First off, I agree with ICANT when he talks about accepting your wife's wishes. If this is something she feels extremely attached to, it may not be something you should be trying to change about her. She is an adult, and deserves her own right to live (or die) however she feels is best.
However, I'm sure you understand that and yet you still came here for help. So, here's what I have for you:
1. "You cannot reason a person out of a position he did not reason himself into in the first place."--Jonothan Swift.
That is, I do not think that appealing to logic and reason will help you. She does not believe these things because they are logical or reasonable. She believes these things because she wants to, or she thinks she has to, or maybe it's just "the only way she's ever known". Find out her reasoning, then maybe you can understand her.
2. If you must fall back onto logic and reason. Try showing her how one of the things she believes is incorrect and see how she takes that in. The world being no older than 6000 years is an easy one.
Look through a nice thread by RAZD that goes through this in-depth, with lots of explanations and everything that's needed:
Message 1
But above all, respect her beliefs. To her, they are just as powerful as anything anyone says. If you even insinuate that her beliefs are inferior, she'll pick up on it and become defensive. Depending on how strongly she holds these beliefs, she may even think you're purposefully attacking her as a human being.
™ Version 4.2