Below is a recent blogpost that I put up. The argument I make in it is either very clever or pathetically dumb. Would really appreciate it if people could weigh in (Especially if there are any logicians here)
http://captaindisguise.blogspot.com/2013/02/qurans-error-sura-482-if-quran-had-been.htmlI will copy/paste the main part of it below;
Qur'an's Error: Sura 4:82 "If [Quran] had been from other than Allah, they would have found within it much contradiction"
Sura 4:82 would be found in the average Islamophile's list of favorite verses. It is often quoted in the form of a challenge to Rationalists and others. Sura 4:82 states the following; (
http://quran.com/4/82)
Sahih International
If it had been from [any] other than Allah , they would have found within it much contradiction.
Muhsin Khan
Had it been from other than Allah, they would surely have found therein much contradictions.
Pickthall
If it had been from other than Allah they would have found therein much incongruity.
Yusuf Ali
Had it been from other Than Allah, they would surely have found therein Much discrepancy.
Shakir
And if it were from any other than Allah, they would have found in it many a discrepancy.
Dr. Ghali
And if it had been from (any where) other than the Providence of Allah, indeed they would have found in it many differencesUtilizing this verse, the Muslim apologist will demand reasonable individuals to show an error in the Qur'an. They will also state with exuding confidence that no one in 14 centuries have been able to show an error in the Quran.
Such a conversation usually unfolds in 2 ways; i) the Rationalist ignores the apologist or ii) the Rationalist shows some of the errors in the Quran (creation from blood clots, setting of sun in a muddy spring, seminal fluid from the back, flat earth, denial of human evolution etc).
Whenever ii) occurs, the apologist will usually dismiss any evidence and can be seen asserting his literary liberty to interpret the sentences however he wishes to. Given the spectacular vagueness of much of the Qur'anic statements, the conversation almost always reaches an impasse with each side rejecting the other's interpretation (and perhaps moving on to a round of creative insults).
However it seems to be the case that neither the apologist nor the Rationalist has reflected carefully on the challenge itself. The great irony of the Qur'an is that the very verse that issues this challenge also meets the challenge i.e. Sura 4:82 is an error on it own since it constructs a false conditional statement.
The verse states that if the Qur'an was from a source other than Allah, then it would contain many errors or contradictions.
Now consider this question, is it possible for a man-made work to contain no errors or contradictions? This should be uncontroversial. There are countless human texts that would be free of any errors.
Then, if it is the case that it is possible for man-made works to be free of any errors, then it is also possible for the Qur'an to contain no errors and be man-made i.e. be from a source other than Allah.
Given the above possibility, Sura 4:82 constructs a false conditional for it is easily possible for the Qur'an to be "from other than Allah" and yet contain no errors.
Thus, Sura 4:82 is an erroneous statement.The concept is fairly simple. For a detailed explanation, continue along. The following proof will use terms used in the discipline of Logic.
In Logic, certain statements are called "conditional statements" when it consists of a relationship between 2 (or more) atomic statements where one is the antecedent and the other is the consequent. These are usually denoted as "If ... then" statements. For example;
"If John is a human, then John is a mammal"
The antecedent in this case is "John is a human" and the consequent is "John is a mammal". In logic, this statement is equivalent to it's "contrapositive statement" which in the above case would say;
"If John is not a mammal, then John is not a human"
In Formal Logic, any conditional statement can be symbolized in the following manner;
"P --> Q"
=(this is equivalent to its contrapositive)=
"~Q --> ~P"
P symbolizes the antecedent; Q symbolizes the consequent; '~' symbolizes negation (i.e ~P means "not P" or "P is false"); '-->' symbolizes the conditional relationship (i.e. "~Q --> ~P" means "IF not Q THEN not P)
A fair knowledge of these simple concepts alone are sufficient to examine the Qur'anic statement in Sura 4:82. Consider the verse,
"If [Qur'an] had been from other than Allah, they would have found within it much contradiction"
The verse expresses a conditional relationship between two atomic statements. The antecedent is the atomic statement "The Qur'an is not from Allah". The consequent is the atomic statement "Errors will be found in the Quran" (Verse rephrased for simplicity). Thus the verse is stating the following relationship;
"If the Qur'an is not from Allah, then errors will be found in the Quran"
Let A = "The Qur'an is from Allah". Thus ~A = "The Qur'an is not from Allah" (which is the antecedent above).
Let E = "Errors will be found in the Quran" (which is the consequent).
The above statement can be symbolized as
"~A --> E"
As stated above, this statement is logically equivalent to it's contrapositive statement which would state the following;
"~E --> ~(~A)"
==
"~E --> A"
==
"If no errors are found in the Qur'an, then the Qur'an is from Allah"
For those who were unable to spot the mistake in the original verse, its contrapositive statement should certainly render the issue clearer. A conditional statement is false if it is possible for the antecedent to be true and the consequent still false. Such is the case for this verse.
Take the original verse for example, it is possible for the antecedent to be true and yet for the consequent to be false i.e. for the Qur'an to be not from Allah, and at the same time be free of errors. Likewise, for the contrapositive statement, it is possible for there to be no errors in the Qur'an and yet at the same time, not be a product of divine intelligence.
It would clearly be absurd to state that any piece of text that does not contain errors is from Allah and yet this is what the Qur'an claims. Certainly, for the Muslim apologist (especially ones acquainted with the principles of Propositional Logic), this is an irrefutable error in their Holy Book. Their only option to rescue the Qur'an is to show that it is impossible for the Qur'an to not be from Allah if it had no errors in it. Of course, this is not at all a tenable position as Humans have produced countless texts with no errors in it.
Thus, offering one of the greatest unintentional ironies, the very verse that challenges one to show errors in the Qur'an is on its own an irrefutable error. 
Topic: Qur'an's Error: Sura 4:82 "If [Quran] had been from other than Allah ..."