or “like”—to the counterfactuality of a viewpoint. That is, every simile “A is like B” asserts not just that A is similar to B, but that A is very much not B. Finally, the similes not only explain the meaning of the metaphor, but offer a rationale for it too: the paraphrase suggests that the metaphor is the speaker’s way of making sense of the bad behavior of others.
The implicit negation in every simile makes simile a particularly good choice for paraphrasing a negative metaphor. For, just as explicit similes contain tacit negations, explicit negations often suggest tacit similes, especially when the negation emphasizes the figurative qualities of a descriptor. Since most negative metaphors are trivially true in a literal sense, insofar as the underlying positive metaphor is literally absurd, then each negative metaphor is also its own literal paraphrase. Thus, it really is the case that no man is an island; that your wife is not your maid; that your overbearing boss does not own you; that your college fund is not an ATM; etc. Yet there is more to a negative metaphor than the negation of an obvious falsehood. A negative metaphor is not so much a disavowal of an explicit metaphor, or of the tacit conceptual pact that it implies, as it is an explicit repudiation of someone else’s implicit simile. Why else would we need to say something that is so obviously true? So, the frustrated wife who cries at her boorish spouse “I am not your maid!” is in fact saying “Do not treat me like your maid!” The moody teenager who snaps at a concerned neighbor “You are not my father” is in fact saying “Stop acting like my father.” And the man who needs to be told that “No man is an island” is no doubt acting like someone who believes the opposite. Similes allow a speaker to be abundantly clear as to the perceptual foundations of a figurative viewpoint, and clear in ways that are hard to achieve in metaphor.
Giora et al. [2010] argue that negation, when used to convey such apparently obvious facts, is a metaphor-inducing operation. So, like metaphors and similes, negations of the false or the absurd are much more likely to activate the figurative aspects of a descriptor than any literal qualities. Metaphor involves highly selective inference (see Hobbs [1981]) and the assertion “I’m no Superman” selectively activates the qualities of the cultural icon (and very dense descriptor) Superman that are most often projected by a metaphor or a simile, such as strength, resilience, and speed, rather than any literal quality related to appearance (e.g., wearing a red cape, or red underwear on the outside) or behavior (e.g., fighting crime, working in disguise as a reporter, etc.). Precisely what these figurative qualities are for a given descriptor is something that one would have difficulty discerning from only metaphorical uses of the descriptor, as metaphors rarely make explicit the qualities that are projected onto the target. This brings us then to another aspect of similes that makes them so useful to the computational modeling of metaphor. Not only do similes explicitly mark their figurative status with “like” or “as,” and frequently indicate the perceptual roots of their viewpoint with qualifiers such as “act like,” “smell like,” “look like,” etc., they also often explicitly identify the qualities that are transferred from the source/vehicle to the target/tenor.
The scholar Quintilian saw the difference between metaphor and simile as the difference between an implicit and an explicit comparison. Not only does a simile mark the comparison between a comparandum and its comparatum, it may also provide a third element, a tertium, to state the reasons why both are seen as similar [Roberts, 2007]. In the English simile frame “X is as Y as Z” the tertium is given by the [Y] element, although a speaker may omit the tertium to say simply that “X is like Z.” But when the tertium is explicit, as it always is in “as-as” similes, a listener can acquire from the similes of others a sense of the properties of a [Z] that are most likely to be activated in a figurative comparison. In this way, similes become an important vector for the transmission of cultural knowledge via language; as Charles Dickens puts it in the opening page of A Christmas Carol, “the wisdom of our ancestors is in the simile.” Dickens was referring to the swirl of stock similes that were common currency in the language and culture of his day, but the modern scholar, or modern NLP system, now has access to a long-tail of diverse similes—and diverse tertia—for a wide range of useful descriptors on the Web. Consider again the dense descriptor Superman: a Google search for the phrasal query “as * as Superman” (here * denotes a wildcard that can match any token in a text) returns web documents that fill the tertium * position with the following values: strong, powerful, fast, mighty, invulnerable, resilient, cool, and American. As these properties are frequently highlighted in figurative similes, it seems reasonable to assume that a metaphorical use of Superman will draw on the same properties.
The relationship between metaphor and simile is itself best described as a simile. Metaphor is like simile but it is not simile; nor is it wholly reducible to simile. Nonetheless, each concerns itself with the similarity of two ideas, and each focuses on qualities that readily extend across domains. So, just as similes can be used to make explicit the qualities that go unsaid in a metaphor, they can also be used to learn those very qualities, to provide—as we shall see later—the large set of dense descriptors that is required by any metaphor processing system.
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
