The study of the use of metaphor in literature has a much longer tradition than the cognitive linguistic approach to this subject and therefore it ought not to be surprising that literary scholars have developed their own terminology to describe various phenomena, including metaphors. However, the influence of cognitive linguistics on other fields of inquiry has been so immense that cognitive linguistic terminology has became more and more frequently used. Thus, nowadays both terminologies are acknowledged as equally valid, but that may well cause some confusion as sometimes there are now several different terms to refer to one thing.
In cognitive linguistics there is the distinction between the ‘source’ and the ‘target’ domains. The source domain incorporates metaphorically used concepts, while the target domain includes concepts used non-metaphorically. Those terms are sometimes used interchangeably with those introduced by literary studies scholars, namely ‘vehicle’ which in cognitive linguistic theory is called ‘source domain’ and ‘tenor’ – the ‘target domain’. Still another tradition of description of metaphors has a different terminology and thus the ‘source domain’ can be called ‘focus’ and the ‘target domain’ might be referred to as ‘frame’ (Steen, 2005:53).
The classification of metaphors as seen by cognitive linguists has been presented above and as it has been said, it also influenced literary studies. However, there are certain differences, or to put it another way, some additional types of metaphor can be found in literature, whether fulfilling the role of rhetorical device or not. Among them Leech cites four types of functional roles for metaphors. he defines them as follows: (Leech, 1991:158):
One more metaphor type is an extended metaphor which is usually formed by numerous different figurative phrases, and which stretches throughout several lines of poetry, or over a few sentences in prose. Still another type of metaphor, which is to be found in literature is, as Leech (1991:160) says, a compound metaphor. According to this scholar, a compound metaphor is one that comprises of the overlapping of two or more different metaphorical phrases. Moreover, even larger than extended metaphors are so called megametaphors. As Stockwell (2002:111) puts it, megametaphors are metaphors which recur throughout the text “often at pivotal moments and often in the form of thematically significant extended metaphors”. What is more, Stockwell compares megametaphors with micrometaphors, which according to him are “specific realizations of the numerous metaphors that occur in the text and that accumulate into the sense of a megametaphor” (Stockwell, 2002:111).
In various types of texts or for stylistic purposes the above mentioned metaphors and metaphorical expressions may take different forms. Some of the representations of metaphorical phrases at first sight do not even resemble metaphors and only after a thorough analysis can they be properly understood. Stockwell presents various interesting realizations of the metaphor BRAIN IS A CITY in the following examples (Stockwell, 2002:107). His categorization reflects a variety of traditional categories as well as syntactic ones. Thus he groups simile, analogy and extended metaphor into a single group. Then he highlights copula constructions, appositional patterns, partitive and genitive expressions, adjective plus noun phrases, compounds and lexical blends, grammatical metaphor and sentence metaphor. He ends his list of metaphor categories with fiction and allegory. In a sense, one could say that Stockwell is still quite tied to syntax, but he has certainly shifted his stance toward a truly semantic view of things. His definitions of these categories are given in (32) (a-i) (Stockwell, 2002:107):
Although all of the above examples have their basis in the BRAIN IS A CITY metaphor they all portray the idea from different perspectives, thus making the readers perceive it in a slightly different manner. As there are practically no limits to the ways in which one metaphor may be represented in literature, it is often difficult to keep track of their use.