context, perception, ~ emotion, memory, attention, action, and the dynamic nature of communication. Moreover, human language is not a totally generic innovation. Rather, central aspects of language arise evolutionarily fr'om sensory, motor, and other neural systems that are present in "lower" animals.
Classical philosophical conceptions of the person have stirred our imagina-tions and taught us a great deal. But once we understand the importance of the cognitive unconscious, the embodiment of mind, and metaphorical thonght, we can never go back to a priori philosophizing about mind and language or to philosophical ideas of what a person is that are inconsistent with what we are learning about the mind.
Given our new understanding of the mind, the question of what a human be-ing is arises for us anew in the most urgent way.
Asking Philosophical Questions Requires Using Human Reason
If we are going to ask philosophical questions, we have to remember that we are human. As human beings, we have no special access to any form of purely objective or transcendent reason. We must necessarily use common human cognitive and neural mechanisms. Because most of our thought is unconscious, a priori philosophizing provides no privileged direct access to knowledge of our own mind and how our experience is constituted.
In asking philosophical questions, we use a reason shaped by the body, a cognitive unconscious to which we have no direct access, and metaphorical thonght of which we are largely unaware. The fact that abstract thought is mostly metaphorical means that answers to philosophical questions have al-ways been, and always will be, mostly metaphorical. In itself, that is neither good nor bad. It is simply a fact about the capacities of the human mind. But it has malor consequences for every aspect of philosophy. Metaphorical thought is the principal tool that makes philosophical insight possible and that con-strains the forms that philosophy can take.
Philosophical reflection, uninformed by cognitive science, did not discover, establish, and investigate the details of the fundamental aspects of mind we will be discussing. Some insightful philosophers did notice some of these phe-nomena, but lacked the empirical methodology to establish the validity of these results and to study them in fine detail. Without empirical confirmation, these facts about the mind did not find their way into the philosophical main-stream.
Jointly, the cognitive unconscious, the embodiment of mind, and metaphorical thought require not only a new way of understanding reason and the nature of a person. They also require a new understanding of one of the mos common and natural of human activitiesasking chilosoDhical cuestions.
What Goes into Asking and Answering Philosophical Questions?
If you're going to reopen basic philosophical issues, here's the minimum you have to do. First, you need a method of investigation. Second, you have to use that method to understand basic philosophical concepts. Third, you have to apply that method to previous philosophies to understand what they are about and what makes them hang together. And fourth, you have to use that method to ask the big questions: What it is to be a person? What is morality? How do we understand the causal structure of the universe? And so on.
This book takes a small first step in each of these areas, with the intent of giving an overview of the enterprise of rethinking what philosophy can become. The methods we use come from cognitive science and cognitive linguis-tics. We discuss these methods in Part I of the book.
In Part II, we study the cognitive science of basic philosophical ideas. That is, we use these methods to analyze certain basic concepts that any approach to philosophy must address, such as time, events, causation, the mind, the self, and morality.
In Part III, we begin the study of philosophy itself from the perspective of cognitive science. We apply these analytic methods to important moments in the history of philosophy: Greek metaphysics, including the pre-Socratics, Plato, and Aristotle; Descartes's theory of mind and Enlightenment faculty psy-chology; Kant's moral theory; and analytic philosophy. These methods, we ar-gue, lead to new and deep insights into these great intellectual edifices. They help us understand those philosophies and explain why, despite their funda-mental differences, they have each seemed intuitive to many people over the centuries. We also take up issues in contemporary philosophy, linguistics, and the social sciences, in particular, Anglo-American analytic philosophy, Chom-skyan linguistics, and the rational-actor model used in economics and foreign policy. :
Finally, in Part IV, we summarize what we have learned in the course of this inquiry about v hat human beings are and about the human condition.
What emerges is a philosophy close to the bone. A philosophical perspective based on our empirical understanding of the embodiment of mind is a philoso-phy in the flesh, a philosophy that takes account of what we most basically are and can be.
The Cognitive Unconscious
Living a human life is a philosophical endeavor. Every thought we have, every decision we make, and every act we perform is based upon philosophical assumptions so numerous we couldn't possibly list them all.
We go around armed with a host of presuppositions about what is real, wha counts as knowledge, how the mind works, who we are, and how we should act. Such questions, which arise out of our daily concerns, form the basic sub-ject matter of philosophy: metaphysics, epistemology, philosophy of mind ethics, and so on.
Metaphysics, for example, is a fancy name for our concern with what is real Traditional metaphysics asks questions that sound esoteric: What is essence? What is causation? What is time? What is the self? But in everyday terms there is nothing esoteric about such questions.
Take our concern with morality. Does morality consist of a set of absolut moral laws that come from universal reason? Or is it a cultural construct? O neither? Are there unchanging universal moral values? Where does morality come from? Is it part of the essence of what it is to be a human being? Is therc an essence of what it is to be a human being? And what, exactly, is an essence anyway?
Causation might appear to be another esoteric topic that only a philosophe could care about. But our moral and political commitments and actions pre suppose implicit views on whether there are social causes and, if so, what the, might be. Whenever we attriLute moral or social responsiLility, we are implic itly assuming the possibility of causation, as well as very specific notions of what a cause is.
Or take the self. Asking about the nature of the self might seem to be the ultimate in esoteric metaphysical speculation. But we cannot get through a day without relying on unconscious conceptions of the internal structure of the self. Have you taken a good look at yourself recently? Are you trying to find your "trne self"? Are you in control of yourself? Do you have a hidden self that you are trying to protect or that is so awful you don't want anyone to know about it? If you have ever considered any matters of this sort, you have been relying on unconscious models of what a self is, and you could hardly live a life of any introspection at all without doing so.
Though we are only occasionally aware of it, we are all metaphysicians not in some ivory-tower sense but as part of our everyday capacity to make sense of our experience. It is through our conceptual systems that we are able to make sense of everyday life, and our everyday metaphysics is embodied in those conceptual systems.
THE COGNITIVE UNCONSCIOUS
Cognitive science is the scientific discipline that studies conceptual systems. It is a relatively new discipline, having been founded in the 1970s. Yet in a short time it has made startling discoveries. It has discovered, first of all, that most of our thought is unconscious; not in the Freudian sense of being repressed, but in the sense that it operates beneath the level of cognitive awareness, inaccessible to consciousness and operating too quickly to be focused on.
Consider, for example, all that is going on below the level of conscious awareness when you are in a conversation. Here is only a small part of what you are doing, second by second:
Accessing memories relevant to what is being said
Comprehending a stream of sound as being language, dividing it into distinctive phonetic features and segments, identifying phonemes, and grouping them into morphemes
Assigning a structure to the sentence in accord with the vast number of grammatical constructions in your native language
Picking out words and giving them meanings~appropriate to context.
Making semantic and pragmatic sense of the sentences as a whole
Framing what is said in terms relevant to the discussion
Performing inferences relevant to what is being discussed
Constructing mental images where relevant and inspecting them
Filling in gaps in the discourse Noticing and interpreting your interlocutor's body language
Anticipating where the conversation is going Planning what to say in response
Cognitive scientists have shown experimentally that to understand even the simplest utterance, we must perform these and other incredibly complex forms of thonght automatically and without noticeable effort below the level of con-sciousness. It is not merely that we occasionally do not notice these processes; rather, they are inaccessible to conscious awareness and control.
When we understand all that constitutes the cognitive unconscious, our understanding of the nature of consciousness is vastly enlarged. Consciousness goes way beyond mere awareness of something, beyond the mere experience of qualia (the qualitative senses of, for example, pain or color), beyond the awareness that you are aware, and beyond the multiple takes on immediate ex-perience provided by various centers of the brain. Consciousness certainly in-volves all of the above plus the immeasurably vaster constitutive framework provided by the cognitive unconscious, which must be operating for us to be aware of anything at all.
Why "Cognitive" Unconscious?
The term cognitive has two very different meanings, which can sometimes cre-ate confusion. In cognitive science, the term cognitive is used for any kind of mental operation or structure that can be studied in precise terms. Most of these structures and operations have been found to be unconscious. Thus, vi-sual processing falls under the cognitive, as does auditory processing. Obvi-ously, neither of these is conscious, since we are not and could not possibly be aware of each of the neural processes involved in the vastly complicated total process that gives rise to conscious visual and auditory experience. Memory and attention fall under the cognitive. All aspects of thonght and language, conscious or unconscious, are thus cognitive. This inclndes phonology, gram-mar, conceptual systems, the mental lexicon, and all unconscious inferences of any sort. Mental imagery, emotions, and the conception of motor operations have also been studied from such a cognitive perspective. And neural modeling of any cognitive operation is also part of cognitive science.
Confusion sometimes arises because the term cognitive is often used in a very different way in certain philosophical traditions. For philosophers in these tra-ditions, cogr~itive means only conceptual or propositional structure. It also in-clndes rule-governed operations on such conceptual and propositional structures. Moreover, cognitive meaning is seen as truth-conditional meaning, that is, meaning defined not internally in the mind or body, but by reference to things in the external world. Most of what we will be calling the cognitive un-conscious is thus for many philosophers not considered cognitive at all.
As is the practice in cognitive science, we will use the term cognitive in the richest possible sense, to describe any mental operations and structures that are involved in language, meaning, perception, conceptual systems, and reason. Because our conceptual systems and our reason arise from our bodies, we will also use the term cognitive for aspects of our sensorimotor system that con-triLute to our abilities to conceptualize and to reason. Since cognitive opera-tions are largely unconscious, the term cognitive unconscious accurately describes all unconscious mental operations concerned with conceptual sys-tems, meaning, inference, and language.
The Hidden Hand That Shapes Conscious Thought
The very existence of the cognitive unconscious, a fact fundamental to all con-ceptions of cognitive science, has important implications for the practice of philosophy. It means that we can have no direct conscious awareness of most of what goes on in our minds. The idea that pure philosophical reflection can plumb the depths of human understanding is an illusion. Traditional methods of philosophical analysis alone, even phenomenological introspection, cannot come close to allowing us to know our own minds.
There is much to be said for traditional philosophical reflection and phenomenological analysis. They can make us aware of many aspects of consciousness and, to a limited extent, can enlarge our capacities for conscious awareness. Phenomenological reflection even allows us to examine many of the background prereflective structures that lie beneath our conscious experience. But neither method can adequately explore the cognitive unconsciousthe realm of thonght that is completely and irrev~cably inaccessible to direct con-scious introspection. It is this realm that is the primary focas of cognitive sci-ence, which allo~vs us to theorize about the cognitive unconscious on the basis of evidence. Cognitive science, however, does not allow us direct access to what the cognitive unconscious is doing as it is doing it.
Conscious thought is the tip of an enormous iceberg. It is the rule of thumb among cognitive scientists that unconscious thought is 95 percent of all thonghtand that may be a serious underestimate. Moreover, the 95 percent below the surface of conscious awareness shapes and structures all conscious thonght. If the cognitive unconscious were not there doing this shaping, there could be no conscious thought.
The cognitive unconscious is vast and intricately structured. It includes not only all our automatic cognitive operations, bot also all our implicit knowledge. All of our knowledge and beliefs are framed in terms of a conceptual sys-tem that resides mostly in the cognitive unconscious.
Our unconscious conceptual system functions like a "hidden hand" that shapes how we conceptualize all aspects of our experience. This hidden hand gives form to the metaphysics that is bnilt into our ordinary conceptual sys-tems. It creates the entities that inhabit the cognitive unconsciousabstract en-tities like friendships, bargains, failures, and liesthat we use in ordinary unconscious reasoning. It thus shapes how we automatically and uncon-sciously comprehend what we experience. It constitutes our unreflective com-mon sense. ~
For example, let us return to our commonsense understanding of the self. Consider the common experience of struggling to gain control over ourselves. We not only feel this struggle within us, but conceptualize the "struggle» as be-ing between two distinct parts of our self, each with different values. Some-times we think of our "higher» (moral and rational) self struggling to get control over our «lower» (irrational and amoral) self.
Our conception of the self, in such cases, is fundamentally metaphoric. We conceptualize ourselves as split into two distinct entities that can be at war, locked in a struggle for control over our bodily behsvior. This metaphoric con-ception is rooted deep in our unconscious conceptual systems, so much so that it takes considerable effort and insight to see how it functions as the basis for reasoning about ourselves.
Similarly, when you try to find your "true self," you are using another, usu-ally unconscious metaphorical conceptualization. There are more than a dozen such metaphorical conceptions of the self, and we will discuss them below. When we consciously reason about how to gain mastery over ourselves, or how to nrotect our vulnerable "inner self." or how to find our "true self," it is the hidden hand of the unconscious conceptual system that makes such reasoning "common sense."
Metaphysics as Metaphor
A large part of this book will be devoted to exploring in detail what the hidder hand of our unconscious conceptual system looks like and how it shapes no only everyday commonsense reasoning but also philosophy itself. We will dis cuss some of the most basic of philosophical concepts, not only the self bu also time, events, causation, essence, the mind, and morality. What is startling is that, even for these most basic of concepts, the hidden hand of the uncon scious mind uses metaphor to define our unconscious metaphysicsthe meta physics used not just by ordinary people, but also by philosophers to make sense of these concepts. As we will see, what counts as an "intuitive" philo sophical theory is one that draws upon these unconscious metaphors. In short philosophical theories are largely the product of the hidden hand of the cognitive unconscious.
Throughout history it has been virtually impossible for philosophers to dc metaphysics without such metaphors. For the most part, philosophers engagec in making metaphysical claims are choosing from the cognitive unconscious a set of existing metaphors that have a consistent ontology. That is, using uncon scious everyday metaphors, philosophers seek to make a noncontradictor) choice of conceptual entities defined by those metaphors; they then take those entities to be real and systematically draw out the implications of that choice ir an attempt to account for our experience using that metaphysics.
Metaphysics in philosophy is, of course, supposed to characterize what is realliterally real. The irony is that such a conception of the real depend upon unconscious metaphors.
Empirically Responsible Philosophy: Beyond Naturalized Epistemoloy
For more than two thousand years, philosophy has defined metaphysics as the study of what is literally real. The weight of that tradition is so great that it is hardly likely to change in the face of empirical evidence against the tradition it self. Nevertheless that evidence, which comes from cognitive science, exists and raises deep questions not only about the project of philosophical metaphysics but also about the nature of philosophy itself.
Throughout most of our history, philosophy has seen itself as being indepen-dent of empirical investigation. It is that aspect of philosophy that is called into question by results in cognitive science. Through the study of the cognitive un-conscious, cognitive science has given us a radically new view of how we con-ceptualize our experience and how we think.
Cognitive sciencc the empirical study of the mindcalls upon us to create a new, empirically responsible philosophy, a philosophy consistent with empir-ical discoveries about the nature of mind. This is not just old-fashioned philos-ophy "naturalized"making minor adlustments, bot basically keeping the old philosophical superstructure.
A serious appreciation of cognitive science requires us to rethink philosophy from the beginning, in a way that would put it more in touch with the reality of how we think. It would be based on a detailed understanding of the cogni-tive unconscious, the hidden hand that shapes our conscious thought, our moral values, our plans, and our actions.
Unless we know our cognitive unconscious fnlly and intimately, we can neither know ourselves nor truly understand the basis of our moral judgments, our conscious deliberations, and our philosophy.
Chapter 3 pg.16
The Embodied Mind
What does it mean to say that concepts and reason are embodied? This chapter takes a first step toward answering that question. It takes up the role that the perceptual and motor systems play in shaping particalar kinds of concepts: color concepts, basic-level concepts, spatial-relations concepts, and aspectual (event-structuring) concepts.
Any reasoning yöu do using a concept requires that the neural structures of the brain carry out that reasoning. Accordingly, the architecture of your brain's neural networks determines whae concepts you have and hence the kind of reasoning you can do. Neural modeling is the field that studies which configurations of neu-rons carry out the neural computations that we experience as particular forms of rational thonght. It also studies how such neural configurations are learned.
Neural modeling can show in detail one aspect of what it means for the mind to be embodied. how particular configurations of neurons, operating accord-ing to principles of neural computation, compute what we experience as ratio-nal inferences. At this point the vague question "Can reason make use of the sensorimotor system?" becomes the technically answerable question "Can ra-tional inferences be computed by the same neural architecture used in percep-tion or bodily movement?" We now know that, in some cases, the answer to this question is yes. Those cases will be discussed in this chapter.
How the Body and Brain Shape Reason
We have inherited from the Western philosophical tradition a theory of faculty psychology, in which we have a «faculty» of reason that is separate from and in-dependent of what we do with our bodies. In particular, reason is seen as inde-pendent of perception and bodily movement. In the Western tradition, this au-tonomous capacity of reason is regarded as what makes us essentially human, distinguishing us from all other animals. If reason were not autonomous, that is, not independent of perception, motion, emotion, and other bodily capacities, then the philosophical demarcation between us and all other animals would be less clearly drawn. This view was formulated prior to the emergence of evolution-ary theory, which shows that human capacities grow out of animal capacities.
The evidence from cognitive science shows that classical faculty psychology is wrong. There is no such fully autonomous faculty of reason separate from and independent of bodily capacities such as perception and movement. The evidence supports, instead, an evolutionary view, in which reason uses and grows out of such bodily capacities. The result is a radically different view of what reason is and therefore of what a human being is. This chapter surveys some of the evidence for the view that reason is fundamentally embodied.
These findings of cognitive science are profoundly disquieting in two respects. First, they tell us that
human reason is a form of animal reason, a rea-son inextricably tied to our bodies and the peculiarities of our brains. Second, these results tell us that our bodies, brains, and interactions with our environ-ment provide the mostly unconscious basis for our everyday metaphysics, that is, our sense of what is real.
Cognitive science provides a new and important take on an age-old philosophical problem, the problem of what is real and how we can know it, if we can know it. Our sense of what is real begins with and depends crucially upon our bodies, especially our sensorimotor apparatus, which enables us to per-ceive, move, and manipulate, and the detailed structures of our brains, which have been shaped by both evolution and experience.
Neural Beings Must Categorize
Every living being categorizes.Even the amoeba categorizes the things it encounters into food or nonfood, what it moves toward or moves away from.
The amoeba cannot choose whether to categorize; it just does. The same is true at every level of the animal world. Animals categorize food, predators, possible mates, members of their own species, and so on. How animals categorize de-pends upon their sensing apparatus and their ability to move themselves and to manipulate obiects.
Categorization is therefore a consequence of how we are embodied. We have evolved to categorize; if we hadn't, we would not have survived. Categoriza-tion is, for the most part, not a product of conscious reasoning. We categorize as we do because we have the brains and bodies we have and because we inter-act in the world the way we do.
The first and most important thing to realize about categorization is that it is an inescapable consequence of our biological makeup. We are neural beings. Our brains each have 100 billion neurons and 100 trillion synaptic connec-tions. It is common in the brain for information to be passed from one dense ensemble of neurons to another via a relatively sparse set of connections. Whenever this happens, the pattern of activation distriLuted over the first set of neurons is too great to be represented in a one-to-one manner in the sparse set of connections. Therefore, the sparse set of connections necessarily groups together certain input patterns in mapping them across to the output ensemble. Whenever a neural ensemble provides the same output with different inputs, there is neural categorization.
To take a concrete example, each human eye has 100 million light-sensing cells, but only about 1 million fibers leading to the brain. Each incoming image must therefore be redaced in complexity by a factor of 100. That is, informa-tion in each fiber constitutes a "categorization" of the information from about 100 cells. Neural categorization of this sort exists throughout the brain, up through the highest levels of categeries that we can be aware of. When we see trees, we see them as trees, not just as individual objects distinct from one an-other. The same with rocks, houses, windows, doors, and so on.
A small percentage of our categories have been formed by conscious acts of categorization, but most are formed automatically and unconsciously as a re-sult of functioning in the world. Thongh we learn new categories regularly, we cannot make massive changes in our category systems through conscious acts of recategorization (though, through experience in the world, our categories-are subject to unconscious reshaping and partial change). We do not, and can-not, have full conscious control over how we categorize. Even when we think we are deliberately forming new categories, our unconscious categories enter into our choice of possible conscious categories.
Most important, it is not just that our bodies and brains determine tbat we will categorize; they also determine what kinds of categories we will have and what their structure will be. Think of the properties of the human body that contribote to the peculiarities of our conceptual system. We have eyes and ears, arms and legs that work in certain very definite ways and not in others. We have a visnal system, with topographic maps and orientation-sensitive cells, that pro-vides structure for our ability to conceptualize spatial relations. Our abilities to move in the ways we do and to track the motion of other things give motion a major role in our conceptual system. The fact that we have muscles and use them to apply force in certain ways leads to the structure of our system of causal concepts. What is important is not just that we have bodies and that thought is somehow embodied. What is important is that the peculiar nature of our bodies shapes our very possibilities for conceptualization and categorization.
The Inseparability of Categories, Concepts, and Experience
Living systems must categorize. Since we are neural beings, our categories are formed throngh our embodiment. What that means is that the categories we form are part of our experience! They are the structures that differentiate as-pects of our experience into discernible kinds. Categorization is thus not a purely intellectual matter, occorring after the fact of experience. Rather, the formation and use of categories is the stuff of experience. It is part of what our bodies and brains are constantly engaged in.
We cannot, as some meditative traditions suggest, "get beyond" our categories and have a purely uncategorized experience. Neural beings cannot do that. What we call concepts are neural structures that allow us to mentally charac-terize our categories and reason about them. Human categories are typically conceptualized in more than one way, in terms of what are called prototypes. Each prototype is a neural structure that permits us to do some sort of inferen-tial or imaginative task relative to a category. Typical-case prototypes are used in drawing inferences about category members in the absence of any special contextual information. Ideal-case prototypes allow us to evaluate category members relative tO some conceptual standard. (To,see the difference, compare the prototypes for the ideal husband and the typical husband.) Social stereo-types are used to make snap judgments, usually about people. Salient exem-plars (well-known examples) are used for making probability judgments. (For a survey of kinds of conceptual prototypes, see A4, Lakoff 1987.) In short, prototype-based reasoning constitutes a large proportion of the actual reason-ing that we do. Reasoning with prototypes is, indeed, so common that it is in-conceivable that we could function for long without it.
Since most categories are matters of degree (e.g., tall people), we also have graded concepts characterizing degrees along some scale with norms of various kinds for extreme cases, normal cases, not quite normal cases, and so on. Such graded norms are described by what are called linguistic hedges (A4, Lakoff 1972), for example, very, pretty, kind of, barely, and so on. For the sake of im-posing sharp distinctions, we develop what might be called essence prototypes, which conceptualize categories as if they were sharply defined and minimally distinguished from one another.
When we conceptualize categories in this way, we often envision them using a spatial metaphor, as if they were containers, with an interior, an exterior, and a boundary. When we conceptualize categories as containers, we also impose complex hierarchical systems on them, with some category-containers inside other category-containers. Conceptualizing categories as containers hides a great deal of category structure. It hides conceptual prototypes, the graded structures of categories, and the fuzziness of category boundaries.
In short, we form extraordinarily rich conceptual structures for our cate gories and reason about them in many ways that are crucial for our everyda functioning. All of ~ these conceptual structures are, of course, neural structur in our brains. This makes them embodied in the trivial sense that any mental construct is realized neurally. But there is a deeper and more important sense which our concepts are embodied. What makes concepts concepts is their i ferential capacity, their ability to be bound together in ways that yield infe ences. An em60died concept is a neural structure that is artually part of, o, makes use of, the sensorimotor system of our brains. Much of conceptual infer ence is, therefore, sensorimotor inference.
If concepts are, as we believe, embodied in this strong sense, the philosophical consequences are enormous. The locus of reason (conceptual inference would be the same as the locus of perception and motor control, which are bodily functions. If this seems like a radical claim, it is radical only from the perspective of faculty psychology, a philosophy that posits a radical separation between rational abilities and the sensorimotor system. It is not at all radical from the point of view of the brain, which is the joint locus of reason, perception, and movement. The question from the viewpoint of the brain is whether conceptual inference makes use of the same brain structures as perceptual motor inference. In other words, does reason piggyback on perception and motor control? From the perspective of the brain, the locus of all three functions, would be quite natural if it did.
Realism, Inference, and Embodiment
The question of what we take to be real and the question of how we reason are inextricably linked.
Our categories of things in the world determine what we take to be real: trees, rocks, animals, people, buildings, and so on. Our con cepts determine how we reason about those categories. In order to function re alistically in the world, our categories and our forms of reason must "work" very well together; our concepts must characterize the structure of our cate gories sufficiently well enough for us to function.
Mainstream Western philosophy adds to this picture certain claims that we will argue are false. Not trivially false, but so false as to drastically distort our understanding of what human beings are, what the mind and reason are, what causation and morality are, and what our place is in the universe.
Here ar those claims:
1. Reality comes divided up into categories that exist independent of the specific properties of human minds, brains, or bodies.
2. The world has a rational structure: The relationships among categories in the world are characterized by a transcendent oruniversal reason, which is independent of any peculiarities of human minds, brains, and bodies.
3. The concepts used by mind-, brain-, and body-free reason correctly characterize the mind-, brain-, and body-free categories of reality.
4. Human reason is the capacity of the human mind to use transcendent reason, or at least a portion of it. Human reason may be performed by the human brain, but the structure of human reason is defined by transcendent reason, independent of human bodies or brains. Thus, the structure of human reason is disembodied.
5. Human concepts are the concepts of transcendent reason. They are therefore defined independent of human brains or bodies, and so they too are disembodied.
6. Human concepts therefore characterize the objective categories of mind-, brain, and body-free reality. That is, the world has a unique, fixed category structure, and we all know it and use it when we are rea-soning correctly.
7. What makes us essentially human is our capacity for disembodied reason.
8. Since transcendent reason is culture-free, what makes us essentially hu-man is not our capacity for colture or for interpersonal relations.
9. Since reason is disembodied, what makes us essentially human is not our relation to the material world. Our essential humanness has noth-ing to do with our connection to nature or to art or to music or to any-thing of the senses.
Much of the history of mainstream Western philosophy consists of exploring variations on these themes and drawing out the consequences of these claims. A given philosopher may not hold all of these tenets in the strong form that we have stated them; however, together these claims form a picture of concepts, reason, and the world that any student of philosophy will be familiar with. If they are false, then large parts of the Western philosophical tradition and many of our most coinmon beliefs have to be rethought.
These tenets were not adopted on the basis of empirical evidence. They arose instead out of a priori philosophy. Contemporary cognitive science calls this entire philosophical worldview into serious question on empirical grounds. Here is the reason why cognitive science has a crucial bearing on these issues.
At the heart of this worldview are tenets 4, 5, and 6that human reason and human concepts are mind-, brain-, and body-free and characterize objective, external reality. If these tenets are false, the whole worldview collapses.
Suppose human concepts and human reason are body- and brain-dependent. Sup-pose they are shaped as much by the body and brain as by reality. Then the body and brain are essential to our humanity. Moreover, our notion of what reality is changes. There is no reason whatever to believe that there is a disem-bodied reason or that the world comes neatly carved up into categories or that the categories of our mind are the categories of the world.
If tenets 4, 5, and 6 are empirically incorrect, then we have a lot of rethinking to do about who we are and what our place is in the universe.
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