"In no sense is an argument a valid one if it is built upon the accuracy of what it is arguing is inaccurate. If the bible is false, then those entries are false, and cannot, therefore be used as part of your argument to show that the bible is false. You've created a loop. If those entries are true, then the bible is true, therefore your argument is false."
I understand this is known as the "Taxicab Fallacy" and is a favourite of Christian apologist and genocide and child-murder defender, William Lane Craig. For an excellent blog on this see The Fallacy of the "Taxi Cab Fallacy" by Plasma Engineer.
I thought it might be fun to see what we can do with this device which Christians and Muslims try to use to overcome the embarrassment of having holy books supposedly written/inspired by omniscient gods but which contain mistakes of fact or reason.
Imagine you're in court charged with a crime of which you are completely innocent and the prosecution have put up a statement by an eye-witness as evidence against you. The statement says the crime was committed on a Tuesday afternoon by a 6 feet tall, 220 lbs (15 stone 12 lbs if you're not American) woman with red hair and one leg. Your defence has pointed out that you are a 5 feet 6 inch male with black hair and the full complement of legs, and that the crime was actually committed on a Friday morning.
"Ah!", Say the prosecution, "but you can't use the errors in the statement to prove the statement is false because in no sense is an argument a valid one if it is built upon the accuracy of what it is arguing is inaccurate. If the statement is false, then those entries are false, and cannot, therefore be used as part of your argument to show that the statement is false. Therefore you have no grounds for questioning the accuracy of the witness statement".
"Got a good point there!", says your defence lawyer. "Can't dispute that logic!"
I wonder if my anonymous contributor would put his hands up and admit he/she must be guilty in that case because the witness statement is obviously true, or whether he would fire his defence lawyer.
I'm wondering is this 'logic' is just confined to written words or if it applies to other faulty things. In the UK we have a consumer-protection law called the "Trade Descriptions Act" which makes it an offence to lie about goods offered for sale. For example, it is illegal to state that a food item contains fewer calories than it actually contains, or that a washing powder makes your children glow in the dark when it doesn't.
I wonder if a rogue trader could get away with arguing that you can't use these errors as proof that his descriptions were wrong and misleading because, if the description is false, then those entries are false, and cannot, therefore be used as part of your argument to show that the description is false. The description is therefore true and not misleading.
I think if I took my car to the local garage because the lights didn't work and was told that the lights must be working because you can't use the fault to prove there is a fault with the lights, I might well use another garage in future.
As we can see, religious apologists have no worries about using the tactics of false witnesses, rogue traders or cowboy mechanics to pull the wool over the eyes of their followers who seem to have so much wool between their ears that this is almost too easy to do.