Kittay also explains that there may exist �bridge� terms, which influence the interpretation of the correct application of the focal term (1987, 165�66). For example, if the field of the text provides a topic that is to convey a metaphorical use of the word seal, cognitive selection would eliminate the semantic connotation of seal as used to apply to important documents if bridge terms such as �clever tricks� or �waddling walk� were found within the frame of the metaphor. The mammal and its linguistic connotations would then be cognitively retrieved for the eventual juxtaposition of semantic references.
The field of the vehicle in a metaphor takes on the role of the originating field, according to Kittay. This provides for the asymmetrical analogies of metaphorical extension: �one side of the analogy has privileged status in regard to the other� (1987, 152). It is this originating (vehicle) source that produces and generates the relevant contrasts in the metaphor. However, only some, but not all, relations of contrast are mapped onto the semantic field of the topic of the metaphor.
Metaphors change language. According to Mac Cormac, metaphors operate as cognitive processes that produce new insights (1985, 2). Mac Cormac sees the creator of metaphor as retrieving and mapping long-term memory combinations of words that are not normally associated (1985, 129). The resulting similarities, as well as dissimilarities, then generate new meanings. Comprehension of these new meanings depends on whether the receiver involved can see the connection between the two concepts associated in this unusual juxtaposition.
People do not intentionally create false statements as a way to express concepts in ordinary language production. They do not present nonliteral statements with the devious intention of providing falsehoods when describing something. Metaphors, however untrue they may seem when examined literally, are intended to enlighten, not to deceive. Yet philosophers have long been concerned with the mercurial quality of metaphors and their ability to confuse the issue of truth. In fact, some theories of metaphor were created in part as an attempt to resolve this issue.
As an example, the controversion theory, developed by Beardsley (1976), allows for metaphors to collapse into analogies in order to prevent deviancy from the truth. Converting a metaphor to a simile through the use of the terms like or as if might reduce the element of falsehood, but it would also stifle the creative intent conveyed by the metaphor in the first place.
Kittay (1987) contends that metaphors do more than compare two concepts. A literal comparison, perhaps of schools and libraries, or of grapes and squash, may compare set categories of similar institutions or foods. A metaphor, however, crosses domains of categories. Metaphors create similarity by referring to concepts in different categorical boundaries�for example, comparing grapes and libraries. The different referents of a metaphor, coming from two distinct categories, exert a tension that generates a new meaning (183). Metaphors help us to assimilate information already within our conceptual organization. Kittay says, �The cognitive force of metaphor comes, not from providing new information about the world, rather from a (re)conceptualization of information that is already available to us� (39).