According to Robert B. Van Engen (2008), a metaphor is a multifaceted literary device that assists in illustrating complexity and in expressing clarity. It helps to compare the value of variables and to expose creativity. A metaphor is used in conversation to make it interesting. The American Heritage Dictionary of the English Language defined a metaphor as "a figure of speech in which a word or phrase that ordinarily designates one thing is used to designate another, thus making an implicit comparison."
Likewise, Aristotle considered metaphors a sign of language mastery and genius, but he also deemed them ornamental, appropriate for poetry but too enigmatic for philosophical or scientific discourse. On the contrary, Max Black articulated an influential alternative to traditional views of understanding metaphors. Having rejected Aristotle's comparison as too simplistic, Black argued that metaphor is a communicative phenomenon operating not at the level of mere word meaning, but at the (ostensibly) deeper level of conceptual structure. Lakoff and Johnson (1980) put forward that metaphors establish the modal method through which the mind represents concepts that are not sensorial or perceptual in nature. Their conclusion is:
"Metaphor pervades our normal conceptual system. Because so many of the concepts that are important to us are either abstract or not clearly delineated in our experience (the emotions, ideas, time) we need to get a grasp on them by means of other concepts that we understand in clearer terms (spatial orientation, objects). This need leads to metaphorical definition in our conceptual system" (1980, 115).
Conceptual Metaphor has been the prime concern for translation scholars, academicians, and students. Scholars have tried to map and analyze conceptual metaphorical aspects in poetry and novels for a long time. But somehow, they face a series of confusions regarding the meanings of some conceptual metaphorical phrases. As Newmark (1988) holds, whilst the central problem of translation is the overall choice of a translation method for a text, the most important particular problem is the translation of metaphor. Conceptual Metaphor is often fully employed in literary texts and it is regarded as a challenge to ESL students and academicians.
According to Tone Aksberg Bjerkmo Johansen (2007), the process that constitutes a conceptual metaphor is when the knowledge of one field is epitomized onto another field. Conceptual Metaphors are normally used when expressions that represent our thoughts in a conventional way are being systematically used in everyday language. An example of conceptual metaphor is a metaphoric concept such as "Theories are buildings," where we can partially conceptualize "Theories" in terms of "Buildings." According to Lakoff and Johnson, metaphor has the tendency to highlight and hide certain aspects of the target concept. Another example is "A relationship is a journey," which ascertains that the metaphor is measuring the progress in a relationship, but it does not give any idea of how this progress can be achieved. Metaphor is only a partial mapping as "not all the features of the source have analogs in the target,"
According to Apps (1995), metaphors have proven useful after examining different approaches to learning in adult education. Young (1996) states that, "Metaphors form visual constructs through which we associate, interpret and organize thought. They dominate and delimit our consideration of experience and phenomena. Because one's metaphor of teaching and learning interacts with fundamental issues such as the nature of knowledge and the nature of persons, it impinges directly on the way pedagogical decisions are made" (p. 79).
Postman and Weingartner (1969) suggested that many adult educators conceptualize teaching and learning through the use of metaphors. Winner and Engel (1980) used a matching task where the classification of one item in terms of recurring similarity to another item was scored as metaphorical. Furthermore, Vosniadou and Ortony (1983) asked their participants to complete similarity statements, including similes. The expressions tested "were often constructed idiosyncratic metaphorical expressions instead of actual natural language expressions."
Waggoner, Messe, and Palermo (1985) found out that the recollection and the construction of meaning for both literal and metaphorical expressions depends on the supporting contexts, such as extended and appropriately structured stories. Stones (1989) used short stories with familiar concrete nominal metaphors as targets and he found out that participants perform better when they are asked to paraphrase rather than explain the meaning of the metaphor. However, this has one drawback for children, as the meta-cognitive abilities that paraphrasing required usually develop late in childhood. Thus, such reasons could prevent participants from scoring well in the task.
For students who do not have a cultural orientation of the western background, metaphors from English Linguistics or English Literature textbooks might create confusion. According to Brown, "cultural knowledge" is too vast to teach in the context of English Literature, thus, ESL students should be taught "explicit strategies for making inferences from language" (1990, 11-17). Furthermore, Murray (1985, 7) states that without the inculcation of such strategies, students will interpret the texts according to their own background. Murray's recommendations are based on the "Schema Theory" (Adams Collins 1979), which is the body of research into reading comprehension. According to Adams and Collins (1979), a schema can be characterized as an "abstract knowledge structure" in the memory and it functions by interpreting, storing, and retrieving new information. This theory concludes that texts on their own do not provide meanings, but rather they direct to readers the construct meaning based on what they have acquired previously.