Cognitive Process of Metaphor Interpretation in Communication

   Metaphor plays an important role, not only in literature but in the discourse of law or natural science which people regard as divorced area from such a poetic language. It also takes a large place in mass communication such as advertising, and it is sometimes used as a key term of political propaganda (for example, "information super highway" coined by the vice-president of America). These facts prove that metaphor has a close relation with communication, but metaphor has been studied without considering communication in which it is used.
   In this essay, I argue that as long as ignoring the communication in which metaphor is used, we never explicate what metaphor means and how metaphor is interpreted. In terms of pragmatics, the meaning of metaphor is not 'sentence-meaning' that is independent of the context of communication, but 'utterance-meaning' that depends on it. So the appropriate theory for investigating metaphor must be provided by pragmatics which studies language use (i.e. communication), not by any study which investigates language separately from its use.
    There are three main problems on metaphor, which will be solved in this essay. Consider such a conversation as below.

A1)	What fellow is your neighbor John?
B1)	John is a wolf.
A2)	I remember your grandpa keeps a strange pet. The name is ... John, I remember. But I forgot what animal he keeps...
B2)	John is a wolf.

Problem-1 :

B1 has no difference with B2 in expression, but B1 is perceived as an example of metaphor and B2 as a literal. What tells us that B1 is a metaphor and B2 is not?

Problem-2 :

Does the expression "John is a wolf" have two kinds of meanings (i.e. metaphorical meaning and literal meaning) ?

Problem-3 :

Does B1 have difference with the literal expression "John is dangerous" in meaning? Can we replace a metaphor with some literal expression without changing its meaning?