Douglas Hofstadter
List of Illustrations
Prologue: The When, the Where, and the Who of This Book
A Short History of FARG and FARGonauts
The Double-Strandedness of FARG's Intellectual Goals
This Book in a Nutshell
Some Vital Acknowledgments
Post Scriptum
1. To Seek Whence Cometh a Sequence
Pattern-Finding as the Core of Intelligence
Triangles between Squares
Dot dot dot...
Introduction to Mathgod
A Strange Pattern Starts to Appear
Reenactment of a Discovery
A Magical Aperiodic Pattern
Pattern Extrapolation as Research Project and Class Assignment
Trying to Reduce a Sequence to Simpler Sequences
Strategies for Controlling a Search
Heuristics, or the Importance of Sniffing Before You Inhale Deeply
Glimpses of a Very Different Type of Architecture
General Intelligence vs. Expert Knowledge
Mathgod Makes a Booboo
Mathgod Redeemed
Aesthetics-Driven Perception
Elegance and Consistency Unravel a Sample Sequence
Number Savvy vs. Pattern Sensitivity
A Droll Interlude
Segmentation and Unification - Intertwined Facets of Pattern Sensitivity
The Austere Microworld of Seek-Whence
Good-bye, Math... Hello, Music!
The Theme Song of the Seek-Whence Project
The Surprisingly Wide Gulf between Researchers' Goals
Typical Sequences in the Seek-Whence Domain
The Deep Problem of Representing Rules Realistically
A Mountain-Chain Sequence
Building Up Islands of Order
Many Levels of Perception, All Going on in Parallel
The Key Role of Analogies
The Mountain-Chain Sequence - Solved
Polishing the Solution
On Deciphering Shorter vs. Longer Messages
Mathematicians' Deep Ambivalence towards Obvious Patterns
Expanding Conceptual Spheres in Mathematics
Common Sense and Expanding Conceptual Spheres
How Far Can a Conceptual Sphere Stretch Before it Pops?
The "Me-Too" Phenomenon
Outward Generalization in the Seek-Whence Domain
Variations on a Theme by Chopin
The Blurry Edge of Essence
Coming Full Circle to Triangles between Squares
From Seek-Whence to Jumbo, Copycat, and Others
2a. The Unconscious Juggling of Mental Objects
The Joy of Anagrams
Letters Go Up, Words Come Down
The Gulf between Virtual Mental Objects and Their Physical Substrate
Jumbo vs. Brute Force
That Fateful Footnote
The Parallel Terraced Scan Meets the Greek System
To Read, or Toreador
To Learn, or Not to Learn
2b. The Architecture of Jumbo
Prologue: Not Mumbo-Jumbo
Jumbo and Jumbles
The Significance of Jumbo's Task Domain
Two Basic Analogies on which Jumbo Rests
Jumbo and Parallelism
Sparks and Affinities
Codelets and the Coderack
The Concept of a Terraced Scan
Romances among the Letters
Bonds, Chains, Gloms, and Membranes
A Single Reality with Many Parallel Counterfactual Musings
Unhappy Gloms, Squeaky Wheels
Looking for Alternative Solutions to a Given Jumble
Totally Rational Choice vs. Rationally Biased Coin-Flipping
Transformations in Jumbo
Entropy-Preserving Transformation
Fluid Data-Structures: A Principal Aim of Jumbo
Entropy-Increasing Transformations
Temperature and Self-Watching
A Self-Sensitive, Self-Driven System
Epilogue: Jumbo's Epiphenomenal Intelligence
3a. Arithmetical Play and Nondeterminism
"Le Compte Est Bon"
The Human Mind as a Stochastic Processor
3b. Numbo: A Study in Cognition and Recognition
Introduction
The Game of Numble
The Architecture of Numbo
The Permanent Network
The Cytoplasm
Codelets
A Sample Run of Numbo
Discussion
Comparison with Other Computer Models
Comparison with Human Performance
Conclusions
4a. The Ineradicable Eliza Effect and Its Dangers
Programs with Apparent Real-World Prowess
The Slippery Slope into the Eliza Effect
"Just This Once"
Can Computers Understand Metaphors by Shakespeare and Plato?
The Dubious Claim of Cross-Domain Analogy-Making
Copycat: A Kid Doing a Somersault
4b. High-level Perception, Representation, and Analogy: A Critique of Artificial-intelligence Methodology
The Problem of Perception
Low-Level and High-Level Perception
Artificial Intelligence and the Problem of Representation
Objectivism and Traditional AI
On the Possibility of a Representation Module
BACON: A Case Study
Models of Analogical Thought
Current Models of Analogical Thought
The Necessity of Fusing High-Level Perception with More Abstract Cognitive Processing
The Utility of Small Domains
Conclusion
5a. Conceptual Halos and Slippability
Analogy Puzzles in the Seek-Whence Domain
The Nancy Reagan of England
Words, Concepts, and Halos
From Conceptual-Halo Slips to Conceptual Slippages
Copycat Is Conceived
5b. The Copycat Project: A Model of Mental Fluidity and Analogy-Making
Copycat and Mental Fluidity
Analogy Problems in the Copycat Domain
Mental Fluidity: Slippages Induced by Pressures
The Intended Universality of Copycat's Microdomain
A Perception-Based, Emergent Architecture for Mental Fluidity
The 3 Major Components of the Copycat Architecture
The Slipnet - Copycat's Network of Platonic Concepts
Conceptual Depth
Activation Flow and Variable Link-Lengths
Concepts as Diffuse, Overlapping Clouds
The Workspace - Copycat's Locus of Perceptual Activity
The Constant Fight for Probabilistic Attention
The Parallel Emergence of Multi-Level Perceptual Structures
The Drive Towards Global Coherence and Towards Deep Concepts
The Coderack - Source of Emergent Pressures in Copycat
Pressures Determine the Speeds of Rival Processes
The Shifting Population of the Coderack
The Emergence of Fluidity in the Copycat Architecture
Commingling Pressures - The Crux of Fluidity
The Parallel Terraced Scan
Time-Evolving Biases
Temperature as a Regulator of Open-Mindedness
Overall Trends during a Run
The Intimate Relation between Randomness and Fluidity
Biased Randomness Gives Each Pressure Its Fair Share
Randomness and Asynchronous Parallelism
A Seeming Paradox: Randomness in the Service of Intelligence
Copycat's Performance: A Forest-Level Overview
The Statistically Emergent Robustness of Copycat
Copycat's "Personality" is Revealed through Bar Graphs
Systematically Studying the Effects of Variant Problems
How Hidden Concepts Emerge from Dormancy
Paradigm shifts in a Microworld
Families of Problems as a "Miniature Turing Test"
Copycat's Performance: A Tree-Level Close-Up
A Problem where Perception Plays a Crucial Role Is Chosen as a Focus
The Story in Quick Strokes
Screen Dumps Tell the Story in Detail
Micro-Anatomy of a Paradigm Shift
Emergency Measures Concert a Serious Snag into a Set of Exploratory Pressures
How Resistance to a Deep Slippage is Overcome - A Tricky Matter
Locking-In of a New View
How Hard Is It to Make this Paradigm Shift?
Conclusion: The Generality of Copycat's Mechanisms
The Crucial Question of Scaling-Up
Shades of Gray and the Mind's Eye
Copycat's Shaded Exploration Strategy
Shades of Gray in the Slipnet
Shades of Gray in the Workspace
Shades of Gray Associated with the Coderack
Dynamic Emergence of Unpredictable Objects and Pathways
6a. Two Early AI Approaches to Analogy
Thomas Evans' Program ANALOGY
Walter Reitman's Argus Program
6b. Perspectives on Copycat: Comparisons with Recent Work
How to Judge Copycat?
SME, the Structure Mapping Engine
Points of Agreement between Copycat and SME
Points of Disagreement between Copycat and SME
ACME, the Analogical Constraint Mapping Engine
Agreements and Disagreements between Copycat and ACME
How Real are These "Real-World" Analogies?
Copycat's Position along the Symbolic/Subsymbolic Spectrum
Postscript
Indurkya's View of Creativity, and the PAN Model
Kokinov's AMBR System -- Associative Memory-Based Reasoning
7a. Retrieval of Old and Invention of New Analogies
The Lifelike Appearance of Copycat
An Axed Pet Analogy
Meta-Analogies, Caricature Analogies, and Memory Retrieval
Analogy-Puzzle Invention as a Cognitive Challenge
7b. Prolegomena to Any Future Metacat
An Incipient Model of Fluidity, Perception, Creativity
Copycat: Self-Aware, But Very Little
Shades of Gray along the Consciousness Continuum
The Key Role of Self-Monitoring in Creativity
A Stab at Defining Creativity
Five Challenges Defining What Any Future Metacat Must Do
8a. Analogy-making in a Coffeehouse
Singin' the Copycat Blues
Mimicking "Real" Analogies in Tabletop's Mini-Universe
8b. Tabletop, BattleOp, Ob-Platte, Potelbat, Belpatto, Platobet
Analogy Problems in Microdomains
"Do This!" Puzzles on a Tabletop
Realistically Modeling Analogy-Makinng on a Highly Idealized Tabletop
A Brute-Force Approach to Tabletop Analogy Problems
Why Developing a Brute-Force Program would Miss the Point
Generality: The Fundamental Goal of the Tabletop Project
Analogy Problems in Scaled-Up Domains
Tabletop Gets Mentally Scaled Up to Global Proportions
BattleOp, in Turn, Gets Cut Down to Reasonable Proportions
Are Ob-Platte Puzzles about Analogical Mapping or Analogical Retrieval?
Fundamental Obstacles Facing a Formula-Based Architecture
A Brute-Force Approach to Ob-Platte Puzzles
Exhaustive Search Is Deeply Wrong
Could Pruning Help Matters?
Shades of Gray Are Needed - But they Quickly Lead Far Outside the Domain
Trying to Capture the "Essence" of a Town
Analogy Problems at all Levels - The Nightmare of a Potentially Infinite Regress
Town Names Alone Constitute a Bottomless Barrel of Worms
What Constitutes a Town?
Violations of Geographical and Conceptual Boundaries
Local vs. Locational Aspects of a Town
Bringing These Ideas Back to Tabletop
Downward Transfer of Lessons from the Big Domain to the Tiny Domain
Crude Mirrorings, in Tabletop, of Some Tricky Ob-Platte Puzzles
Other Tricky Tabletop Problems and Mechanisms Tailor-Made to Handle Them
Concluding Words
9a. The Knotty Problem of Evaluating Research in AI and Cognitive Science
Striving to Simulate the Style of an Individual Human Mind
A Throng of Interacting Subcognitive Mechanisms
How Are Natural-Language Programs Validated?
Concrete Criteria for the Validation of Our Computational Models
The Substrate of Cognition is Culture-Independent
A Crazy Bazaar
CYC
CBR - Case-Based Reasoning
Dustbuster
Soar
Private Hunches vs. Public Stances
9b. The Emergent Personality of Tabletop, a Perception-based Model of Analogy-Making
Striving for Cognitive Generality in a Mundane Microdomain
Perceptual Processes in Tabletop
Structures, Strengths, and Fights for Survival
Codelets and the Interleaving of Perceptual Processes
The Pervasiveness of Dynamic Perceptual Biases
The Gradual Emergence of Coherence
Tabletop Gauges Its Own Progress
Some Differences between Tabletop's and Copycat's Domains
Some Differences between Tabletop's and Copycat's Architectures
Tabletop's Personality as a Statistically Emergent Phenomenon
10a. The Intoxicating World of Alphabets and Their Styles
Infected with Letter Mania from the Word "Go"
From Real Letters to Stick Letters
The Letter Spirit Computer Program Is Born
10b. Letter Spirit: Esthetic Perception and Creative Play in the Rich Microcosm of the Roman Alphabet
The Goal of Imparting a Sense of Deep Style to a Machine
But Hasn't That Already Been Done?
A Non-Creative Computer Model of Letter Design
True Creativity Implies Autonomy
Letters as Rich, Full-Fledged Concepts
Wholes and Roles
Letter and Spirit as Orthogonal Categories
Retreating from Real-World to Microworld Typeface Design
Gridletters and Gridfonts
The Grid Engenders Exotic Letterforms and Wild Styles
The Principal Varieties of Stylistic Determiners
The Spirits behind Four Sample Gridfonts
Creating a Gridfont - A Broad View
The Implementation of Emergent Processing
Four Global Memory Structures
Scratchpad
Conceptual Memory
Visual Focus
Thematic Focus
The Predictable Unpredictability of the Creative Process
Four Interacting Emergent Agents
Imaginer
Drafter
Examiner
Abstractor
The Central Feedback Loop of Creativity
The Strangely Circular Origin of a Style
Towards the Implementation of the Central Feedback Loop
Brief Comments on Related Work in Letter Recognition
A Connectionist Approach to the Letter Spirit Challenge
The Inescapable Temporality of the Act of Creation
Genuine Cognition Is Not a Free Lunch
Epilogue: On Computers, Creativity, Credit, Brain Mechanisms, and the Turing Test
A Somewhat Skeptical Perspective on Computers and Creativity
A Computer Artist
A Computer Author
A Computer Mathematician
Another Computer Mathematician
Plagiarism vs. Creativity
Mechanisms, Probes, and the Turing Test
Brain Structures vs. Cognitive Mechanisms
Some Levels of Description Are Certainly Too Low
The Need for Criteria by Which to Recognize Thinking
Scattering Experiments vs. "Direct" Observation of Phenomena
The Turing Test and the Visibility of Deep Mechanisms
The Turing Test and Basic Research
References
Index
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