By scripturalism I mean "Scripture-is-the-Word-of-God-ism."  To make it relevant to a scripturalist, it must be defined as "My-particular-scripture-is-the-Word-of-God-ism."  Scripturalists interpret scripture by whatever interpretation best allows the possibility of its being true.  Non-scripturalists interpret scripture by whatever interpretation best accounts for its existence.

I'm defining scripture as a finite set of documents believed by a particular group of people to contain official messages from a God to whom all mankind is accountable.

Even if monotheists are given credit for most reasonable explanation for the existence of scripture, they immediately blow it by the introduction of scripture as "the Word of God".  Once they do that, the atheists can rationally walk all over them.  I cannot blame any atheist for being an atheist when the only alternatives he is presented with are either the irrationality of pantheism, or the absurd God of scriptural monotheism in any of its forms.  If atheists are created by a God, and that God has his head on straight, I see no way for him to blame them either.

Scripturalism comes in at least 3 forms that we are all familiar with:  Jewish, Christian, Muslim.  We could add Mormon scripturalism, or call it a subset of Christian scripturalism, depending on how Christian is defined.  Each of these forms can be divided into subsets ad nauseam.  The number of subsets is irrelevant.  What matters is, why is there more than one supposed Word of God?  Why do they all exist in a world full of people who are supposedly accountable to one God?  Right off, we have at least three different scenarios.

Jewish scripturalists will say:  Torah is the word of God.  Jesus was either a fraud or crazy or at least mistaken.  Koran and Book of Mormon are written by frauds.

Christian scripturalists will say:  Torah is the word of God, but incomplete.  New Testament completes it.  Koran and Book of Mormon are written by frauds.

Muslim scripturalists will say:  Torah and New Testament are corrupted by copyists.  Koran is the Word of God.  Book of Mormon - written by a fraud.

Mormon scripturalists, yada yada.  You get the picture.  Pantheists and panentheists also have their proposals where everybody really agrees with everybody else, and disagreement is just an illusion.  But those proposals are internally contradictory, therefore illogical, therefore worthless to a rational person.

If any one scripturalist position is right, all others are necessarily wrong.  That means sincere people trying to obey God are erroneously believing the wrong one, and being punished for it, according to the right one, regardless of which one is right.  If any such position is correct, then why would its omnipotent and omniscient God even allow bogus scriptures to exist?  Scripturalism paints a picture of a God who is either stupid, or evil, or just plain impossible.

For the rest of this essay I'm focusing on Judaeo-Christian scripture for convenience, and because I know it best.  Judaeo-Christian scripture gives us a God who is omnipotent, but can't lie.  Omniscient, but he learns and forgets things.  Unchanging, but he changes the rules.  Good, but he burns people in hell forever.  His alleged Word is confusing, yet he's "not the author of confusion".  Absurdities within absurdities.  Religio ad absurdum.

Of course, there are smart scripturalists who can figure out ways around all these things.  But they disagree on how to go about it.  Even if one of them were absolutely right, it would only mean God is so obnoxious as to confuse everyone except him.

Several scenarios explain the existence of scripture better than scripturalism:
1.  Atheism explains it better.  So does deism.  By either worldview, scripture developed quite independently of a God, for purely natural reasons.
2.  Psychological reasons:  Parents make you feel safe.  When they die, you want to imagine they still exist somewhere.  Therefore afterlife.  Therefore deification of ancestors.  Therefore tribal gods.  Therefore one god in charge.  Scripture provides "evidence" for his existence allegeable evidence.
3.  Political reasons:  Kings want to legitimize their position by divine sanction.  Therefore they have good reason to push a god.  Scripture provides a marketing tool.
Cynical as these scenarios are, they make better sense than any scripturalist scenario to anyone who is not already a scripturalist.

But we don't need to get cynical.  Given the premise that this world is preparation for the next, then maybe we have mutually exclusive scripture packages here because we will encounter even more of them on the next level.  Since we have free will here, there's probably free will on the next level.  Since on this level we are challenged to overcome the temptation to do immoral stuff, that temptation probably exists on the next level.  Otherwise why would we have to learn morality at all?  If the existence of God is unproven on this level, maybe it is also unproven on the next.  Maybe it remains eternally unproven.

Nobody can learn to face the brute facts of existence all at once.  When we move too fast, we create dogmas.  Minds need time to adjust.  Scripture permits that.  It gives frightened people assurance of safety.  It allows dumb people to believe dumb stuff.  And sometimes warm fuzzy lies are all that keeps them out of despair.  Children likewise, while they learn to interpret it more sensibly.  It allows adults to explore various spiritual locations by their various interpretations of scripture.  So maybe a monotheistic God exists, and allowed scripture to develop naturally for those reasons.  And maybe no God exists, and scripture was fabricated for those reasons.

Another possible reason for the existence of scripture is a monotheistic God who wants to test the behavior of free will creatures in various world systems.  Maybe in some systems he controls scripture tightly, and in other systems loosely, or not at all.  Our planet may be one of many survivability tests.  If God needs to test things, he would not be omnipotent or omniscient.  But unless he intervenes, scripture would naturally evolve to say he is anyway, because flattering God feels humble and therefore safe.  And safety is the biggy for religionists.  Scripture would naturally evolve to say God is omnipotent and omniscient, unless God took action to prevent it, which he may in some world systems.  There may be worlds in which God totally controls scripture, and it actually is his Word.  But to say that this is such a world is totally ridiculous worthy of ridicule.

The Genesis account alone is full of so many absurdities that anyone trying to defend it as truth is forced to commit countless violations of common sense and normal probability judgment.  You atheists please note that I did not include violations of logic and science, because a competent scriptural inerrantist can manipulate the principles of word interpretation so skillfully as to resolve any Biblical contradiction or error.  If you don't believe that, test them.  Inerrantist have a wide arsenal of tactics to resolve contradictions and make errors unprovable.  Here are a few examples:

Any rational statement has a literal implication only one unless it's literally ambiguous. It also has at least one intuitive implication.  If the literal implication matches the intuitive implication, the statement is unambiguous.  If they don't match, there is room for misunderstanding.  For example, if I say, "I could care less," the literal implication is "It is possible that I could care less."  The intuitive implication is "I could not care less." - the exact opposite of its literal implication.  If the literal implication of a scriptural statement shows a contradiction or error, then the inerrantist will assert that the author intended an intuitive implication, of which there may be several from which to choose.  And he will assert that the intent of the author overrides literal content.

But not always.  There are exceptions.  For example, eternal damnation is definitely implied in several places in the New Testament.  But that's an intuitive implication.  Anyone with a rudimentary sense of justice knows that eternal damnation is grossly unjust, if not absurd.  So the inerrantists will point out that the Greek words translated eternal and forever don't necessarily mean that.  Technically they mean age-lasting lasting into the ages.  That may be a long time, but not necessarily forever.  So literal implication trumps intuitive implication when it sells the product better.  And of course they never mention that the same reasoning negates eternal life also.

Another inerrantist tactic:  "You have to look at the passage in context."  Now that's a sensible principle of interpretation.  What could be wrong with that?  Nothing, if it's used with common sense.  But inerrantists take it well beyond common sense.  The real principle they're employing, but not stating is this:  "You have to look at enough of the context to allow enough ambiguity of the passage in question to permit the possibility of the desired interpretation."

Another inerrantist tactic:  Cite supportive passages and ignore erroneous passages.  Ezekiel prophesied that Tyre would be scraped clean.  250 years later Alexander fulfilled that prophesy.  Very impressive until you read it more carefully, and see that Ezekiel said specifically that Nebuchadrezzar would accomplish the scraping.
Also, Ezekiel and Jeremiah both prophesied that Nebuchadrezzar would conquer Egypt. That never happened.

What about all the prophesies Jesus fulfilled?  Actually that's not surprising when any time Jesus did something vaguely similar to a Torah verse, his act becomes a fulfillment, and the verse itself becomes a prophesy.

Inerrantists have many such tactics.  If all else fails, they can always fall back on different senses of terms.  Consider these two statements:

A equals B.     A doesn't equal B.

Each statement contradicts the other.  Well, technically they only contradict when you're talking about the same A and the same B.  Otherwise you can always assert that each statement means A in a different sense, or B in a different sense, or even equals in a different sense.  So contradiction exists only as an abstract with no practical examples of it.  These are the extremes to which inerrantists will go, to defend their faith not in God, but in scripture.

To make it worse, inerrantists don't even admit that they are inerrantists until they have defined the term down to where it has no practical application.  They define inerrancy as the belief that the original documents of scripture contained no contradictions or errors.  But since we have no original documents, the position cannot be disproven.  They then proceed to ignore this definition, and defend existing scripture as though it descended from inerrant documents, the content of which they are free to speculate on.  The inerrancy they define is not the inerrancy they defend.  When you attack what they defend, they hide behind their definition, which is unassailable but irrelevant to the points being defended.

The "inerrant autographs" defense is the reverse of a strawman argument.  A strawman argument is an easily refuted argument that's irrelevant to the point being defended.  The "inerrant autographs" defense is an unassailable (though unprovable) defense that's irrelevant to the point being defended - which is that the Bible contains no errors.  It serves 3 purposes:
1.  to give young or stupid Christians the illusion that the Bible contains no errors
2.  to give smart Christians, who know the Bible contains errors, an unassailable defense
3.  to give those smart Christians a badge of legitimacy in the eyes of the young or stupid Christians

I can agree that if God wanted to communicate things to humans, scripture might be one of the ways he chose to do it.  It works quite well to convince a lot of people that it's good to be God-compliant.  Unfortunately scripture also convinces a lot of people that they should be scripture-compliant.  And it is this that causes so many world problems.  Not theism or monotheism, but scripturalism.

If scripture is not the Word of God, does that mean there is no God to whom we are accountable?  Of course not!  It just means he didn't choose to communicate in a way that could be so easily misinterpreted, and so full of absurdities apparent absurdities if you must.

If scripture is not the Word of God, does it mean he has no objective standard by which to judge us?  Not at all.  We can all be rightly judged by the degree to which we do what we believe God wants us to do.  If God is just, he will judge everybody justly, whether they believe in him or not.  He can judge atheists by the degree to which they did what they believed they should do, in accordance with whatever sense of morality he gave them.