Foundational Issues in Artificial Intelligence and Cognitive Science:
Impasse and Solution.
Mark H. Bickhard
AT&T Bell Laboratories
Now in paperback!
The book focuses on a conceptual flaw in contemporary artificial intelligence and cognitive science. Many people have discovered diverse manifestations and facets of this flaw, but the central conceptual impasse is at best only partially perceived. Its consequences, nevertheless, visit themselves as distortions and failures of multiple research projects -- and make impossible the ultimate aspirations of the fields.
The impasse concerns a presupposition concerning the nature of representation -- that all representation has the nature of encodings: encodingism. Encodings certainly exist, but encodingism is at root logically incoherent; any programmatic research predicated on it is doomed to distortion and ultimate failure.
The impasse and its consequences -- and steps away from that impasse -- are explored in a large number of projects and approaches. These include SOAR, CYC, PDP, situated cognition, subsumption architecture robotics, and the frame problems -- a general survey of the current research in AI and Cognitive Science emerges.
Interactivism, an alternative model of representation, is proposed and examined.
The central point of Foundational Issues in Artificial Intellligence and Cognitive Science -- Impasse and Solution is that there is a conceptual flaw in contemporary approaches to artificial intelligence and cognitive science, a flaw that makes impossible the ultimate aspirations of these fields. Many people have discovered diverse manifestations and facets of this flaw, but the central conceptual impasse is only partially perceived. The consequences, nevertheless, visit themselves as distortions and failures of research projects across the fields.
The locus of the impasse concerns a common assumption or presupposition that underlies all parts of the field -- a presupposition concerning the nature of representation. We call this assumption "encodingism", the assumption that representation is fundamentally constituted as encodings. This assumption, in fact, has been dominant throughout Western history. We argue that it is at root logically incoherent, and, therefore, that any programmatic research predicated on it is doomed to distortion and ultimate failure.
On the other hand, encodings clearly do exist, and therefore are clearly possible, and we show how that could be -- but they cannot be the foundational form of representation. Similarly, contemporary encoding approaches are enormously powerful, and major advances have been made within these dominant programmatic frameworks -- but the encodingism flaw in those frameworks limit their ultimate possibilities, and will frustrate efforts toward the programmatic goal of understanding and constructing minds.
The book characterizes and demonstrates this impasse, discusses a number of partial recognitions of and movements away from it, and then traces its consequences in a large number of projects and approaches within the fields. These include SOAR, CYC, PDP, situated cognition, subsumption architecture robotics, and the frame problems. In surveying the consequences of the impasse, we also provide a general survey of the current research in AI and Cognitive Science per se.
We do not propose an unsolvable impasse, and, in fact, present an alternative that does resolve that impasse. This is developed for contrast, for perspective, to demonstrate that there is an alternative, and to explore some of its nature. We end with an exploration of some of the architectural implications of the alternative -- called interactivism -- and argue that such architectures are 1) not subject to the encodingism incoherence 2) more powerful than Turing machines, 3) more consistent with properties of central nervous system functioning than other contemporary approaches, and 4) capable of resolving the many problematics in the field that we argue are in fact manifestations of the underlying impasse.
The audience for this book will include researchers, academics, and students in artificial intelligence, cognitive science, robotics, cognitive psychology, philosophy of mind and language, natural language processing, connectionism, and learning. The focus of the book is on the nature of representation, and representation permeates everywhere -- so also, therefore, do the implications of our critique and our alternative permeate everywhere.
Mark H. Bickhard
AT&T Bell Laboratories
Elsevier Science Publishers
Preface xi Introduction 1 A PREVIEW 2 I GENERAL CRITIQUE 5 1 Programmatic Arguments 7 CRITIQUES AND QUALIFICATIONS 8 DIAGNOSES AND SOLUTIONS 8 IN-PRINCIPLE ARGUMENTS 9 2 The Problem of Representation 11 ENCODINGISM 11 Circularity 12 Incoherence - The Fundamental Flaw 13 A First Rejoinder 15 The Necessity of an Interpreter 17 3 Consequences of Encodingism 19 LOGICAL CONSEQUENCES 19 Skepticism 19 Idealism 20 Circular Microgenesis 20 Incoherence Again 20 Emergence 21 4 Responses to the Problems of Encodings 25 FALSE SOLUTIONS 25 Innatism 25 Methodological Solipsism 26 Direct Reference 27 External Observer Semantics 27 Internal Observer Semantics 28 Observer Idealism 29 Simulation Observer Idealism 30 SEDUCTIONS 31 Transduction 31 Correspondence as Encoding: Confusing Factual and Epistemic Correspondence 32 5 Current Criticisms of AI and Cognitive Science 35 AN APORIA 35 Empty Symbols 35 ENCOUNTERS WITH THE ISSUES 36 Searle 36 Gibson 40 Piaget 40 Maturana and Varela 42 Dreyfus 42 Hermeneutics 44 6 General Consequences of the Encodingism Impasse 47 REPRESENTATION 47 LEARNING 47 THE MENTAL 51 WHY ENCODINGISM? 51 II INTERACTIVISM: AN ALTERNATIVE TO ENCODINGISM 53 7 The Interactive Model 55 BASIC EPISTEMOLOGY 56 Representation as Function 56 Epistemic Contact: Interactive Differentiation and Implicit Definition 60 Representational Content 61 EVOLUTIONARY FOUNDATIONS 65 SOME COGNITIVE PHENOMENA 66 Perception 66 Learning 69 Language 71 8 Implications for Foundational Mathematics 75 TARSKI 75 Encodings for Variables and Quantifiers 75 Tarski's Theorems and the Encodingism Incoherence 76 Representational Systems Adequate to Their Own Semantics 77 Observer Semantics 78 Truth as a Counterexample to Encodingism 79 TURING 80 Semantics for the Turing Machine Tape 81 Sequence, But Not Timing 81 Is Timing Relevant to Cognition? 83 Transcending Turing Machines 84 III ENCODINGISM: ASSUMPTIONS AND CONSEQUENCES 87 9 Representation: Issues within Encodingism 89 EXPLICIT ENCODINGISM IN THEORY AND PRACTICE 90 Physical Symbol Systems 90 The Problem Space Hypothesis 98 SOAR 100 PROLIFERATION OF BASIC ENCODINGS 106 CYC - Lenat's Encyclopedia Project 107 TRUTH-VALUED VERSUS NON-TRUTH-VALUED 118 Procedural vs Declarative Representation 119 PROCEDURAL SEMANTICS 120 Still Just Input Correspondences 121 SITUATED AUTOMATA THEORY 123 NON-COGNITIVE FUNCTIONAL ANALYSIS 126 The Observer Perspective Again 128 BRIAN SMITH 130 Correspondence 131 Participation 131 No Interaction 132 Correspondence is the Wrong Category 133 ADRIAN CUSSINS 134 INTERNAL TROUBLES 136 Too Many Correspondences 137 Disjunctions 138 Wide and Narrow 140 Red Herrings 142 10 Representation: Issues about Encodingism 145 SOME EXPLORATIONS OF THE LITERATURE 145 Stevan Harnad 145 Radu Bogdan 164 Bill Clancey 169 A General Note on Situated Cognition 174 Rodney Brooks: Anti-Representationalist Robotics 175 Agre and Chapman 178 Benny Shanon 185 Pragmatism 191 Kuipers' Critters 195 Dynamic Systems Approaches 199 A DIAGNOSIS OF THE FRAME PROBLEMS 214 Some Interactivism-Encodingism Differences 215 Implicit versus Explicit Classes of Input Strings 217 Practical Implicitness: History and Context 220 Practical Implicitness: Differentiation and Apperception 221 Practical Implicitness: Apperceptive Context Sensitivities 222 A Counterargument: The Power of Logic 223 Incoherence: Still another corollary 229 Counterfactual Frame Problems 230 The Intra-object Frame Problem 232 11 Language 235 INTERACTIVIST VIEW OF COMMUNICATION 237 THEMES EMERGING FROM AI RESEARCH IN LANGUAGE 239 Awareness of the Context-dependency of Language 240 Awareness of the Relational Distributivity of Meaning 240 Awareness of Process in Meaning 242 Toward a Goal-directed, Social Conception of Language 247 Awareness of Goal-directedness of Language 248 Awareness of Social, Interactive Nature of Language 252 Conclusions 259 12 Learning 261 RESTRICTION TO A COMBINATORIC SPACE OF ENCODING 261 LEARNING FORCES INTERACTIVISM 262 Passive Systems 262 Skepticism, Disjunction, and the Necessity of Error for Learning 266 Interactive Internal Error Conditions 267 What Could be in Error? 270 Error as Failure of Interactive Functional Indications - of Interactive Implicit Predications 270 Learning Forces Interactivism 271 Learning and Interactivism 272 COMPUTATIONAL LEARNING THEORY 273 INDUCTION 274 GENETIC AI 275 Overview 276 Convergences 278 Differences 278 Constructivism 281 13 Connectionism 283 OVERVIEW 283 STRENGTHS 286 WEAKNESSES 289 ENCODINGISM 292 CRITIQUING CONNECTIONISM AND AI LANGUAGE APPROACHES 296 IV SOME NOVEL ARCHITECTURES 299 14 Interactivism and Connectionism 301 INTERACTIVISM AS AN INTEGRATING PERSPECTIVE 301 Hybrid Insufficiency 303 SOME INTERACTIVIST EXTENSIONS OF ARCHITECTURE 304 Distributivity 304 Metanets 307 15 Foundations of an Interactivist Architecture 309 THE CENTRAL NERVOUS SYSTEM 310 Oscillations and Modulations 310 Chemical Processing and Communication 311 Modulatory "Computations" 312 The Irrelevance of Standard Architectures 313 A Summary of the Argument 314 PROPERTIES AND POTENTIALITIES 317 Oscillatory Dynamic Spaces 317 Binding 318 Dynamic Trajectories 320 "Formal" Processes Recovered 322 Differentiators In An Oscillatory Dynamics 322 An Alternative Mathematics 323 The Interactive Alternative 323 V CONCLUSIONS 325 16 Transcending the Impasse 327 FAILURES OF ENCODINGISM 327 INTERACTIVISM 329 SOLUTIONS AND RESOURCES 330 TRANSCENDING THE IMPASSE 331 References 333 Index 367
Artificial Intelligence and Cognitive Science are at a foundational impasse which is at best only partially recognized. This impasse has to do with assumptions concerning the nature of representation: standard approaches to representation are at root circular and incoherent. In particular, Artificial Intelligence research and Cognitive Science are conceptualized within a framework that assumes that cognitive processes can be modeled in terms of manipulations of encoded symbols. Furthermore, the more recent developments of connectionism and Parallel Distributed Processing, even though the issue of manipulation is contentious, share the basic assumption concerning the encoding nature of representation. In all varieties of these approaches, representation is construed as some form of encoding correspondence. The presupposition that representation is constituted as encodings, while innocuous for some applied Artificial Intelligence research, is fatal for the further reaching programmatic aspirations of both Artificial Intelligence and Cognitive Science.
First, this encodingist assumption constitutes a presupposition about a basic aspect of mental phenomena -- representation -- rather than constituting a model of that phenomenon. Aspirations of Artificial Intelligence and Cognitive Science to provide any foundational account of representation are thus doomed to circularity: the encodingist approach presupposes what it purports to be (programmatically) able to explain. Second, the encoding assumption is not only itself in need of explication and modeling, but, even more critically, the standard presupposition that representation is essentially constituted as encodings is logically fatally flawed. This flaw yields numerous subsidiary consequences, both conceptual and applied.
This book began as an article attempting to lay out this basic critique at the programmatic level. Terveen suggested that it would be more powerful to supplement the general critique with explorations of actual projects and positions in the fields, showing how the foundational flaws visit themselves upon the efforts of researchers. We began that task, and, among other things, discovered that there is no natural closure to it -- there are always more positions that could be considered, and they increase in number exponentially with time. There is no intent and no need, however, for our survey to be exhaustive. It is primarily illustrative and demonstrative of the problems that emerge from the underlying programmatic flaw. Our selections of what to include in the survey have had roughly three criteria. We favored: 1) major and well known work, 2) positions that illustrate interesting deleterious consequences of the encodingism framework, and 3) positions that illustrate the existence and power of moves in the direction of the alternative framework that we propose. We have ended up, en passant, with a representative survey of much of the field. Nevertheless, there remain many more positions and research projects that we would like to have been able to address.
The book has gestated and grown over several years. Thanks are due to many people who have contributed to its development, with multitudinous comments, criticisms, discussions, and suggestions on both the manuscript and the ideas behind it. These include, Gordon Bearn, Lesley Bickhard, Don Campbell, Robert Campbell, Bill Clancey, Bob Cooper, Eric Dietrich, Carol Feldman, Ken Ford, Charles Guignon, Cliff Hooker, Norm Melchert, Benny Shanon, Peter Slezak, and Tim Smithers. Deepest thanks are also due to the Henry R. Luce Foundation for support to Mark Bickhard during the final years of this project.
Mark H. Bickhard
Henry R. Luce Professor of
Cognitive Robotics & the Philosophy of Knowledge
Department of Psychology
17 Memorial Drive East
Bethlehem, PA 18015
Human Computer Interface Research
AT&T Bell Laboratories
600 Mountain Avenue
Murray Hill, NJ 07974
Identifies a fundamental premise about the nature of representation that underlies much of Cognitive Science -- that representation is constituted as encodings.
Explores fatal flaws with this premise.
Surveys major projects within Cognitive Science and Artificial Intelligence.
Shows how they embody the encodingism premise, and how they are limited by it.
Identifies movements within Cognitive Science and AI away from encodingism.
Presents an alternative to encodingism -- interactivism.
Demonstrates that interactivism avoids the fatal flaws of encodingisms, and that it provides a coherent framework for understanding representation.
Unifies insights from the various movements in Cognitive Science away from encodingism.
Sketches an interactivist cognitive architecture.
Simulation of Cognitive Processes
Artificial Intelligence, Knowledge Engineering, Expert Systems
Human Information Processing
Philosophy of Language
Philosophy of Mind
Dynamic Systems and Behavior
Theory of Computation
ISBN 0 444 82520 7
ISBN 0 444 82048 5
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