2.5 METAPHOR AND ANALOGY
From Aristotle to Cicero to Quintilian, the earliest treatments of metaphor put similarity at the heart of the phenomenon, but agree on no single approach to formalizing similarity. Recall that Aristotle’s four-fold scheme posits three ways in which inter-category similarity can be used to form a metaphor (strategies (a) to (c)) and a single way in which analogical similarity can be used (strategy (d)). Yet these strategies are not claimed to be mutually exclusive, and so, we can imagine a metaphor simultaneously exploiting both categorization and analogy together. It is thus useful to see the metaphor “marriage is slavery” as both a categorization statement (putting marriage in the same category of unpleasant situations as slavery) and as an analogy (so husbands are to wives, or wives are to husbands, as owners are to slaves). Yet the dichotomy between, on one hand, similarity arising from shared category membership, and on the other, similarity based on analogical proportion, is one that still separates modern theories of metaphor production and interpretation.
Aristotle’s category membership approach survives, in a more finessed form, in Glucksberg’s [1998, 2008] category inclusion view of metaphor. Whereas Aristotle’s scheme (c)—in which the name of one species is applied to another of the same genus—presumes that source and target share a pre-existing membership in a common genus, Glucksberg argues this sharing is a result of the metaphor and not a cause. Moreover, since the Aristotelian scheme is easily trivialized when applied within a well-connected category hierarchy that ultimately places every concept under an all-embracing category root, Glucksberg’s category inclusion view argues that the source and target categories cannot simply share, or be made to share, just any genus category. The point of metaphor, after all, is not just to assert that two ideas happen to share a common category; at the very least, a metaphor must also suggest a means of naming the specific category that the speaker has in mind. For Glucksberg, then, the source of a metaphor does not so much represent itself but the broader category of which it is a highly representative member. As such, “slavery” does not literally denote either the legal or historical sense of slavery in the metaphor “marriage is slavery,” but any institutionalized system of exploitation and oppression. In contrast to the classical view of categorization, which models categories as simple mathematical sets, modern cognitive psychologists adopt a textured view of category structure in which some members are more central than others. The most central members may be so associated with a category—such as shark and wolf for the category of ruthless predators, jail for oppressive and confining situations, slavery for cruel and exploitative relationships—that they offer a more evocative, concise, and convenient way of naming that category than any literal alternative.
Yet Aristotle’s strategy (d), analogical proportion, suggests how we might side-step this search for a mediating category altogether. For there is no need to find a common genus to unite the source and the target if the two can be reconciled by means of direct, unmediated relational similarities. By this reckoning, metaphors are made from the same stuff as scientific analogies: one observes a pattern of relationships in one domain, the tenor or target domain, and is reminded of a parallel set of relationships in another, the vehicle or source domain. But, as argued by the structure-mapping school of analogy [Gentner, 1983], a good analogy is more than a set of observed correspondences between domains. Rather, these correspondences—systematically linking two different conceptual structures—are just the starting point of an analogy. Having anchored elements of the source domain to the target domain, these correspondences then guide the transfer of additional material from the source into the target. For example, the Bohr/Rutherford analogy of atomic structure views the nucleus of the atom as occupying a relationally parallel position to the sun in a solar system, so that the electrons that orbit around the nucleus are the nanoscopic equivalent of the planets that orbit around the sun. Having established these correspondences, the analogy can now suggest a causal explanation for the orbit of electrons, by importing the causal explanation for the orbit of planets around a sun: for, just as the sun keeps speeding planets in orbit via a cosmic force, gravity, a comparable force must be attracting speeding electrons to stay in orbit around a nucleus. Gentner argues that many metaphors also work in this way: a source is chosen because of its analogical parallels to the target, and because it contains additional conceptual material that a speaker also wishes to assert of the target. A listener unpacks the metaphor by uncovering much the same parallels, and by then using these as a guide to the transfer of additional material from the source.
Consider again the metaphor “marriage is slavery.” A systematic analogy between marriage and slavery will identify abusive behaviors in both domains and create mappings between the protagonists and agonists of these behaviors. Thus, abusive husbands may be slave-owners and abused wives their slaves, while matchmakers can be mapped to slave dealers, family homes to plantations, wedding rings to shackles, marriage licenses to ownership papers, etc. A particular mapping is systematic if its elements are well-connected to each other, especially if they are connected via parallel causal relationships that explain how the various parts of a domain influence other parts of the same domain. Having established correspondences between ideas in the source and target domains, an analogy can now transplant onto the target any relationships that link these ideas in the source domain, to provide new insights as to the cause of these behaviors in the target domain. For instance, slave owners beat their slaves while abusive husbands beat their wives. But slave owners beat their slaves because they believe they own them, and see them as mere physical objects to mistreat as they see fit. By analogy, abusive husbands may beat their wives because they, too, believe they own them, and because they, too, view them as mere physical objects.
Any model of metaphor that hinges on the identification of a common genus, whether it has the simplicity of Aristotle’s earliest scheme or the sophistication of Glucksberg’s category inclusion model, operates by reducing the specific to the generic. Such approaches are best suited to the generation and interpretation of familiar metaphors, or to apparently novel metaphors that dress up old conceits in new ways. In contrast, the structure-mapping approach does not aim to see, or need to see, the generic in the specific, and so, ceteris paribus, is just as capable of seeing the analogical proportions between the source and target ideas of a truly original metaphor as it is for those of a wholly conventional pairing. However, this also means that the analogical approach will fail to capture the sense of familiarity that one experiences when faced with a timeworn combination of ideas, just as it must fail to capture the thrill that accompanies a truly original pairing. Of course, even the most hackneyed metaphor was once fresh and novel, and, although time does not change the substance of our metaphors, it does change the way we see them, and perhaps even the way we process them.
With two alternate approaches to choose from, each of which is better suited to a different kind, or historical stage, of metaphor, it makes sense to view these not as competing but as complementary approaches. As proposed by Bowdle and Gentner [2005] in their career of metaphor hypothesis, fresh metaphors that do not obviously instantiate a familiar conceit are more naturally understood as analogies. Structure-mapping analysis allows listeners to identify the parallel relationships in source and target domains that contribute to a new metaphor, thus allowing them to abstract from the source those parts of its meaning that are most likely to contribute to other metaphors. As speakers become habituated to a given metaphor, and to other metaphors that use the same source for similar ends, they come to think of the source as a vehicle for those parts of its conceptual structure that are transferable across domains. In effect, they form an abstracted representation of the source that ultimately allows the metaphor, and similar metaphors with the same source, to be understood in category inclusion terms.
The earliest account of metaphor, as offered by Aristotle, acknowledges that metaphor is a complex