How and why does a metaphor work? What happens to us when we hear or read one? My guess is that a metaphor, because it is an erroneous statement, conflicts with our expectations. It releases, triggers, and stimulates our predisposition to detect error and to take corrective action. We do not dismiss or reject a metaphor as simply a false statement for we recognize it as a metaphor and know as [Donald] Davidson suggests that it alludes to something else that (...) we might wish to notice. It preempts our attention and propels us on a quest for the underlying truth. We are launched into a creative, inventive, pleasurable act. To turn Piaget around, to invent is to understand. For the hearer or reader of a metaphor to detect, by himself, the nature of the error and to invent his own version of the truth entails understanding and achievement and thus pleasure. Such pleasure perhaps owes its origin to, and is enhanced by an echo from, the metaphoric playfulness of childhood. A metaphor is a peremptory invitation to discovery. What is discoverable are the various allusive ties, or common attributes, between the metaphor and the underlying truth to which it points. It is plausible to guess that the pleasure, and hence power, of the metaphor depends on two factors. It is the more powerful and effective the greater the number of allusive ties discovered and the greater the speed or suddenness with which the discoveries are made. A metaphor that packs all of its allusions into one or a few words should be more effective than a metaphor on which the same allusions are scattered throughout a long chain of words or sentences. The number of allusive ties in some sense reflects how close the metaphor approaches the truth—how near it is to being on target. Perhaps the closer it is, the more compelling the urge to correct the error—like the pull of a magnet. Don R. Swanson is professor and dean of the graduate library school at the University of Chicago. (shrink)