Hardly any of the attempts to explain away the errors seem at all plausible to me, so I often wonder if Muslims are as satisfied with them as they act. Something that should make them worry is a twist on these arguments: Rather than try to prove that something is an error, ask why there are so many things that seem to a reasonable person to require implausible acrobatics to explain away. Why are there so many verses that sound geocentric, and nothing clear to counter that impression, if this is the work of a being capable of perfection? The one time I argued with a Muslim and used this argument, and I included lots of geocentric verses, they stopped replying.
I think one of the biggest problems (an imperfection) is having set prayer and fasting times around sunset and sunrise, which isn't suited to a globe with populations at high latitudes, but smacks of flat-earthism where it''s the same time for everyone. They need some very contrived extra rules to help Nordic countries, Antartic base scientists etc.
Here's a novel error I noticed myself:
53:1 By the Star when it setteth,
56:75 Nay, I swear by the places of the stars [mawaqi is an ism makan - a noun derived from a verb and meaning the place where it happens - in this case the place of falling]
These suggest there are actual places where the stars set. Unlike the sun, the apparent places on the horizon where stars rise and set do not change perceivably throughout the year (it's the times that change as the year progresses, and even that is just a matter of perspective depending where on the globe you are observing the star).
Here's a couple where the attempts to explain away are especially futile:
A big error, but seldom noticed by Muslims due to generous translations and claims on dawah sites, is that semen is gestated in the womb (put in a safe place). See 23:13 (nutfah) and 77:20-22 (despised water).
There is no evidence that nutfah was used for anything other than liquids. It very suspiciously fits the popular Galenic/Hippocratic/Talmudic idea that the embryo starts off as semen before taking other forms. See my article about
nutfah for details.
The best the apologists can do is to fabricate dictionary definitions or misleadingly quotemine or lie about hadiths to make it sound like nutfah is a reasonable word for a sperm/ovum/zygote/blastocyst.
A perfect author would not be so short-sighted to lose future customers by making the Quran seem to contain the ideas of the time by using this word.
My favourite though has to be the guy who Allah helps to reach the setting place of the sun and finds it setting in a muddy spring. I looked in detail at every attempt to explain this away (that it just means west, that he reached the time of sunset, metaphorical language, whole story is allegorical etc.) and they all have severe problems.
Here's a shorter version of the article I wrote about it.
The easiest point to make on that one though is just to ask why Allah would use wording that sounds like popular legends and poems of the time about the sun setting in a spring, such that people took it literally (evident from hadiths, tafsirs). Why expose the Quran to such doubt when it could so easily have been avoided?