What kind of diversity?
Well, let’s recall the very nature of the method. The method seeks to uncover original sources behind the final product. The critic posits that contradictory accounts are evidence of diverse sources created or developed by distinct authors. (We can save the greater complexity of communal development vs. individual authors for another occasion.) Why posit this? Again, because it makes little sense to contend that one and the same man could affirm contradictory things.
Ah! We have found a major player in the diversity studied. The critic considers one major kind of diversity to be contradiction.
What is contradiction? Contradiction is the relation between two statements both of which cannot be true. One must be true and the other false. For example: It is raining. It is not raining. These cannot both be true. Indeed, one must be true and the other false.
How, according to some of these critics is contradiction present? By implication or indirectly. Example. Gen 7:2 “Of all the clean animals you must take seven of each kind, both male and female.” Again, Gen 7:8 “Of the clean animals and the animals that are not clean … two of each kind boarded the ark.” And Noah “did all that Yahweh ordered” (Gen 7:5). So what is it, one pair of each clean animal or 7 pairs of each clean animal? Seven pairs and one pair are not in immediate contradiction. But, since “7 pairs” includes the implication “not just one pair” and the affirmation “one pair” seems to imply “just one pair,” say some critics, one account contradicts the other. The same man cannot affirm both statements. Ergo, there are in the final text at least two original sources.
Other diverse characteristics are also observed, lining up with the text of 7 pairs and that with 1 pair. The net result looks like this: one set of texts has characteristics A, B, C, D. The other has characteristics G, H, I, J. And this duality of sets of characteristics shows up in other texts, such as those of the creation accounts. The inference is reinforced: There seem to be (at least) two primary sources behind the final text.
Analogy. Say our civilization comes utterly to be destroyed, because it has abandoned its one true God and his one true Savior who gave us the one true religion which we also have spurned. Say we are diversified and confused, in the midst of our building our own Babel. Say our efforts to unite as one, under one government, quite top heavy, without any appreciation of the family, friendship, local authority, place and pilgrimage. Say technology falls into oblivion, etc. In hundreds of years, we work our way back to technology. We happen to re-invent digital CDs. Then, someone unearths an old copy of the Beatles song, “A Day in the Life.” Someone listens with a “historical critical” ear to the song. He discerns that there are parts of the song with a certain kind of melody and beat and voice, and other parts of the the song with a diverse kind of melody and beat and voice. He infers that this apparently one-authored song is actually dual-authored. He would have no actually separate instance of these two sources. He simply infers it with his insight into this diversity. As a matter of fact, he would be correct. There are two authors: Lennon and McCartney.
This is in a nutshell what the source critic is doing with his enterprise. Examination to follow.