From The Logical Fallacies of the Documentary Hypothesis, Chapter 4:
The fifth reason why the documentarians do not believe the Pentateuch was written by a single author is that they make the unwarranted assumption that the author of the Pentateuch is not trying to convey a message. Most documentarians have never attempted to discern the overall message and purpose of the Pentateuch, an observation confirmed by the nonconservative scholar, David J.A. Clines: “Surprisingly, few scholars have studied the question of what thesis the Pentateuch in its final form is attempting to sustain.” Many documentarians do not believe that the final form of the Pentateuch is attempting to sustain any kind of message or thesis at all. For example, in his commentary On Genesis, Bruce Vawter proclaims,
The ideas proposed by Genesis are those of J and P, and, occasionally, of E…. It is this fact that justifies the procedure we follow in this commentary, taking Genesis piece by piece as it may be redivided into its sources. That is where the message of Genesis is.
Other documentarians believe that if the Pentateuch is conveying a message, it was created by mistake. Friedman says that when R combined P with JED, he created the view that God is both cosmic and personal and created the message that the cosmic God is concerned about each and every person. That view and that message have been essential parts of both Judaism and Christianity ever since. But that view and that message were created unintentionally. The authors of the documents never intended to convey that message and neither did R. It was the unintended by-product of the redaction process. Though Friedman and Vawter may disagree on whether the Pentateuch is conveying a message, they do share something in common: they both see anomalies within a work as evidence of multiple authorship rather than as clues pointing to the author’s message and purpose.
Every writer writes because he has a message he wishes to convey. This is not to say that every story, like an Aesop’s fable, has a moral to it. The author’s message may be the story itself (which, presumably, is the message of Carroll’s “Snark”). Or his message may be a piece of information or an idea or even a joke. Related to the message is the author’s purpose in conveying the message. His purpose may be to entertain us, to inform us, or to convince us. His purpose will lead him to choose his message and to shape it. If his purpose is to humor us, he will choose a story or joke that he feels is funny. If he decides that adding a few lines or rearranging some lines will make his message more effective, he will make those changes. The final product may not be funny at all—at least, we may not think so. But that’s not the point. The point is, he chose the story and he made the changes because he thought it would fulfill his purpose. In short, anomalies may appear in a work because the author thought those anomalies would help him to convey his message.
Look, for example, at what Alexander Pope does in his famous Essay on Criticism. During his sermonizing on how in poetry “the sound must seem an Echo to the sense,” he says,
When Ajax strives some rock’s vast weight to throw,
The line too labors, and the words move slow.
Most of his poem flows along in a steady iambic rhythm. This last line, however, breaks that rhythm. Is this evidence of multiple authorship? Is this evidence that a lesser poet added his own material to Pope’s original poem? Not at all. Pope is merely practicing what he preaches. In the words of one set of scholars, “The slight pauses before and after ‘too’ and the pause after ‘labors’ serve to slow the line down, and slowness is what Pope is talking about.”
Or look again at what he does only a few lines earlier when he deprecates predictable poetry:
Then, at the last and only couplet fraught
With some unmeaning thing they call a thought,
A needless Alexandrine ends the song
That, like a wounded snake, drags its slow length along.
The first three lines, as well as the lines in the rest of the poem, are written in iambic pentameter: they are each five feet long. But this last line is in iambic hexameter: it is six feet long. It even looks longer than the other lines of the poem. Again, is this evidence of multiple authorship? Again, no. An Alexandrine is a poetic line written in iambic hexameter. Pope deliberately uses an Alexandrine to satirize the needless Alexandrines of other poets. His satiric wit stands out because the line itself, with its extra foot, stands out.
Pope’s anomalies helped the author to fulfill his purpose and convey his message. The anomalies in the Pentateuch were intended to do the same. This is not to say that every anomaly identified by the documentarians is a real anomaly. Before we can hear the message of the Pentateuch, we need to determine which anomalies are real and which are mere illusions.
 David J.A. Clines, “Introduction to the Biblical Story: Genesis-Esther,” in James L. Mays, ed., Harper’s Bible Commentary (San Francisco: Harper and Row, Publishers, 1988), 83.
 Bruce Vawter, On Genesis (Garden City, NY: Doubleday and Company, Inc., 1977), 23.
 Wrote, 216.
 This is precisely the view taken by Michael Holquist in his “What is a Boojum? Nonsense and Modernism,” Yale French Studies, XLIII (1969), 145-164, reprinted in Gray, 402-418.
 Sylvan Barnet, Morton Berman, and William Burto, An Introduction to Literature, 2nd edition (Boston: Little, Brown and Company, Inc., 1963), 363.