Quran is so incoherent that forget about a normal person, even thousands of the top commentators of Quran of the last 14 centuries are trying to understand it, but still unable to understand it. 

For example, the verses which were revealed during the Meccan period, they are present in the Medinan period Surahs and vice versa, making it impossible for a normal person to understand which thing is talking about which incident. 

This disorder is not limited to the Surahs (Chapter), but this disease goes beyond this when even in a single verse (i.e. sentence), the first part is talking about one event, but the second part is talking about another event which took place years apart, and then the 3rd part starts talking about the 1st event again. 

For example, look at this verse of Quran:

(Quran 5:3)

(1st part of the verse) Forbidden to you is that which dies of itself, and blood, and flesh of swine, and that on which any other name than that of Allah has been invoked, and the strangled (animal) and that beaten to death, and that killed by a fall and that killed by being smitten with the horn, and that which wild beasts have eaten, except what you slaughter, and what is sacrificed on stones set up (for idols) and that you divide by the arrows; that is a transgression (2nd part of the verse) This day have those who disbelieve despaired of your religion, so fear them not, and fear Me. This day have I perfected for you your religion and completed My favor on you and chosen for you Islam as a religion; (3rd part of the verse) but whoever is compelled by hunger, not inclining willfully to sin, then surely Allah is Forgiving, Merciful.

All the commentators of Quran are unanimous thatَ

  • The first part of this verse is about Haram (prohibited) foods, and this order was revealed in the 6th Hijri year at time of Pact of Hudaybiyyah.
  • But the 2nd (middle) part of this verse suddenly started talking about "Perfection of Religion", and this part was revealed at totally different time in the 10th Hijri year, about 81 days before the death of Muhammad. And this part has nothing to do with the previous part of the verse.
  • And the 3rd and last part of the verse (i.e. sentence) again returns to the first incident about Haram foods, which revealed at incident of Pact of Hudaybiyyah in the 6th Hijri year

Maulana Modoodi wrote in his commentary of Quran under this verse:

"According to the authentic traditions this 2nd part of verse (about the perfection of religion) was revealed at the time of "Last Sermon" in the 10th Hijri year. But the initial part of the verse was about Pact of Hudaybiyyah (which happened in the 6th Hijri year). 

Maulana Taqi Uthmani wrote in his commentary of Quran under this verse:

Some Jews said to Umar Ibn Khattab, had this verse "This day have I perfected for you your religion" revealed upon them, then they would have taken it as a day of Eid (celebration). Upon that Umar told the Jews that they didn't know that two Eids of Muslims were combined on this day. This verse was revealed in the 10 Hijri year at the incident of "Last Sermon" at the place of "Urfa" at the time of "Asr Prayer". There were 40 thousand companions with prophet Muhammad. And the holy prophet remained alive for 81 days after this incident.

Is there any book other than Quran which could be so much Incoherent?

For sure, even Bible is also incoherent at many places, but still itis tens of times better in incoherence than Quran and even a normal person could understand while reading it. But this thing is not possible with Quran, and a normal person is absolutely not able to understand it, despite the big claims of Muslims and Quran itself that Allah made Quran easy to understand for the people. 

What a pity that Muslims claiming such an incoherent book as the miracle. 

Actually, the biggest miracle is how billions of Muslims could consider such an incoherent book like Quran to be a miracle. 

External Link: The Truth About the Quran | Harvard Professor Shady Nasser