In David, King of Israel, and Caleb in Biblical Memory, Jacob L. Wright sees the biblical text as like a layer cake. It is not the product of someone stitching together fully developed narrative sources like the documentary theory claimed for the Pentateuch. Instead, he has a supplementary theory. Those who created the text as we have it, developed early traditions by layering on supplemental material, some of which they just invented.
There are ways to see what some of the earlier layers looked like. In regard to Caleb his method is to focus on the minor and incidental things that do not fit the motives of the redactor. The story of Caleb now centers on the idea from Numbers 13-14 that Caleb was one of the 12 spies Moses sent to scout out the Judean territory.
In terms of the narrative, this story functions to show why the Israelites ended up entering the land from the east. In one of the very few historical judgments Wright makes, he concludes that the ancestors of the northern Israelites came from the east. So when editors from Judah retold the story, they had to give a reason that the Exodus people did not come directly north from Egypt and enter the land from the south.
There were layers of tradition to explain this. Probably the oldest was the claim that God told them to go around because they would face war on the northern route and be tempted return to Egypt (Exodus 13:17). Later editors supplemented this with a story that spies came back with a negative report about the southern approach. Moses changed course, and all the spies died before reaching the promised land.
Finally, other editors added Caleb to the story. He was the one spy with the courage to attempt a conquest from the south. But the rest of Israel did not share his courage so they all died in the wilderness. But God commended Caleb as worthy and allowed him to take part in the conquest of the land while his whole generation suffered the divine punishment of dying off in the wilderness.
Joshua 14-15 intends to complete this story. But it also builds on some older layers. A passage that does not really fit the tradition of Caleb as a mighty warrior is the one reported in both Judges and Joshua that Caleb did not capture Debir himself, but offered his daughter, Achsah, to a warrior who could take the place (Joshua 15:15 ff. Wright thinks the parallel passages in Judges 1 are a later layer).
The warrior who took Debir was Othniel, a son or descendant of Kenaz. But, in a sequel to the story, Othniel is secondary to Achsah; who, by being pretty assertive, obtains the transfer of some water rights from the Calebites to the Kenazites. This account is probably the oldest story about Caleb. It is now isolated from its original context.
There is also embedded in Joshua 15 a layer that has Caleb drive the Anakites out of Hebron (Joshua 15:14). But overlaying this is the story of how Joshua struck Hebron with the “edge of the sword” and took it (Joshua 10:36). So now the story emphasizes that Joshua alloted the land to Caleb.
The story as it now stands has Caleb spying out the land at age 40, and then finally obtaining Hebron in his 80s. This may be one reason that the military feats of Caleb are downplayed in the Joshua story. Still, the story is an example of war commemoration. Caleb comes off as one of the few members of his generation willing to fight for the land.
The main thrust of Wright’s argument is that Caleb as the person who obtained, along with his son in law and daughter, portions of southern Judah, has been transformed by the spy story in Numbers 13-14 into an exemplar of religious and patriotic virtue for theological and nationalistic purposes.
In Numbers, Moses sends out 12 spies and Caleb is the one representing the tribe of Judah. Wright sees significance in the fact that Nahshon, an ancestor of David, does not get chosen for this. Many interpret the spy account as a pro-Judah story. Wright agrees that there is some truth to that, but also points out that it is Caleb alone, and not the tribe of Judah, that displays great courage. So the story is more likely meant to explain the position of the clan of Caleb in later Judah.
You cannot use an empirical method to study Caleb. With David, there are some inscriptions, possibly some buildings, and correlations with Philistia and Phoenicia. There is none of that with Caleb. All we have is the text. And the text obviously has other interests than reporting about historical events. Thus, Wright does not treat even the earliest layers as reflecting historical truth.
Still, he does make a few historical claims. One of them is that Hebron, rather than Jerusalem, was the capital of Judah during the early part of Judah’s history. He bases this on skepticism about the existence of a united monarchy and the geographical centrality of Hebron in Judah.
But, precisely because Hebron was an important center, I would not rule out there being preserved there a true memory of Caleb as its founder. Also the site of Tel Masos in the Beer-sheba valley seems to show a large early Iron Age settlement with pottery and houses like the ones in the central highland villages. So the possibility that there was Israelite or Yahwist encroachment from the south as well as the east has some empirical backing.