The Old Testament has a picture of its central character, God, that is on its surface inconsistent, with apparently contradictory features. But a deeper reading shows a deep consistency: a consistent but from our point of view complex character displayed in a variety of circumstances, from a variety of points of view, and also reflected in the emotions of narrators and interactions of other characters.
I shall not try to defend this reading of the Old Testament here. It cannot be done in a post, and maybe not even in a book, and certainly not by me. One must drink in the texts. Personally, I have found very helpful our Department Bible study in this regard. We are doing Book III of the Psalms (Pss. 73-89), and this has been one of the things that has led to this post.
Now, there come to mind four prima facie plausible explanations for the portrayal of a single character across a large body of literature by a large set of authors.
- Imitation by a number of authors of a canon of primary texts or stories originally by a single author.
- Harmonization by selection of texts and/or editorial work on particular texts.
- Cooperative authorship.
- A modeling of the character on an actual person with whom the diverse set of authors all interacted "in real life."
If (4) is the right explanation, then the fact that the authors wrote over a period of many centuries, in different social circumstances, together with the essential otherness of central character of the texts, makes it most unlikely that any mere human was the model. And the simplest explanation is that the authors were in fact interacting with the person they claim to be describing—Y*WH, the God of Israel. Therefore, if (4) is true, then we have strong evidence that God exists. Observe that it is not uncommon for the same person to have apparent surface differences as seen in different contexts and by different people—we call this "complexity" in the person and it lends reality to the person (which character complexity in the case of God is, I think, compatible with ontological simplicity, but that's a different question).
Note that the deep consilience not only suggests that the various authors interacted with the same person, but that they did not do so in a shallow way. It is possible to have portrayals of the same person by different people who were acquainted with the subject where there isn't such a consilience—I feel this way in the case of Plato and Xenophon's respective portrayals of Socrates, though I could be wrong (I have not drunk in the Xenophon texts sufficiently).
If (1) were the right explanation, we would expect shallow consistency in the portrayal of the character, and quite likely some deep inconsistencies, whereas we observe the opposite. It is hard for one author to take another author's character and portray that character in a consistent way, and the likely result of an attempt to portray that character is that one will have a similarity of outward mannerisms, but to a careful reader (or viewer) it just won't be the same character but an impostor. For instance, the Sherlock Holmes of the "New Adventures of Sherlock Holmes" TV series from the '50s is a case in point (this is the most absurd example from the seires). But when two authors portray different surface detail with a deep consistency, then we have something quite unexpected on a copying hypothesis. Granted, this could result from literary genius combined with depth of appreciation of another's work on the part of the copyist, but such a combination is rare. Most literary geniuses create characters on their own, often even when the character bears the name of some historical figure. And the Hebrew Scriptures weren't just written by two or three authors, but by a much greater number. Thus, explanation (1) does not fit the phenomena very well.
As for (2), again harmonization might explain doctrinal agreement and agreement as to surface features, but unless the harmonization takes the form of a rewriting of the whole body of texts by a literary genius, it would not produce a deep consilience in the central character. And no such unified rewriting in fact happened: the Hebrew Scriptures retain a great diversity of genres and styles. Another striking feature is that at least as regarding texts from before around the 4th century BC, it does not appear that there was much in the way of centralized selection. It seems that the main criterion for canonicity in the first century—to the extent that the concept of canonicity existed—was not deep consilience in the character of God, but something more extrinsic like Hebrew-language authorship combined with venerable age.
Option (3) could work with a small number of contemporaneous authors—but certainly not with the great number of authors of the Hebrew Scriptures strung out across centuries.
So that leaves option (4), and so we have good reason to think that at least a number of the authors of the Hebrew Scriptures had encountered the character of God in reality.
What does the New Testament add to the argument? I think the deep consilience with apparent surface difference continues. So the argument is strengthened. And another point emerges. Jesus Christ, although typically not explicitly portrayed as God, is portrayed in a way that gives him a deep consilience of character with the Y*WH of the Old Testament. Just to give one example, he appropriates, in a credible way, God's desire to gather the Israelites to himself like a mother hen.
May we be thus gathered to him.
Of course, I do not claim originality for this argument. It is inspired by similar arguments seen in various places. Nor do I promote this argument as a way of convincing atheists. Because the evidence of the deep consilience needs to be gathered over years of drinking in the Scriptures, and maybe this can only be done while living the life of the community that has produced the Scriptures (i.e., the life of the Church or of the Synagogue), this argument, while of significant epistemic weight, may only be evidentially useful to Christians. Yet, God can help someone not living the life of the community to see the consilience, so it could have some value outside the community, too.