I love reading Peter Leithart's blog. He had a brief but brilliant summation of typology recently:
Typology is a philosophy of history.Read the full post over at Leithart's blog.
It is also a theory of meaning.
Typology is a historical theory of meaning, a theory of historical meaning.
That Matthew can say “Out of Egypt I called My Son” is fulfilled in Jesus isn’t evidence that Matthew was a midrashist. It’s not merely a hint about how to read the Old Testament. It’s a pointer to the character of history and the nature of meaning. Texts mean the way Matthew says Hosea’s text means; history’s contours are the contours that Matthew discerns in Hosea’s reference to the exodus.
Typology is the beginning of wisdom.