AI Magazine Volume 16 Number 3 (1995) (© AAAI) Book Review

heads in a row and turns out right is A Review of merely lucky, not insightful. What, then, would prove that someone was Mental Leaps: a deep maker? Surely, not just one analogy, no matter how suc- Analogy in Creative Thought cessful. It would take a series of fruit- yielding to reveal that someone had the gift of being able to look at diverse situations and see Douglas Hofstadter through to their gists. Having a reliable ability to see to the gist of a situation—now there, I would say, is the gist of analogy-mak- ■ Mental Leaps: Analogy in Creative 1954. To be sure, Ball saw the appeal ing skill. When we say, “Iraq’s kvetch- Thought, Keith Holyoak and Paul of the Korea, Munich, and domino- ing about Iran’s threatening troop chain analogies, but in each, he also Thagard, MIT Press, Cambridge, maneuvers is surely the pot calling saw serious weaknesses; more impor- Massachusetts, 1994, 320 pp., ISBN the kettle black,” we are seeing a situ- tant, he felt he saw deeper similari- 0-262-08233-0. ation on an abstract level, homing in ties to the situation the French had on a phrase that highlights this faced, which led him to his gloomy ne would hardly expect a essence. When Maria inadvertently but accurate predictions of what book on analogy and creativi- swims an extra seventeenth lap in her would happen to American troops if Oty to devote seven pages to first attempt to do a full mile, and Joe they went in. the Vietnam War, but there it is—one says, “Hey, kiddo, did you know you I found this discussion enlighten- of the most informative histories of swam a guinea?”, he is conveying ing, but it left me wondering, Was the period that I have ever read. Of what he’s just witnessed by alluding Ball really so great an analogist? course, the book’s authors, psycholo- to the rather la-di-da British mone- Holyoak and Thagard tell us, “Ball gist Keith Holyoak and philosopher tary unit worth 21 shillings (one had worked as a lawyer for the , have good reason for French government during its period pound plus one extra shilling). this discussion: to focus on the of grief in Vietnam, and he never for- These examples involve putting “analogy war” that went on for years got that historical source” (p. 161). one’s finger on a familiar proverb or in the upper echelons of the U.S. So wasn’t this experience in some even the proverbial mot juste, but government. sense the last war that Ball had been usually there is no mot juste or per- Politicians think by analogy all the fect proverb encapsulating a complex time, and the fates of nations hang situation; in such cases, we are often on their idiosyncratic analogical in- reminded of some experience in our stincts, wise or not. Military leaders, I firmly believe that gist ex- past. Our storehouse of experiences too, are guided by precedents, and traction, the ability to see to includes virtual, as well as real, ones. Holyoak and Thagard ironically note the core of the matter, is the For example, you hear a cynical re- that generals often prepare for the mark about TV to the effect that no war that they last fought. However, key to analogy making— in- show ever has to be any good, merely they also point out that one can se- deed, to all intelligence. Un- better than its mediocre competi- lect one’s precedents in a deeper fortunately, Holyoak and tors—and seemingly up from manner than that. In fact, they de- Thagard do not seem to agree. nowhere bubbles the punch line of a vote three pages to George Ball, un- joke in which Albert Einstein is hur- dersecretary of state in the Johnson riedly putting on his tennis shoes to administration, “who history must escape a bear, and his hiking com- through? Was he not simply using now credit as the greatest American panion Niels Bohr says, “Dear Albert, his own last war as his precedent, political analogist of his time” (p. you can’t outrun the bear!” to which 163), praising him for seeing further just as Dean Rusk and others used Einstein replies, “Ja, ja, Bohr, but all into the Vietnam situation than any- the Korean War as theirs? what I need to outrun is you.” one else in a high-level position. If my analogy between George Ball I firmly believe that gist extraction, Ball, instead of likening the situa- and the Johnny-one-note military the ability to see to the core of the tion in Vietnam in the early 1960s to minds is reasonable, then Ball might matter, is the key to analogy mak- that in Korea 10 years earlier, or to not deserve the label “great analo- ing—indeed, to all intelligence. Un- the British capitulation to Hitler in gist”; having predicted the debacle fortunately, Holyoak and Thagard do Munich, or to the first domino in a for the United States shows merely not seem to agree. At least, they do chain, picked out a different ana- that he happened to have had the not focus any attention on this logue: the situation facing the French good luck to pick the closer analog, “sense for essence,” and it is here before their defeat in Indochina in just as someone who predicts five that they make their greatest mis-

Copyright © 1995, American Association for Artificial Intelligence. All rights reserved. 0738-4602-1995 / $2.00 FALL 1995 75 Book Review take, one that permeates their view of me awake was this: “In this analogy bright sun, blue sky, and on and on? analogy and, therefore, seriously there is…only a modest degree of What to the workplace, the boss, the mars their book. They indicate no ap- similarity between the corresponding job interview, the outfit worn, the preciation for either the essential role first-order relations, such as hunger for nervousness, the sweat, the wait for a or the enormous subtlety of this and desire. The major similarities in- decision, the crushing blow? Of sense for essence. They do not seem volve higher-order relations, most course, these seem to be minor as- to realize the hugeness of the gulf be- notably cause” (p. 31). pects that are not part of the essence tween a full situation as a human per- Of course, being human, I agreed of either event. However, this is ex- ceives it—having no sharp bound- that the sour-grapes–sour-job analogy actly the point! When Holyoak and aries, woven intricately into the was strong. The question was why. I Thagard said there was a one-to-one fabric of one’s knowledge and life ex- was stunned that Holyoak and Tha- correspondence between these situa- periences—and a handful of predicate gard were downplaying the role of tions, they were blurring the notion calculus formulas. For example, they such vivid, gripping, complex themes of story with that of story’s gist. The constantly refer to “the objects,” “the as hunger, desire, frustration, disap- one-to-one correspondence is, of attributes,” “the relations,” and “the pointment, denial, and self-fooling in course, only at the level of the story’s higher-level predicates” in situations, favor of a single abstraction so flat gist. Getting from the story to the as if real situations (for example, Wa- and ordinary that it could serve as story’s gist, something that occurs tergate, a romantic breakup, the abor- the core of any event of any sort. swiftly yet almost invisibly in a hu- tion debate, the O. J. Simpson trial, Such an overstress on causality—a man mind, is as central a mystery of John Searle’s Chinese room scenario) ubiquitous ingredient of events and, as any that exists. came given with absolute, unambigu- therefore, an essentially useless tool However, Holyoak and Thagard talk ous separations into objects, at- for classifying them—would allow about both levels in the same breath, tributes, and so on—as if distilling virtually any pair of events to map pointing to one but meaning the oth- Hamlet or World War II into two onto each other. I was reminded of a er, without even seeming to realize dozen lines of predicate calculus no- time a few years ago when, in a the finesse they are carrying tation were a mechanical task not demonstration of Falkenhainer, For- out—and I, on my first reading, had meriting discussion in a book on bus, and Gentner’s analogy-making happily gone along with them. Once analogy. And troublingly, the authors program SME (a rival to Holyoak and I realized that this conflation of gist glide back and forth so smoothly be- Thagard’s ACME, discussed later), I was with full situation had slipped right tween references to real-world situa- flabbergasted to realize that the chief by me, a long-time skeptic of the tions and references to their tiny, reason SME perceived an analogy be- whole idea, I knew it could happen hand-sculpted, frozen caricatures tween two particular situations was to anyone—even the book’s authors. that, I suspect, many readers will be that both had been encoded (by peo- Indeed, when I then saw such completely unaware of the blur they ple) into predicate-logic trees, each of conflation reoccur over and over are witnessing. whose top-level node was the Lisp again throughout their book, I real- I myself realized the subtlety of atom and! Although the two situa- ized that they might be the least like- this effect in their prose when I read tions indeed were analogous, their ly of all to see the illusion. Let us their discussion of the analogy be- abstract similarity certainly did not now look at this illusion in the con- tween Aesop’s sour grapes fable and stem from the fact that each could be text of their computer model. the story of someone who applies for cast as a pair of subsituations joined To explain the principles of their a job, is turned down, and then says by the dime-a-dozen, flavorless computer program ACME, which maps the job would have been boring any- Boolean connective and. Similarly, formalized situations (or, rather, for- way (p. 31). On first reading it, I was the bland, watery, 99-percent-fat-free malized situation gists!) onto each left with a vague twinge of uneasi- verb cause is not even close to the other, Holyoak and Thagard give, in ness, so I went back and tried it crux of the sour-grapes–sour-job anal- figure 1a, a stripped-down version of again. Suddenly, I saw I had uncriti- ogy. To portray it as such is to bend the analogy between the events that cally bought into Holyoak and Tha- facts in service of an ideology. launched the 1991 Gulf War and gard’s interpretation of these two vi- Awakened to an ideology lurking those that led to World War II (pp. gnettes, momentarily swallowing backstage, I went back over Holyoak 248–250). These lines seem to con- their emphasis on causation’s central and Thagard’s analysis and soon real- tain the gist of each situation, but role (“Desiring the job caused the ized there was not, as I had at first they do so only if you know English person to apply for it, and being docilely accepted, a one-to-one corre- and remember both situations, which turned down caused the person to spondence between the “elements” the program does not. Therefore, a say the job was boring” [p. 31]), as in the vignettes. What corresponds to less deceptive picture of what the well as their plausible-sounding sug- the grapevine or gravity, to physical program is faced with is given by the gestion that “each element in the distance, to the fox’s many leaps? reencoding in figure 1b. source maps consistently and unique- What to its fatigue or its giving up on Now let us examine the basis for ly to an element in the target” (p. the grapes? What to the long snout, the mapping that ACME eventually 31). The critical passage that jolted reddish fur, bushy tail, brown soil, finds—namely, S (for Saddam) onto

76 AI MAGAZINE Book Review

of creative analogy! Indeed, Holyoak a and Thagard say that semantic simi- Pre–Gulf War Pre–World War II larity also plays a role in guiding the president-of (Saddam, Iraq) führer-of (Hitler, Germany) choice of mapping. To illustrate this invade (Iraq, Kuwait) occupy (Germany, Austria) concept, figure 2b depicts another pair of situations. ACME sees this analogy as stronger b than the arithmetic analogy—if in- Pre–Gulf War Pre–World War II formed ahead of time that president- p (S, I) f (H, G) of and conductor-of are semantically i (I, K) o (G, A) similar, as are invade and march-onto. Unfortunately, though, the filing on- to a stage by the members of an or- Figure 1. chestra hardly seems analogous to the invasion of one country by an- other. Even though the mapping has a both structural and semantic under- Pre–Gulf War Arithmetic pinnings, it falls flat to a human. president-of (Saddam, Iraq) greater-than (5, 2) What’s missing? invade (Iraq, Kuwait) twice (2, 1) Following Holyoak and Thagard’s lead, let us go back to the theme song of causality. They point out (p. 250) b that Iraq invaded Kuwait because Pre–Gulf War Pre–1812 Overture Saddam was Iraq’s president and sug- president-of (Saddam, Iraq) conductor-of (G-Szell, Cleve-orch) gest that such flows of causality play nvade (Iraq, Kuwait) march-onto (Cleve-orch, Symph-Hall-stage) a central role in the pre–Gulf War/pre–World War II analogy. If we were to add a new line to this effect Figure 2. on the left side, and on the right side we also added a line to the effect that H (for Hitler), and so on. The crux of I <=> G Szell, as leader, had planned the con- ACME is a parallel-processing connec- S <=> H cert, ACME would glow with content- tionistic tussle among all allowable K <=> A ment at this mapping between high- mappings, “allowable” here meaning p <=> f er-level relations, much as SME glowed that lowercase letters (predicates) can i <=> o over finding the two ands that sup- map only onto other lowercase letters Structural similarities of the sort posedly lay at the core of a deep anal- and, similarly, for uppercase letters just shown play the starring role in ogy. Yet, even the parallelism of (objects). Thus, S might map onto H, ACME’s mapping process. However, causalities doesn’t make the analogy G, or A, as might I and K. In fact, all note how little the mapping found seem much more insightful than the these hypotheses, silly or not, will be has to do with aggressive invasions or arithmetic one. The reason is simple manufactured and entertained by ambitious dictators—all that was but worrisome: ACME discovers this ACME. However, notice that only one needed for ACME to find it was that analogy without having an inkling of uppercase letter occurs twice inside each “war prelude” consisted of two what orchestras do, what countries the Gulf War formulas (I), and lucki- predicates of order two and that the are, what people are—or even what ly, there is just one uppercase letter first argument of one was the same as an event or a cause is. that occurs twice inside the World the second argument of the other. To An ACME supporter might object: War II formulas as well (G). This re- make the program’s dependence on “This is unfair—a crucial part of the sult gives a great big boost to the ob- pure syntactic similarity a little clear- difference between the two situations ject–object mapping I <=> G. er, look at the display in fiigure 2a. has been left out! Kuwait didn’t want Notice now that I occurs as the sec- Based on just the same structural sim- to be invaded, whereas the audience ond argument of the Gulf War predi- ilarities, a pre–Gulf War/arithmetic was looking forward to the orchestra’s cate p and that G likewise occurs as analogy can be discovered, with “2” entrance!” Quite true, but notice that the second argument of the World mapping to “Iraq,” “5” to “Saddam,” this objection shifts the discussion War II predicate f. This second clue, “twice” to “invade,” and so on. Al- from how mapping is done to what combined with the I <=> G hypothe- though this analogy could be claimed ought to have been encoded in formu- sis, tips ACME off to the plausibility of to be a cross-domain mental las and given to ACME. In other words, mapping p onto f. Given these guess- leap—the Holyoak and Thagard it points straight at the gaping hole in es, a mechanical process of elimina- grail—it is less than impressive. Sure- the entire approach: There is no gist tion hands the rest to ACME: ly, more must be involved in a theory extraction, no sense for essence.

FALL 1995 77 Book Review

One could, of course, add more dike between “Vietnam” and “viet- wants to be accused of falling for or lines to both sides to make the nam-of,” and the consequent sloshing promulgating, although probably all pre–Gulf War/pre–1812 Overture back and forth among objects, at- of us do to some extent. In Holyoak mapping appeal less to ACME. Such tributes, and so on, practically defines and Thagard’s case, they have man- patch ups can always be done a pos- the fluidity of human thought. aged to convince themselves, and teriori to enhance analogies one In a way, Holyoak and Thagard’s hope to convince others, that their hopes for and hinder undesirable own nonchalant sloshing back and program makes analogies between ones. However, adding lines made of forth between full real-world situa- Saddam and Hitler, between solar sys- vacuous symbols won’t ever impart tions and their tiny gists epitomizes tems and atoms, between Socrates and understanding to ACME because it was what I am talking about: It is the hu- a midwife, between Hamlet and King made only to map sets of formulas man mind at its most fluid. Unfortu- Lear. Given such ostensible successes, onto each other, not to understand nately, our mental fluidity, although they would naturally be unreceptive to any insinuation that their model situations. ACME is not—and never responsible for our best insights and could have omitted something critical was intended as—a model of the most creative findings, often leads us about analogy making and loath to “sense for essence.” And that is most into deep confusions as well. To consider the suggestion that the true unfortunate because a sense for conflate one’s understanding of an Ae- crux of analogy making—including essence is truly the essence of sense. sop’s fable with a few abstractions gist extraction and active concepts— The entire discussion of analogy in forming its core, or worse, with a few might be studied more fruitfully in a this book rests on an ironclad distinc- carefully chosen lines of predicate cal- well-designed microworld. Regret- tion between “objects,” “attributes,” culus, is just such a confusion. Anoth- tably, Holyoak and Thagard have bought into today’s collective wisdom that shuns microworlds as outmoded Many AI researchers, in their haste to reach what and irrelevant to modeling . passes for real-world performance, settle for surface-level Anyway, whatever modest successes one might have in a microworld, how appearance and sweep deep issues under the rug. much grander to be able to say that one’s program had, on its own, dis- covered the analogy between West “relations,” and so on. AI researchers er such confusion is the complete Side Story and Romeo and Juliet! And so, are, of course, free to erect rigid walls omission from a computer model of real world, ho! anywhere they want in their comput- analogy making of any model of ac- However, Holyoak and Thagard’s er code, but in a human mind, such tive concepts—that is, a model of how way of computationally modeling re- distinctions are anything but iron- concepts in long-term memory can al-world analogy making is, before the clad. Hitler, for example, was the one tentatively be recognized in a situa- computer is even plugged in, to hand and only Führer of Germany. For this tion, activated to various degrees, and shrink each real-world situation into a reason, we humans experience a pro- selectively promoted from long-term tiny, frozen caricature of itself, con- found blur between the role “Führer” memory into working memory to taining precisely its core and little and the filler “Hitler.” As Gilles Fau- serve as constituents of fluid, hierar- else. Only then does the computer en- connier has documented so exten- chical representational structures. To ter the picture, mechanically convert- sively in his book Mental Spaces (MIT my mind, trying to develop a theory ing the two frozen representations in Press, 1985), role-filler blurs are ubiq- of analogy making while bypassing to a highly overpopulated con- uitous in human thought and per- both gist extraction and the nature of nectionist network, most of whose vade human language. But the ACME concepts is as utterly misguided as nodes represent mappings so silly that model would forbid, every bit as trying to develop a theory of musical a human mind would never consider rigidly as arithmetic forbids multiply- esthetics while omitting all mention them, and then performing a kind of ing an equals sign by the integer 7, of both melody and harmony. relaxation process in which the net- the mapping of the predicate führer-of Probably the reason for these ma- work sighs and settles down into an onto the object Saddam. However, the jor gaps in Holyoak and Thagard’s equilibrium. During this slow sagging analogy “Saddam is the Hitler of Iraq” approach is that like so many others process, no fresh new concepts or slides the object Hitler into a predicate in AI, they are eager to tackle the real ideas can possibly enter the characteri- hitler-of—a role that the object Sad- world—too eager. Many AI re- zation of either situation; in fact, dam can fill. In a human mind, a role- searchers, in their haste to reach nothing changes at all except for nu- filler blur will ensue, much as Viet- what passes for real-world perfor- meric values on nodes, the biggest of nam turned into a category about mance, settle for surface-level appear- which tells what seems to match which one could cry “No more Viet- ance and sweep deep issues under the what. What emerges at the end of this nams!” or even assert “Cambodia is rug. In so doing, the researchers dull, unconscious sagging is an analo- the Vietnam of Vietnam.” A mind themselves fall victim to the ELIZA ef- gy—or, rather, a match up between erects no watertight object-relation fect, something that nobody in AI certain Lisp atoms.

78 AI MAGAZINE Book Review

At this point, the tiny, inert predi- the objective, metalevel judge, using the very concept of sameness! cate calculus cores are conflated with John Searle’s famous Chinese-room Chapter 4, on analogy making in the original full-blown situations, scenario as their prime example of a children, reports on many ingenious subtly leading many intelligent peo- flawed intuition pump, which it cer- and astonishing experiments. My fa- ple to such happy conclusions as that tainly is, and pointing out its flaws. vorites, done by psychologist Judy the program has insightfully leaped (Ironically, on the very next page, DeLoache and colleagues, revealed a to a cross-domain analogy, that it has they voice pessimism about the possi- deep mental breach between 2- used semantics and purpose in set- bility of there ever being an objective 1/2–year olds and 3-year olds. Her tling on its mappings, that it has un- way to evaluate intuition pumps. first experiment showed that 3-year derstood how Socrates coaxes ideas This is what I meant by “waffling.”) A olds, if they saw an adult hiding “Lit- from students much as a midwife fourth arena where they show respect tle Snoopy” behind or under toy fur- helps bring babies into the world, for detachment and unbiasedness in niture in a small-scale model of a and so on. However, as the mappings analogy making is politics, illustrated room and then were taken to the full- of “Iraq” onto “2” and “Cleveland-or- by their high praise for George Ball, sized room and asked to find “Big chestra” reveal, ACME, despite its cre- who saw more deeply than others in- Snoopy,” would generally make a ators’ wishes and claims, functions in to the Vietnam situation. beeline for “the same place” and find a microworld; it’s just a microworld I would certainly agree that most it. The younger children, by contrast, whose sparseness is disguised by a pa- human analogy making is highly could almost never do such a map- per-thin facade of real-world terms. biased. For this reason, anyone who ping. They couldn’t go from one do- Alas, for numerous reasons, anemic wants to study analogy making in its main to the other. However, De- microworlds posing as rich macro- full glory and squalor will have to Loache’s next experiment showed worlds are par for the course in most consider all its flaws, a major one of something amazing: If these younger of AI today. Deep and facadeless mi- which is bias, whether conscious or children were tricked into thinking croworld projects such as the ancient unconscious. But many of us strive, that the experimenters had a “size- SHRDLU seem rare as hen’s teeth. as does an arbitrator, a judge, or a sci- changing machine” that could make A key premise of Mental Leaps is entist, after unbiased, purpose-inde- a puppet or a dollhouse room double that purpose is indispensable to anal- pendent insights, and it is this quest in size, they would have no trouble ogy making. In Holyoak and Tha- for objectivity, this attempt to banish finding “the same place” in a suppos- gard’s theory, purpose seems to play purpose from one’s analogies, that edly enlarged room that was magical- the dubious role that spin plays in Holyoak and Thagard seem to have a ly made by the machine, right before politics and the law, serving merely hard time reconciling with their their innocent eyes, from a small to distort various aspects of a situa- stress on the indispensability of room. In other words, as long as 2- tion, trying to get people to see purpose, with all the subjectivity and 1/2–year olds thought they were deal- things in a particular way. As I see it, intellectual relativism that it implies. ing with a single room at different the authors waffle about purpose, If I have been harsh on this book, sizes and, thus, didn’t need to make a sometimes doing their best to show it is because it is so pervaded by the mapping from one room to another, how central a role it plays, other authors’ computer-modeling ap- they effortlessly found the toy, but times implying that purpose-free proach, with which I obviously dis- when the search task seemed to in- analogies are the best of all. agree on many levels. However, the volve two different rooms, thus re- In several different contexts in book was extremely engrossing and quiring the mental building of a Chapters 6 and 7, they reveal admira- gave me many new insights about room–room mapping, they failed. tion for the impartial, wise figure how the mechanisms for analogical These and other wonderful experi- who objectively chooses between ri- thinking evolved over eons, develop ments on children’s thinking are ex- val analogies proposed by purpose- in each of us as we grow, and func- cellently described, and even if one driven, hence biased, parties. One tion in real time as we strive to deal balks at some of the notions and no- context they describe is law, where a with life’s imponderables. tations used in the discussions, there judge evaluates the merits of different Chapter 3, for example, about anal- is no doubt that deep revelations precedents proposed by opposing ogy making by apes, was most reward- about the human mind are being pre- lawyers. Another context is baseball, ing. The crucial idea of a ladder of lev- sented, and presented in a lively, en- where a neutral arbitrator sets play- els of understanding of the abstract gaging way. ers’ salaries by choosing between ri- notion of sameness, although I could Chapter 8 is a stimulating one— val analogies proposed by the player quibble with some of the distinctions, mostly on analogy in scientific dis- and the team. A third such context is is well charted. In particular, there is a covery, technological innovation, philosophical argumentation, where long discussion of the degree to which and teaching—but even better is analogies called intuition pumps are the chimpanzee Sarah’s ability to Chapter 9, much of which concerns proposed by philosophers to get peo- make certain fairly abstract analogies metaphor. Perhaps my enthusiam is ple to see abstract issues in a particu- was a consequence of her having been predictable because metaphor is an lar, biased way. Here, Holyoak and trained linguistically and, in particu- area so cloudy and complex that Thagard themselves play the role of lar, of her having learned a symbol for Holyoak and Thagard don’t try to

FALL 1995 79 Book Review shoehorn everything into the terms of their own theory. Rather, they are Android Epistemology fully cognizant of the magnitude of the barrier and welcome it as a chal- Edited by Kenneth M. Ford, Clark Glymour, & Patrick J. Hayes lenge. Most surprising to me was that in discussing the metaphor “Socrates Published by the AAAI Press / The MIT Press as a midwife of ideas” (pp. 219–220), 336 pp., $25.00 cloth, ISBN 0-262-06184-8 they back away from their usual pre- fabricated-gist approach (although pistemology has traditionally been the study of human knowledge and rational they offer no alternative to it). In- change of human belief. Android epistemology is the exploration of the space of deed, in their excellent discussion of Epossible machines and their capacities for knowledge, beliefs, attitudes, desires, analogy, metonymy, and metaphor, and action in accord with their mental states. From the perspective of android epistemol- they verge on the emerging notions ogy, artificial intelligence and computational cognitive psychology form a unified en- of frame blending and blended deavor: artificial intelligence explores any possible way of engineering machines with in- spaces, which I think are promising telligent features, while cognitive psychology focuses on reverse engineering the most and important and will offer a new intelligent system we know, us. The editors argue that contemporary android epistemolo- view of analogy as part of a much gy is the fruition of a long tradition in philosophical theories of knowledge and mind. more comprehensive theory of hu- man understanding. In this, I am The sixteen essays by computer scientists and philosophers collected in this volume in- happy to say, I find exciting conver- clude substantial contributions to android epistemology, as well as examinations, defens- gences between the thinking of es, elaborations, and challenges to the very idea. Holyoak and Thagard, the ideas of linguists Gilles Fauconnier, George Lakoff, and Mark Turner, and my Contents own thoughts, among others. Slowly ■ The Prehistory of Android Epistemology / Clark Glymour, Kenneth Ford, but surely, the centrality and ubiqui- & Patrick Hayes ty of analogy and metaphor in the human mind are being revealed, ■ Machine as Mind / Herbert A. Simon thanks to such work. ■ The Vitalists' Last Stand / Anatol Rapoport Although most of this book is com- mitted to an impossibly rigid and im- ■ Could a Robot Be Creative--And Would We Know? / Margaret A. Boden plausible theory of analogy making, ■ From Cognitive Systems to Persons / Antoni Gomila it manages to survey analogical thinking in a remarkably thorough ■ Could, How Could We Tell if, and Why Should, Androids Have Inner Lives? / way, make clear its place and power Selmer Bringsjord in cognition, and pinpoint many of the most perplexing issues about ■ Android Epistemology: An Essay on Interpretation and Intentionality / analogy. The authors are to be saluted Kalyan Shankar Basu for their impressive bringing together ■ Taking Embodiment Seriously: Nonconceptual Content and Robotics / of so many ideas from so many Ronald L. Chrisley sources, and it is to be hoped that in their next book on analogy, they will ■ Imagination and Situated Cognition / Lynn Andrea Stein have moved beyond the seriously ■ Towards Constructivist Unification of Machine Learning and Parallel Distributed flawed tacit assumptions that kept Processing / Chris Stary and Markus F. Peschl this book from becoming all it could and truly should have been. ■ Towards A Sentential ‘Reality’ for the Android / Cary G. deBessonet

Douglas Hofstadter is on the faculty ■ Towards the Ethical Robot / James Gips at Indiana University, where he is ■ The Ethics of Autonomous Learning Systems / A. F. Umar Khan College of Arts and Sciences professor of cognitive science and computer sci- ■ How to Settle an Argument / Henry E. Kyburg, Jr. ence. He directs the Center for Re- ■ Machine Stereopsis: A Feedforward Network for Fast Stereo Vision with Movable search on Concepts and Cognition Fusion Plane / Paul M. Churchland and is the author of numerous books and papers, including Gödel, Escher, ■ Alienable Rights / Marvin Minsky Bach: an Eternal Golden Braid (Basic Books, 1979) and, most recently, Fluid To order, call toll free 1-800-356-0343 (US & Canada) or (617) 625-8569, MasterCard & Concepts and Creative Analogies (Basic VISA accepted. Prices will be higher outside the US and are subject to change without Books, 1995). notice. Visit the AAAI Press website! http://www.aaai.org/Publications/Press/press.html

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