UNIVERSITY OF NAVARRA ECCLESIASTICAL FACULTY OF PHILOSOPHY Mark Telford Georges THE PROBLEM OF STORING COMMON SENSE IN ARTIFICIAL INTELLIGENCE Context in CYC Doctoral dissertation directed by Dr. Jaime Nubiola Pamplona, 2000 1 Table of Contents ABBREVIATIONS ............................................................................................................................. 4 INTRODUCTION............................................................................................................................... 5 CHAPTER I: A SHORT HISTORY OF ARTIFICIAL INTELLIGENCE .................................. 9 1.1. THE ORIGIN AND USE OF THE TERM “ARTIFICIAL INTELLIGENCE”.............................................. 9 1.1.1. Influences in AI................................................................................................................ 10 1.1.2. “Artificial Intelligence” in popular culture..................................................................... 11 1.1.3. “Artificial Intelligence” in Applied AI ............................................................................ 12 1.1.4. Human AI and alien AI....................................................................................................14 1.1.5. “Artificial Intelligence” in Cognitive Science................................................................. 16 1.2. TRENDS IN AI........................................................................................................................... 17 1.2.1. Classical AI ..................................................................................................................... 17 1.2.2. Connectionism ................................................................................................................. 19 1.2.3. Situated robotics.............................................................................................................. 23 1.3. THE PHILOSOPHY OF AI............................................................................................................ 25 1.3.1. Criteria for intelligence ................................................................................................... 25 1.3.2. Hypotheses about intelligence ......................................................................................... 27 1.3.3. The meaning of “thinking things” ................................................................................... 31 1.4. HOW AI HAS FARED AND THE NEED FOR KNOWLEDGE ............................................................. 35 1.4.1. How AI has fared............................................................................................................. 36 1.4.2. The need for knowledge...................................................................................................39 1.5. THE PROBLEM OF STORING COMMON SENSE............................................................................. 41 CHAPTER II: THE CYC EXPERIMENT..................................................................................... 45 2.1. DOUGLAS LENAT, THE CYC PROJECT LEADER ........................................................................ 46 2.2. CYC METHODOLOGY............................................................................................................... 48 2.3. CYC THEORY OF INTELLIGENCE .............................................................................................. 49 2.3.1. The Knowledge Principle ................................................................................................ 49 2.3.2. The Explicit Knowledge Principle................................................................................... 51 2.3.3. Overcoming brittleness.................................................................................................... 52 2.3.4. Coping with novelty: The Breadth Hypothesis ................................................................ 53 2.4. THE UPPER CYC ONTOLOGY.................................................................................................... 57 2.4.1. Basic concepts ................................................................................................................. 59 2.4.2. CYC fundamental vocabulary.......................................................................................... 61 2.4.3. CYC top level vocabulary................................................................................................ 61 2.5. HOW CYC HAS PROGRESSED ................................................................................................... 68 2.5.1. The three stages of CYC development ............................................................................. 68 2 2.5.2. The early years of CYC.................................................................................................... 70 2.5.3. Reworking the representation language.......................................................................... 71 2.5.4. Three important lessons................................................................................................... 72 2.5.5. Applications of CYC ........................................................................................................ 74 2.5.6. CYC today........................................................................................................................ 76 CHAPTER III: CONTEXT IN CYC .............................................................................................. 78 3.1. THE PROBLEM OF CONTEXT IN STORING COMMON SENSE ......................................................... 78 3.1.1. Incorporating context in CYC.......................................................................................... 79 3.1.2. Shortcomings in the original strategy.............................................................................. 81 3.2. RETHINKING CONTEXT............................................................................................................. 85 3.2.1. The elements of shared context........................................................................................ 85 3.2.2. Dimensionalizing context space ...................................................................................... 88 3.3. THE TOP 12 DIMENSIONS OF CONTEXT-SPACE .......................................................................... 91 3.3.1. Dimensions for time and space........................................................................................ 93 3.3.2. Eight other useful dimensions........................................................................................ 103 3.4. CONTEXT SPECIFICATION AND INFERENCE IN THE NEW STRATEGY......................................... 111 CHAPTER IV: PRINCIPLES, STRENGTHS AND WEAKNESSES IN CYC ....................... 114 4.1. CYC METHODOLOGY: PRINCIPLES, STRENGTHS AND WEAKNESSES....................................... 114 4.1.1. The underlying principles of EH.................................................................................... 115 4.1.2. CYC’s methodological strengths ................................................................................... 121 4.1.3. CYC’s methodological weaknesses................................................................................ 121 4.2. CYC THEORY OF INTELLIGENCE: PRINCIPLES, STRENGTHS AND WEAKNESSES ...................... 123 4.2.1. Underlying principles in CYC theory ............................................................................ 124 4.2.2. CYC’s theoretical strengths........................................................................................... 128 4.2.3. CYC’s theoretical weaknesses ....................................................................................... 129 4.3. CONTEXT IN CYC: PRINCIPLES, STRENGTHS AND WEAKNESSES............................................. 130 4.3.1. Underlying principles of context representation in CYC............................................... 131 4.3.2. Strengths of context representation in CYC................................................................... 134 4.3.3. Weaknesses of context representation in CYC............................................................... 135 4.4. THE VALIDITY OF PHILOSOPHICAL EVALUATION IN AI ........................................................... 139 CONCLUSIONS ............................................................................................................................. 141 BIBLIOGRAPHY ........................................................................................................................... 148 WORKS BY DOUGLAS LENAT AND HIS ASSOCIATES ...................................................................... 148 GENERAL BIBLIOGRAPHY.............................................................................................................. 149 3 Abbreviations AAAI American Association for Artificial Intelligence ACM Association of Computing Machines AI Artificial Intelligence ASR Automatic Speach Recognition CBR Case Based Reasoning CYC The name comes from en-CYC-lopedia DCS D. B. Lenat, “The Dimensions of Context Space”, Austin, TX: Cycorp, 1998. EH The Empirical Inquiry Hypothesis KB Knowledge Base NLU Natural Language Understanding OTK D. B. Lenat and E. A. Feigenbaum, 1991, “On the Thresholds of Knowledge”, Artificial Intelligence 47: 185-250. PDP Parallel Distributed Processing 4 Introduction Does computer science have anything to do with philosophy? As a computer scientist myself