Response: The Qur'an can be proven without a shadow of a doubt that it is the true word of Allah, as it can be tested and verified so. The proof is in the following:
"Will they not then meditate upon the Qur'an? Had it been from anyone other than Allah they would surely have found therein much discrepancy."
Here we have test that demonstrates that there is no error in the Qur'an, showing the truthful nature of the Qur'an. If a person disagrees, then the individual can take up the challenge to find a discrepancy in the Qur’an and when the person discovers that there is no discrepancy, then the only logical conclusion that can be derived is that whomever the author of the Qur’an is, the individual is a truth teller and righteous because all of the content in the Qur’an is without error, indecency, and immorality.
The Qur'an contains plenty of factual errors, but I'm not interested in listing them and sifting through your mental gymnastics. I'm more interested in questioning the assertion that Qur'an is free from immorality and indecency. Eternal torture of disbelievers whose "hearts" you veiled seems moral to you? Beating your wife is moral?
The question still remains as to who is the author? The Qur’an answers this question with the following test. The Qur’an states:
"And if you are in doubt as to what We have sent down to our servant, then produce a chapter like it, and call upon your helpers beside Allah if you are truthful."
Here we have a test which proves that it is not humanly possible to produce a chapter like the Qur'an and proves so by challenging all of those who doubt so to prove so by trying to produce a chapter like the Qur'an. For when trying to produce a chapter like the Qur'an, the skeptic will learn first-hand that such a thing is humanly impossible to do.
Pointless exercise, since it's inherently subjective. Conveniently, no rigid criteria was given to measure "likeliness" by, giving believers endless wiggle room. Many have undertaken this challenge and made chapters resembling those of Qur'an, but of course you would deny any resemblance because of your bias.
But before the a skeptic develops the common response of simply producing something in Arabic or claiming that the challenge is not valid because not being able to produce a play like Shakespeare does not mean that the play is from God so the same analogy applies to the Qur'an, let me further elaborate. The Qur'an, like any scripture, is inspiration. And like any scripture, its intent is to inspire people to follow its teaching. Thus the challenge is to produce something that is as inspirational as the Qur'an, for it is the inspiration of the Qur'an that is miraculous. And what is that miracle? The miracle is within the following:
It is impossible for a person/s to use speech or literature that goes against wants of the masses, which is invented by any person or people, to inspire enough followers amongst them to conquer a nation.
Such is YOUR understanding of the criteria. Tell me where the Qur'an explicitly mentions inspiration to conquer nations as the criteria by which to compare the chapters.
Not to mention the fact that there are other texts which meet your criteria. The Bible is the obvious one. US constitution. Plenty others, I'm sure. Attracting a bunch of devout followers is not as difficult as you might imagine, as evidenced by people like David Koresh, Jim Jones, Shoko Asahara, Joseph Smith, and many many more.
Topic: how should you respond to the particularly dumb proofs of the quran's miracle