How Far Can We Go with Reason?

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solve many problems facing link between fecal contamthe world. ination of drinking water Historically, the study of and outbreaks of cholera. reasoning has not been at the His account of deductive center of psychology in geninferences is more comReferences eral or of cognitive psychology pelling than his account 1. R. S. Lynd, H. M. Lynd, Middletown: A Study in in particular. There are far of inductive and creative Contemporary American Culture (Harcourt, Brace, New more cognitive psychologists processes. Although his York, 1929). studying perception and membroad characterizations are 2. R. S. Lynd, H. M. Lynd, Middletown in Transition: A Study in Cultural Conflicts (Harcourt, Brace, New York, 1937). ory. Johnson-Laird has strived useful, he does not really 3. A. C. Kinsey, W. B. Pomeroy, C. E. Martin, Sexual throughout his career—at solve or even address, for Behavior in the Human Male (Saunders, Philadelphia, the University of Sussex, the example, the crucial prob1948). Medical Research Council lem of creativity: How do 4. A. C. Kinsey et al., Sexual Behavior in the Human Female (Saunders, Philadelphia, 1953). Applied Psychology Unit in Thinker on a Rock (Barry Flanagan, we generate novel ideas in Cambridge, and now Princeton 1997). the first place? His theory 10.1126/science.1140764 University—to raise the prois better at characterizing file of the study of reasoning. He has been at how we assess whether our ideas are PSYCHOLOGY least somewhat successful. He, his students, good ideas. and his collaborators have received interThe author believes his theory of mental national recognition for their work. models would characterize thinking in the Four big questions arise from the book. humanities and arts as well. That is a leap of First, to what extent does Johnson-Laird suc- faith on his part and would be a bigger leap ceed in describing how we reason? Second, to on the part of a reader. There is no eviwhat extent do the reasoning structures (men- dence—at least in the book (at its end, Robert J. Sternberg tal models) Johnson-Laird posits characterize Johnson-Laird acknowledges that his case ust as its name implies, How We Reason is scientific reasoning, a major focus of the histories include nothing from these nominally about how we reason. Its not- book? Third, to what extent does reasoning fields)—that this is the case. Lastly, How We Reason is at its weakest in so-hidden agenda is actually quite a bit account for the kinds of thinking artists, writbroader: namely, to argue that reasoning can ers, composers, and others in the humanities showing how Johnson-Laird’s model of reahelp people lead successful lives and that to and arts use in their work? Finally, how much soning—or, really, any model—applies to help is reasoning of the kind everyday life. If you want to know how to the extent that people fail, it described by Johnson-Laird to us solve the problems of what to do about the is in part because emotions How We Reason all in our everyday lives? intervention in Iraq, runaway government begin to color their reasoning. by Philip N. Johnson-Laird With regard to how we reason, spending, or a failing marriage, you probably Beyond establishing the imOxford University Press, Johnson-Laird’s account may not will find little in this book to help. Johnsonportance of reasoning, Philip Oxford, 2006. 583 pp. be entirely correct, and it is cer- Laird believes that many of the world’s ills are Johnson-Laird contends that $57.50, £29.95. ISBN tainly not complete. To give two caused by emotional contamination of reasonreasoning can be understood 9780198569763. examples: Expert reasoning prob- ing, an idea that goes back to some of the earin terms of his theory of menably relies more on pattern recog- liest theorists (4). He tends to view emotion as tal models—according to which people, in the reasoning process, nition than would follow from mental models. the cause of failings in reasoning. Yet, one manipulate abstract mental representations And the fundamental problem of induction— might instead argue that emotion is what why we make certain inductions but not oth- makes the world run round. If we want to that allow them to reach conclusions. Johnson-Laird burst upon the cognitive- ers—is scarcely addressed. But no other understand how to rectify our own, and the psychology scene with the publication of current theory of reasoning is complete either. world’s, problems, we had better understand Not that many years ago, students were emotional reasoning in its own right, rather Psychology of Reasoning (1). That book was fairly narrowly focused, primarily on deduc- being taught, for example, that syllogisms than simply label it as an aberration. Twotive reasoning. A later book (2) sought to char- were solved by heuristics, such as atmosphere process theories of reasoning (5), which posit acterize reasoning as well as other cognitive (if there is a negation in a premise, the solution an experiential, a-rational system, as well as processes in terms of mental models. The cur- involves a negation; if there is a particular, the the more rational one of which Johnson-Laird rent magnum opus goes quite a bit beyond its solution involves a particular) or conversion writes, seem a large step toward that goal. predecessors in dealing with problems of (people read “If A, then B” as equivalent to “If References induction, creativity, and insight. In past work, B, then A”). Considering how woefully inade1. P. C. Wason, P. N. Johnson-Laird, Psychology of Reasoning: Johnson-Laird has devoted quite a bit of effort quate these past accounts were, JohnsonStructure and Content (Batsford, London, 1972). to battling the theories of his competitors, such Laird has brought us very far along in under2. P. N. Johnson-Laird, Mental Models: Towards a Cognitive Science of Language, Inference, and Consciousness as Lance Rips (3). In this book, Johnson- standing how we reason. (Harvard Univ. Press, Cambridge, MA, 1983). Johnson-Laird gives fascinating accounts Laird’s goal is not so much to fight the oppo3. L. J. Rips, The Psychology of Proof (MIT Press, Cambridge, sition but to argue that human reason can of some major examples of scientific reasonMA, 1994). 4. R. J. Woodworth, S. B. Sells, J. Exp. Psychol. 18, 451 ing, such as the Wright brothers’ designing of (1935). the first successful airplane, how the codes 5. S. A. Sloman, Psychol. Bull. 119, 3 (1996). The reviewer is at the School of Arts and Sciences, Bailou underlying the Nazi Enigma machine were Hall, Tufts University, Medford, MA 02155, USA. E-mail: 10.1126/science.1140812 broken, and how John Snow discovered the [email protected]

How Far Can We Go with Reason?

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30 MARCH 2007

VOL 315

SCIENCE

Published by AAAS

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