Fluid Concepts And Creative Analogies
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''Fluid Concepts and Creative Analogies: Computer Models of the Fundamental Mechanisms of Thought'' is a 1995 book by
Douglas Hofstadter Douglas Richard Hofstadter (born 15 February 1945) is an American cognitive and computer scientist whose research includes concepts such as the sense of self in relation to the external world, consciousness, analogy-making, Strange loop, strange ...
and other members of the Fluid Analogies Research Group exploring the mechanisms of
intelligence Intelligence has been defined in many ways: the capacity for abstraction, logic, understanding, self-awareness, learning, emotional knowledge, reasoning, planning, creativity, critical thinking, and problem-solving. It can be described as t ...
through
computer model Computer simulation is the running of a mathematical model on a computer, the model being designed to represent the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be determin ...
ing. It contends that the notions of
analogy Analogy is a comparison or correspondence between two things (or two groups of things) because of a third element that they are considered to share. In logic, it is an inference or an argument from one particular to another particular, as oppose ...
and fluidity are fundamental to explain how the human
mind The mind is that which thinks, feels, perceives, imagines, remembers, and wills. It covers the totality of mental phenomena, including both conscious processes, through which an individual is aware of external and internal circumstances ...
solves problems and to create computer programs that show intelligent behavior. It analyzes several computer programs that members of the group have created over the years to solve problems that require intelligence. It was the first book ever sold by
Amazon.com Amazon.com, Inc., doing business as Amazon, is an American multinational technology company engaged in e-commerce, cloud computing, online advertising, digital streaming, and artificial intelligence. Founded in 1994 by Jeff Bezos in Bellevu ...
.


Origin of the book

The book is a collection of revised articles that appeared in precedence, each preceded by an introduction by Hofstadter. They describe the scientific work by him and his collaborators in the 1980s and 1990s. The project started in the late 1970s at Indiana University. In 1983 he took a sabbatical year at MIT, working in
Marvin Minsky Marvin Lee Minsky (August 9, 1927 – January 24, 2016) was an American cognitive scientist, cognitive and computer scientist concerned largely with research in artificial intelligence (AI). He co-founded the Massachusetts Institute of Technology ...
's Artificial Intelligence Lab. There he met and collaborated with Melanie Mitchell, who then became his doctoral student. Subsequently, Hofstadter moved to the University of Michigan, where the FARG (Fluid Analogies Research Group) was founded. Eventually he returned to Indiana University in 1988, continuing the FARG research there. The book was written during a sabbatical year at the Istituto per la Ricerca Scientifica e Tecnologica in Trento, Italy..


Publication

Upon publication,
Jon Udell Jon Udell is a freelance journalist. From 2007 to 2014 he was "Technology evangelist, Evangelist" at Microsoft. Previously he was lead analyst for the InfoWorld Test Center. Udell is author of ''Practical Internet Groupware'', published in 1999 ...
, a
BYTE The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable un ...
senior technical editor-at-large said:
Fifteen years ago, '' Gödel, Escher, Bach: An Eternal Golden Braid'' exploded on the literary scene, earning its author a
Pulitzer prize The Pulitzer Prizes () are 23 annual awards given by Columbia University in New York City for achievements in the United States in "journalism, arts and letters". They were established in 1917 by the will of Joseph Pulitzer, who had made his fo ...
and a monthly column in ''
Scientific American ''Scientific American'', informally abbreviated ''SciAm'' or sometimes ''SA'', is an American popular science magazine. Many scientists, including Albert Einstein and Nikola Tesla, have contributed articles to it, with more than 150 Nobel Pri ...
''. Douglas Hofstadter's exuberant synthesis of math, music, and art, and his inspired thought experiments with "tangled hierarchy," recursion, pattern recognition, figure/ground reversal, and self-reference, delighted armchair philosophers and AI theorists. But in the end, many people believed that these intellectual games yielded no useful model of cognition on which to base future AI research. Now ''Fluid Concepts and Creative Analogies'' presents that model, along with the computer programs Hofstadter and his associates have designed to test it. These programs work in stripped-down yet surprisingly rich microdomains.
On April 3, 1995, ''Fluid Concepts and Creative Analogies'' became the first book ordered online by an Amazon.com customer.


Chapters and authors

* To Seek Whence Cometh a Sequence (D.H.) * The Architecture of Jumbo (D.H.) * Numbo: A Study in Cognition and Recognition ( Daniel Defays) * High-level Perception, Representation, and Analogy: A Critique of Artificial-intelligence Methodology (
David Chalmers David John Chalmers (; born 20 April 1966) is an Australian philosopher and cognitive scientist, specializing in philosophy of mind and philosophy of language. He is a professor of philosophy and neural science at New York University, as well ...
, Robert French, and D.H.) * The Copycat Project: A Model of Mental Fluidity and Analogy-making (D.H. and Melanie Mitchell) * Perspectives on Copycat: Comparisons with Recent Work (Melanie Mitchell and D.H.) * Prolegomena to Any Future Metacat (D.H.) * Tabletop, BattleOp, Ob-Platte, Potelbat, Belpatto, Platobet (D.H. and Robert French) * The Emergent Personality of Tabletop, a Perception-based Model of Analogy-making (D.H. and Robert French) * Letter Spirit: Esthetic Perception and Creative Play in the Rich Microcosm of the Roman Alphabet (D.H. and Gary McGraw)


Summary of chapters


Chapter 1: To Seek Whence Cometh a Sequence

The first AI project by Hofstadter stemmed from his teenage fascination with number sequences. When he was 17, he studied the way that
triangular A triangle is a polygon with three corners and three sides, one of the basic shapes in geometry. The corners, also called ''vertices'', are zero-dimensional points while the sides connecting them, also called ''edges'', are one-dimensional ...
and
square numbers In mathematics, a square number or perfect square is an integer that is the square of an integer; in other words, it is the product of some integer with itself. For example, 9 is a square number, since it equals and can be written as . The us ...
interleave, and eventually found a recursive relation describing it. In his first course on AI, he set to the students and to himself the task of writing a program that could extrapolate the rule by which a numeric sequence is generated. He discusses
breadth-first Breadth-first search (BFS) is an algorithm for searching a tree data structure for a node that satisfies a given property. It starts at the tree root and explores all nodes at the present depth prior to moving on to the nodes at the next dept ...
and
depth-first Depth-first search (DFS) is an algorithm for traversing or searching tree or graph data structures. The algorithm starts at the root node (selecting some arbitrary node as the root node in the case of a graph) and explores as far as possible al ...
techniques, but eventually concludes that the results represent
expert system In artificial intelligence (AI), an expert system is a computer system emulating the decision-making ability of a human expert. Expert systems are designed to solve complex problems by reasoning through bodies of knowledge, represented mainly as ...
s that incarnate a lot of technical knowledge but don't shine much light on the mental processes that humans use to solve such puzzles. Instead he devised a simplified version of the problem, called SeekWhence, where sequences are based on very simple basic rules not requiring advanced mathematical knowledge. He argues that
pattern recognition Pattern recognition is the task of assigning a class to an observation based on patterns extracted from data. While similar, pattern recognition (PR) is not to be confused with pattern machines (PM) which may possess PR capabilities but their p ...
, analogy, and fluid working hypotheses are fundamental to understand how humans tackle such problems.


Chapter 2: The Architecture of Jumbo

Jumbo is a program to solve jumbles, word puzzles consisting in five or six scrambled letters that need to be
anagram An anagram is a word or phrase formed by rearranging the letters of a different word or phrase, typically using all the original letters exactly once. For example, the word ''anagram'' itself can be rearranged into the phrase "nag a ram"; which ...
med to form an English word. The resulting word does not need to be a real one but just to a plausible, that is, to consists of a sequence of letters that is normal in English. The constituent elements of Jumbo are the following: * The "chunkabet": a database of chunks, small sequences of letters, with a numeric value giving their strength as possible components of a word. * The "
cytoplasm The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell a ...
": a loose data structure containing partial associations of letter, modeling a form of
working memory Working memory is a cognitive system with a limited capacity that can Memory, hold information temporarily. It is important for reasoning and the guidance of decision-making and behavior. Working memory is often used synonymously with short-term m ...
. The name is inspired by the place in a cell where molecular fragments are assembled into proteins. * The "Coderack": a structure containing "codelets", small pieces of programs that are waiting to be executed in the cytoplasm; the codelet that is executed next is chosen non-deterministically, based on urgencies attached to them; a codelet may form new associations, break down old ones, or generate more codelets. A "temperature" is associated to the present state of the cytoplasm; it determines how probable it is that a destructive codelet is executed. There is a "freezing" temperature at which no destruction can occur anymore: a solution has been found.


Chapter 3: Numbo: A Study in Cognition and Recognition

Numbo is a program by Daniel Defays that tries to solve numerical problems similar to those used in the French game "Le compte est bon". The game consists in combining some numbers called "bricks", using the operations of multiplication, addition, and subtraction, to obtain a given result. The program is modeled on Jumbo and Copycat and uses a permanent network of known mathematical facts, a working memory in the form of a cytoplasm, and a coderack containing codelets to produce free associations of bricks in order to arrive at the result.


Chapter 4: Highlevel Perception, Representation, and Analogy

The chapter subtitle ''A Critique of Artificial-intelligence Methodology'' indicates that this is a polemical article, in which
David Chalmers David John Chalmers (; born 20 April 1966) is an Australian philosopher and cognitive scientist, specializing in philosophy of mind and philosophy of language. He is a professor of philosophy and neural science at New York University, as well ...
, Robert French, and Hofstadter criticize most of the research going on at that time (the early '80s) as exaggerating results and missing the central features of human intelligence. Some of these AI projects, like the
structure mapping engine In artificial intelligence and cognitive science, the structure mapping engine (SME) is an implementation in software of an algorithm for analogical matching based on the psychological theory of Dedre Gentner. The basis of Gentner's structure-mapp ...
(SME), claimed to model high faculties of the human mind and to be able to understand literary analogies and to rediscover important scientific breakthroughs. In the introduction, Hofstadter warns about the
Eliza effect In computer science, the ELIZA effect is a tendency to project human traits — such as experience, semantic comprehension or empathy — onto rudimentary computer programs having a textual interface. ELIZA was a symbolic AI chatbot developed in 1 ...
that leads people to attribute understanding to a computer program that only uses a few stock phrases. The authors claim that the input data for such impressive results are already heavily structured in the direction of the intended discovery and only a simple matching task is left to the computer. Their main claim is that it is impossible to model high-level cognition without at the same time modeling low-level perception. While cognition is necessarily based on perception, they argue that it in turn influences perception itself. Therefore, a sound AI project should try to model the two together. In a slogan repeated several times throughout the book: ''cognition is recognition''. Since human perception is too complex to be modelled by available technology, they favor the restriction of AI projects to limited domains like the one used for the Copycat project.


Chapter 5: The Copycat Project

This chapter presents, as stated in the full title, ''A Model of Mental Fluidity and Analogy-making''. It is a description of the architecture of the Copycat program, developed by Hofstadter and Melanie Mitchell. The field of application of the program is a domain of short alphabetic sequences. A typical puzzle is: ''If abc were changed to abd, how would you change ijk in the same way?''. The program tries to find an answer using a strategy supposedly similar to the way the human mind tackles the question. Copycat has three major components: *The ''Slipnet'', a model of long-term memory in humans. It contains concepts of various degrees of abstraction, from the letter types to the notion of ''opposite''. Concepts are connected with links indicating their similarity. The activation of a node may cause the activation of a neighbor with a probability proportional to the inverse of the length of their link. The lengths of these links are not static; they have a value at the beginning but they may change elastically during computation according to the partial results achieved. *The ''Workspace'', a model of short-term memory. Here partial structures are constructed and dismantled. The temporary results may cause the activation of concepts in the slipnet. A ''temperature'' measures the satisfaction of the program with the structure obtained at each moment. High temperature means dissatisfaction and leads to the adoption of a different strategy. Low temperature means satisfaction and the continuation of the present strategy. *The ''Coderack'', a collection of ''codelets'', that is small fragments of code, that wait to be selected and executed in the workspace. Each has a weight associated to it that determined its probability to be selected for execution. The resulting software displays emergent properties. It works according to a '' parallel terraced scan'' that runs several possible processes at the same time. It shows mental fluidity in that concepts may ''slip'' into similar ones. It emulates human behavior in tending to find the most obvious solutions most of the time but being more satisfied (as witnessed by low temperature) by more clever and deep answers that it finds more rarely.


Chapter 6: Perspectives on Copycat

This chapter compares Copycat with other recent (at the time) work in
artificial intelligence Artificial intelligence (AI) is the capability of computer, computational systems to perform tasks typically associated with human intelligence, such as learning, reasoning, problem-solving, perception, and decision-making. It is a field of re ...
. Specifically, it matches it with the claimed results from the
structure mapping engine In artificial intelligence and cognitive science, the structure mapping engine (SME) is an implementation in software of an algorithm for analogical matching based on the psychological theory of Dedre Gentner. The basis of Gentner's structure-mapp ...
SME and the Analogical Constraint Mapping Engine (ACME). The authors' judgment is that those programs suffer from two defects: Their input is pre-structured by the developers to highlight the analogies that the software is supposed to find; and the general architecture of the programs is serial and deterministic rather than parallel and stochastic like Copycat's, which they consider psychologically more plausible. Severe criticism is put on the claim that these tools can solve "real-life" problems. In fact, only the terms used in the example suggest that the input to the programs comes from a concrete situation. The logical structures don't actually imply any meaning for the term. Finally a more positive assessment is given to two other projects: Indurkhya' PAN model and Kokinov's AMBR system.


Chapter 7: Prolegomena to Any Future Metacat

This chapter looks at those aspects of human creativity that are not yet modeled by Copycat and lays down a research plan for a future extension of the software. The main missing element is the mind's ability to observe itself and reflect on its own thinking process. Also important is the ability to learn and to remember the results of the mental activity. The creativity displayed in finding analogies should be applicable at ever higher levels: making analogies between analogies (expression inspired by the title of a book by
Stanislaw Ulam Stanislav and variants may refer to: People *Stanislav (given name), a Slavic given name with many spelling variations (Stanislaus, Stanislas, Stanisław, etc.) Places * Stanislav, Kherson Oblast, a coastal village in Ukraine * Stanislaus County, ...
), analogies between these second-order analogies, and so on.


Chapter 8: Tabletop, BattleOp, Ob-Platte, Potelbat, Belpatto, Platobet

Another of Hofstadter's students, Robert French, was assigned the task of applying the architecture of Copycat to a different domain, consisting in analogies between objects lying on a table in a coffeehouse. The resulting program was named Tabletop. The authors present a different and vaster domain to justify the relevance of attacking such a trivial-seeming project. The alternative domain is called Ob-Platte and consists in discovering analogies between geographical locations in different regions or countries. Once again arguments are offered against a brute-force approach, which would work on the small Tabletop domain but would become unfeasible on the larger Ob-Platte domain. Instead a parallel non-deterministic architecture is used, similar to the one adopted by the Copycat project.


Chapter 9: The Emergent Personality of Tabletop, a Perception-based Model of Analogy-making

In the premise to the chapter, title ''The Knotty Problem of Evaluating Research'', Hofstadter considers the question of how research in AI should be assessed. He argues against a strict adherence to a match between the results of an AI program with the average answer of human test subjects. He gives two reasons for his rejection: the AI program is supposed to emulate creativity, while an average of human responses will delete any original insight by any of the single subjects; and the architecture of the program should be more important that its mere functional description. In the main article, the architecture of Tabletop is described: it is strongly inspired by that of Copycat and consists of a Slipnet, a Workspace, and a Corerack.


Chapter 10: Letter Spirit

This last chapter is about a more ambitious project that Hofstadter started with student Gary McGraw. The microdomain used is that of grid fonts: typographic alphabets constructed using a rigid system of small rigid components. The goal is to construct a program that, given only a few or just one letter from the grid font, can generate the whole alphabet ''in the same style''. The difficulty lies in the ambiguity and undefinability of ''style''. The projected program would have a structure very similar to that of Jumble, Numble, Copycat, and Tabletop.


Epilogue

In the concluding part of the book, Hofstadter analyses some AI projects with a critical eye. He finds that today's AI is missing the gist of human creativity and is making exaggerated claims. The project under scrutiny are the following.
AARON According to the Old Testament of the Bible, Aaron ( or ) was an Israelite prophet, a high priest, and the elder brother of Moses. Information about Aaron comes exclusively from religious texts, such as the Hebrew Bible, the New Testament ...
, a computer artist that can draw images of people in outdoor settings in a distinctive style reminiscent of that of a human artist; criticism: the program doesn't have any understanding of the objects it draws, it just uses some graphical algorithms with some randomness thrown in to generate different scenes at every run and to give the style a more natural feel. Racter, a computer author that wrote a book entitled ''The Policeman's Beard Is Half Constructed''. Although some of the prose generated by the program is quite impressive, due in part to the
Eliza effect In computer science, the ELIZA effect is a tendency to project human traits — such as experience, semantic comprehension or empathy — onto rudimentary computer programs having a textual interface. ELIZA was a symbolic AI chatbot developed in 1 ...
, the computer does not have any notion of plot or of the meaning of the words it uses. Furthermore, the book is made up of selected texts from thousands produced by the computer over several years. AM, a computer mathematician that generates new mathematical concepts. It managed to produce by itself the notion of
prime number A prime number (or a prime) is a natural number greater than 1 that is not a Product (mathematics), product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime ...
and the
Goldbach conjecture Goldbach's conjecture is one of the oldest and best-known unsolved problems in number theory and all of mathematics. It states that every even natural number greater than 2 is the sum of two prime numbers. The conjecture has been shown to ho ...
. As with Racter, the question is how much the programmer filtered the output of the program, keeping only the occasional interesting output. Also, mathematics being a very specialized domain, it is doubtful whether the techniques used can be abstracted to general cognition. Another mathematical program, called Geometry, was celebrated for making an insightful discovery of an original proof that an isosceles triangle has equal base angles. The proof is based on seeing the triangle in two different ways. However, the program generates all possible ways of seeing the triangle, not even knowing that it is the same triangle. Hofstadter concludes with some methodological remarks on the
Turing Test The Turing test, originally called the imitation game by Alan Turing in 1949,. Turing wrote about the ‘imitation game’ centrally and extensively throughout his 1950 text, but apparently retired the term thereafter. He referred to ‘ iste ...
. In his opinion it is still a good definition and he argues that by interacting with a program, a human may be able to have insight not just on its behaviour but also on its structure. However, he criticises the use that is made of it at present: it encourages the development of fancy natural-language interfaces instead of the investigation of deep cognitive faculties.


Editions

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References

{{Douglas Hofstadter 1995 non-fiction books Cognitive science literature Books by Douglas Hofstadter Analogy Books about metaphors