From something I'm working on this week:
By literal, I refer to words taken in what we might call their most basic or everyday sense. This definition is not without complications, but it will suffice for our purposes. There are of course dead metaphors too, whose ordinary sense was originally metaphorical (e.g., a “wild goose chase”), but in such instances a little reflection usually suffices to show that we are looking at an expression that was originally metaphorical.  To consider Christ’s death a sacrifice, for example, is a dead metaphor, for normally someone living in the Mediterranean world would not have called a crucifixion a sacrifice in the manner of a temple altar. In time, such metaphors can become the everyday sense of a word or expression, even if its originally metaphorical nature is evident.
A metaphor then is the creation of a new semantic pertinence by the comparison of two unlike things.  We should distinguish between the use of words "literally" and the use of metaphors as the intended meaning of an author. The “plain sense” or what we might call the intended sense of a sentence may involve metaphors that were intended by the author. "He worked like a dog on this project."  There is a non-literal use of language in this sentence, but it is intended.
By “figural” interpretation, then, I refer to metaphorical interpretation on the part of a reader that was unintended by the author of the text being read. This figural interpretation can take place on any level from the non-literal interpretation of a single word to a full blown allegory. In an allegory, multiple features of the plain meaning are systematically taken to represent some other set of truths. The Parable of the Weeds is an allegory, where each soil in the surface story represents a type of person responding to the word of God...
 Lakoff and Johnson would argue that all language was originally metaphorical and thus that all "literal" language ultimately consists of layer after layer of dead metaphor. See George Lakoff and Mark Johnson, Metaphors We Live By (Chicago: University of Chicago, 1980).
 P. Ricoeur, Time and Narrative, vol. 1, trans. by K. McLaughlin and D. Pellauer (Chicago: University of Chicago, 1984) ix. See also chapter 3 of Interpretation Theory: Discourse and the Surplus of Meaning (Fort Worth, TX: Christian University, 1976) 45-70; and chapter 3 of The Rule of Metaphor (London: Routledge & Kegan Paul, 1978 [Fr. 1975]) 65-100.
 In my more general use of the word metaphor here, I am including similes and other non-literal speech as subcategories of metaphor as a general category.