It's the only mechanism I've ever heard of for Darwinian evolution. Do you have an example of an evolutionist scenario which did not involve mutations?
They declare that something couldn't have evolved because it's too complex, so therefore it must have been designed. They don't offer evidence of design, design is their fallback position.
No they declare that it's irreducibly complex. That means that if you take away one part, the whole thing can't function. Evolutionary theory says that a large number of random mutations over long periods of time cause gradual changes in organisms. This poses a problem where there is a mechanism in a life form, like the bacterial flagellum, that is irreducibly complex. It has a number of distinct parts. I believe the link you supplied discussed this. In order for a mutation to be carried over from one generation to the next, it has to be beneficial in some way. That's how the entire species eventually gets the mutation. Perhaps the bacteria couldn't even have survived without it, but I'm not sure about that. It's extremely difficult to see how the flagellum could have been the result of random mutations. That's why the flagellum appears to be something where all the parts were put into place simultaneously, as would be the case if something were designed. That's why some evolutionists have proposed that during this long change period, the partly formed flagellum performed some other unknown funcion, so that it was retained from generation to generation, until it was completely formed, even though there's no evidence for it, and they can't say what this other function was. They don't seem to feel they need to provide that information.
You don't think God is outside of science?
He is outside of science, but the evidence of design isn't. One doesn't need to provide scientific evidence of God's existence to say things show evidence of design.
It is a problem, but processes to explain it, even if necessarily lacking in evidence (as you might expect with a continuum), are not inconceivable. For one thing you said it has to be beneficial in some way. Why would you think that? All that is required is that the lifeform with that property survive and reproduce. This can happen without the property being beneficial. I know of a guy with Huntington's disease. He reproduced and passed on the trait, but I fail to see how the trait confers a survival advantage.
I don't recall anyone hanging their hat on random mutations as the be-all and end-all of evolutionary mechanisms.
It's the only mechanism I've ever heard of for Darwinian evolution. Do you have an example of an evolutionist scenario which did not involve mutations?
No, but I was referring to "random mutations," which I would infer to be replication errors. I think viral-induced mutations are probably more important than replication errors. The human genome seems to be gunked up with ancient viral and bacterial genes.
They don't offer evidence of design, design is their fallback position.
No they declare that it's irreducibly complex. That means that if you take away one part, the whole thing can't function.
Well, that's Behe's claim, but irreducibility doesn't mean the complexity couldn't have evolved. It just means you don't know what the immediate precursor looked like. There may have been more parts, not fewer.
It's extremely difficult to see how the flagellum could have been the result of random mutations.
I agree, and I'm not qualified to explain how it might have happened. However, since you can't prove a negative, it boils do to opinion as to whether it could have happened or not.
You don't think God is outside of science?
He is outside of science, but the evidence of design isn't.
Behe's evidence for design is that "it couldn't have evolved." That doesn't do it for me. Your mileage may vary. :)