Here's what the Orthodox theologian
Andrew Louth has to say from his excellent book
Discerning the Mystery:
- "... allegory is a way of holding us before the mystery which is the ultimate 'difficulty' of the Scriptures - a difficulty, a mystery, which challenges us to revise our understanding of what might be meant by meaning; a difficulty, a mystery, which calls on us for a response of metanoia, change of mental perspective, repentance" (p. 110).
- Allegory "is an attempt to respond to the mira profundatis of Scripture, seen as the indespensible witness to the mystery of Christ" (p. 112)
- Allegory is not a technique for solving problems, but an art for discerning mystery (p. 113).
- Allegory is "a way of focusing on the mystery to which the Scriptures bear witness" (p. 114)
Note that on this account, allegory is less a matter of the Christian interpreter playfully exercising his or her interpretative freedom with the text and more a matter of a disciplined penetrating of the text to that which is is really all about. Allegory thus presupposes the existence of an real textual referent.
Louth emphasises this dimension of penetration when he talks about the relation between the allegorical (or mystical) sense of the text and its plain sense (which he, rather misleadingly it seems to me, also calls its historical sense) as being one of movement, a movement through the plain sense to the spiritual sense. Thus he can say:
the movement to allegory is not at all a movement away from history, but we might say a movement into history, into the significance of the sacred events that are the object of our faith. The literal sense is the object of faith: this is what we are to believe, to believe in, in a God who meets us in history, becomes man in Jesus of Nazareth. The allegorical sense represents our attempt to understand the mystery we discern here. It is a move from fides to intelligentia (p. 116)
There is no doubt a move back again, from spiritual sense to literal, but I haven't got that far yet.