Metaphor's peculiar property to yield cognitive insight — often in otherwise false sentences — has been the focus of contemporary studies of metaphor. In Metaphor: Its Linguistic Structure and Cognitive Force, Kittay (1987) attempts to understand the cognitive force of metaphor by utilizing semantic field theory — a theory that assimilates conceptual structure to a semantic structure underlying the utterances we produce. According to semantic field theory, the meaning of a word is, in part, a function of its relation to words occupying the same conceptual terrain. For example, "red" takes its meaning, in part, from the other color terms in the language, terms with which it has the semantic relation of co-hyponym. Similarly, the meaning of "hot," is determined, in part, in contrast to other terms in a gradable antonymy, that is, in contrast to "cold," "warm," and "cool." The meaning of terms is also a function, in part, of the words with which they can collocate. For example, "fisherman" stands in the relation of AGENT to the verb "fish." That is, at least part of what it means to be a fisherman is to be one who engages in the action of fishing. Furthermore, semantic field theory proposes that the lexicon is organized along conceptual affinities and contrasts reflected in the semantic relations that structure fields.