The debunkers of liberal Christianity are conservative Christians.
I've done a pretty good deal of debunking, and it covers several versions of Christianity that would qualify as "liberal" (ETA: and so, "non-conservative") But Politesse version is unknown, so I don't want to make a case in order to be told that that's not liberal (ETA: or not "non-conservative") Christianity. I need to know what he's talking about before I can make a case.
I had no particular variant in mind. Liberal Christianity is quite diverse (as is, for that matter, conservative Christianity). But since there have been liberal strains of the faith for a very long time, I was curious what, if any, arguments had ever been tailored in their direction. As for me personally, no one would consider me a good representative of any particular group I shouldn't think.
I think the
libera in liberal, when speaking of Christianity, is generally understood as
freedom from past orthodoxies, traditional political power structures, and the intellectual enslavement of the literalist hermeneutic with respect to the Bible.
Okay, so how about the following brief argument against the epistemic rationality of the belief that Jesus was morally perfect - which is held by liberal Christians like Randal Rauser -, or even good as a moral teacher (which is way more than would be needed to target most versions of liberal Christianity).
Argument?
Let's look at the Gospel. For example (there are other problems), in several passages, Jesus unmistakably endorses OT law, not necessarily for application to Christians (that is more obscure), but surely as the law given by a morally good all-powerful creator to the ancient Israelites. That shows a big error in judgment on his part, assuming that the Gospel's passages in question are accurate.
Is there a way around that?
The liberal Christian might say that those passages are not accurate precisely because in them, Jesus makes serious errors in moral judgement, which he would not. But then, what is the evidence that he would not? If it's based just on other passages in which Jesus does better, that's not a rational way of assessing whether he was good at ascertaining moral truth, but rather, an assumption beforehand.
The liberal Christian might alternatively argue that those passages have been mistranslated. But then, most liberal Christians simply do not have the knowledge to do the translation themselves, and there are a good number of people who can and disagree with such claims. What is the basis for the preference to exclude those passages?
Moreover, even if we exclude some passages, what remains also does not show any good evidence of someone better than we are at figuring out moral truths, as we can tell by looking at his claims. Now, the liberal Christian can say that the passages are obscure and we do not know what Jesus said, but then we have no good reason to believe he was a good moral teacher. In fact, most people aren't, so without any specific evidence that he was, one should hold that he probably was not.
Granted, the liberal Christian might have other claims; this is just a brief argument, but all such claims can be tackled, at least if they're clear enough to be understood.
I'm not sure that argument is concrete enough for the purposes of your question, but here's a narrower one:
Source:
http://ebible.org/web/MAT05.htm
Matthew 5 said:
27. You have heard that it was said, § ‘You shall not commit adultery;’✡ 28 but I tell you that everyone who gazes at a woman to lust after her has committed adultery with her already in his heart. 29 If your right eye causes you to stumble, pluck it out and throw it away from you. For it is more profitable for you that one of your members should perish than for your whole body to be cast into Gehenna.* 30 If your right hand causes you to stumble, cut it off, and throw it away from you. For it is more profitable for you that one of your members should perish, than for your whole body to be cast into Gehenna.
Here, Jesus implies that looking at a woman with lust is immoral, which of course depends on the case and often is not, but furthermore, he claims that people who behave immorally are at risk of being "cast into Gehenna", i.e., a horrific afterlife punishment, which Jesus implies (given context) is meted out by a morally perfect creator.
So, Jesus was very mistaken about morality in that passage. It did not end there, though:
Matthew 5 said:
31 “It was also said, ‘Whoever shall put away his wife, let him give her a writing of divorce,’✡ 32 but I tell you that whoever puts away his wife, except for the cause of sexual immorality, makes her an adulteress; and whoever marries her when she is put away commits adultery.
It is obviously not true that the only valid reason to leave one's wife is sexual immorality. Surely, attempted murder on the husband (for example) would count!
But let's leave that aside. There is a more fundamental problem with this passage: if a woman is abandoned by her husband, she does not commit adultery or behave immorally for that reason (which was implied by Jesus here) if she finds a new partner and gets married again (legally, it depends on the law of the land, but Jesus was talking about morality). The new husband does nothing wrong, either, for that reason alone (there might be other reasons, but not that).
So, once again, Jesus is quite mistaken in his moral assessments.
