| Metaphor has been studied for more than two thousand years, from being regarded as a pure rhetoric device to being redefined as a cognitive phenomenon. The publication of Metaphors We Live By of Lakoff and Johnson in the 1980s ushered in the Conceptual Metaphor Theory. Since then, the theory has been widely applied to the exploration of ideologies in political discourses, for it claims that metaphor, as a way of understanding the world, can effectively reveal ideas and thoughts of human beings. However, Charteris-Black argued that the cognitive approach only concerns how metaphors are interpreted based on individual experience and neglect the influence of social context on certain metaphor choices. He proposed a new model of Critical Metaphor Analysis that mainly combines the theoretical results of Conceptual Metaphor Theory and Critical Discourse Analysis. The innovation of this approach is to research metaphor from a broader view—explaining how particular metaphor choices are made to achieve persuasion by considering not only individual factors but also social resources.The present study takes American Presidential Inaugural Addresses (APIAs) from 1949 to 2013 as the research object. It is designed to explore metaphor application in APIAs from both a synchronic and diachronic perspectives under the framework of Critical Metaphor Analysis. The study is conducted in three stages:metaphors are first identified and grouped into different categories according to their source domains; next, the underlying conceptual metaphors are generalized and detailed analysis is given to interpret the mapping mechanism; finally, the reasons for metaphor changes are accounted for within the social and historical context by observing the diachronic distributions of metaphor.The results show that the identified metaphors in APIAs can be grouped into eight categories. They are respectively from the source domains of war, journey, human, building, family, light/fire, weather and stage. From those metaphor categories, eleven conceptual metaphors are generalized. They are all structured as domain mappings from people’s familiar experience onto complex political issues, which can help enhance the intelligibility of inaugural speeches and achieve the effect of persuasion. Through those mapping structures, it is found that America tended to seek hegemonism after the end of World War Ⅱ and at the same time pursued global cooperation to deal with world-wide problems. It is also revealed that the frequency of metaphor employment in APIAs is closely associated with the social context. The distributive trends of metaphor usage to some extent reflect the stability and variety of American political development during this period.This study contributes to making people more aware of America’s political ideology since the end of World War Ⅱ. It further proves the importance of metaphor in politics. Besides, the analysis from a diachronic perspective fills the gap in APIA studies and provides an important method for comprehensively encoding metaphor in political discourses. |