In a cultural and religious context, aetiology can refer to a particular kind of philosophy; one which looks to the past to explain the present, and views the future as a determined product of the past.
This concept exists in opposition to teleology, which is the idea that the past is a lead-up to the future, and that the present is a morass of possibilities.
For example, Judaism uses the Jewish Scriptures (or Old Testament as the Christians refer to them) as their Hitch-Hiker's Guide to Reality. The story of the Jewish people, and their relationship with their God is all a product of the Genesis tale, particularly the Original Sin, or Disobedience of Man.
In contrast, the Christian religion operates in a more teleological fashion, stating that the events of the past and present are just preludes to the big finalé, being the Second Coming and the end of the world.
Fairly simplistic illustrations, but it gets the general idea across. Aetiology is being concerned with the origins of history, and teleology is being concerned with the destination of history. There's no cause to regard the two as mutually exclusive, since your average thinker will be interested in explaining history in both directions.
Of course, each individual Christian or Jew (or member of any religion for that matter) will have their own take on these principles. YMMV. The examples I've used are just the quasi-official tenets of both religions.