Are Christians the Best Argument Against Christianity?

According to The Confident Christian, Christians themselves are “the best argument against Christianity.” The author sums up the argument as follows.

Noted Christian apologist and author Ravi Zacharias says the one question that has haunted him the most throughout his ministry was asked by a Hindu acquaintance: “If this conversion you speak about is truly supernatural, then why is it not more evident in the lives of so many Christians that I know?”[6] In other words, a God who is said to transform should produce people with transformed lives.

This apparently very visible missing element in the Church today has been pointed out by famous atheists such as Frederick Nietzsche who once remarked, “I might believe in the Redeemer if his followers looked more redeemed”, and Karl Marx who turned away from religion when he saw his Jewish father abandon their faith in favor of joining the Lutheran church simply to help his business grow.

This argument reminds me of Paul Draper’s argument, in his debate with William Lane Craig, that the “meager moral fruits of theism” are evidence favoring naturalism over theism. Here is a summary of that argument (in my words, not Draper’s).

The moral fruits of theism are meager at best: theists do not seem to live more moral lives than atheists. Neither church history nor Draper’s personal experience support the claim that theists are morally superior to atheists. On the assumption that theism is true, one has reason to believe that theistic belief has significant moral fruits, that worshipping God is a source of moral strength. Thus, on the assumption of theism, the fact that theists do not seem to live more moral lives than atheists is surprising. On the assumption that atheism is true, however, this is not surprising. On atheism, believing in God would not make people morally better.

Draper now believes that there is insufficient sociological evidence to prove that theists do not live more moral lives than naturalists. I have chosen to follow Draper’s lead, so I do not include this argument in my cumulative case for naturalism.

I shall call Draper’s argument against theism the “argument from the meager moral fruits of theism.” And I shall call the version which focuses specifically on Christianity the “argument from the meager moral fruits of Christianity.”

Let us now return to the claim made by the Confident Christian. Do Christian themselves provide the “best” evidence against Christianity? I guess this all depends on what one means by “best.”

If “best argument” means something like “the argument with the most evidential strength,” then I’m not sure I agree. As a Bayesian, I equate “evidential strength” with the ratio of the explanatory power of two competing hypotheses with respect to a piece of evidence, what is also known as the Bayes factor, likelihood ratio, or boost factor.  If B is our background information, E is our evidence to be explained, and H1 & H2 are rival explanatory hypotheses, then the Bayes factor is:

Off the top of my head, it seems to me that the Bayes factor for several other items of evidence in my cumulative case for naturalism are much higher than the Bayes factor in the “argument from the meager moral fruits of Christianity.”

If, on the other hand, by “best argument” one means “the argument with the most emotional or rhetorical appeal,” I’m still not sure the argument from the meager moral fruits of Christianity is the “best.” I could be wrong, but it seems to me the argument from divine hiddenness is stronger.

What do you think?

(HT: BK at Christian Cadre)