Initial indications can be gained by considering why Israelites were permitted to use lots but not extispicy, when both are provoked forms of deductive divination. The two are simply variant mechanisms for placing an oracular request before deity. The major difference between them is found in the basis of how the sign is read. Mystic speculation is not necessary for deriving meaning from lot casting—the answer is transparent. In contrast, the reading of exta is entirely premised on such mystic speculation.
