From watching numerous debates, I've noticed a common tactic. In response to a strongly reasoned argument against the credibility of Christian beliefs, the Christian shows (rightfully) why the argument fails to disprove his Christian beliefs. The Christian is absolutely correct, the atheist's argument did not disprove Christian beliefs. The Christian thus deems the argument a failure, the debate rolls on, and the crowd is impressed by the intellectual robustness of Christian belief.
But what just happened?
While it appeared persuasive, the Christian has simply fallen back on the fact that no belief (true or false) can ultimately be disproven, whether it's belief in Jesus or mermaids. I call this type of defense the "failure-to-disprove" defense. While sometimes hard to recognize, the failure-to-disprove defense has a couple common signatures:
- Imaginatively inventing some scenario (usually involving the supernatural) in which one's questionable beliefs are not disproved despite the strength of an opposing argument.
- Appealing to epistemological limitations, "how do we really know anything for sure?!" to avoid disproof.
Either way, the defense boils down to the fact that the argument failed to ultimately disprove the belief. This fact can be used equally to support Christianity, atheism, Heaven's Gate, and Santa Claus.
For example, let me apply the failure-to-disprove defense to support the existence of Santa Claus. Watch the scenarios I invent to maintain my prior belief in Santa Claus despite the onslaught of reason:
Santa-skeptic: "You say Santa is fat, and yet he fits down tiny chimneys."
Santa-believer: "Well, he has extraordinary contortion powers of course. Your argument fails."
Santa-skeptic: "OK... His home cannot be seen at the North Pole."
Santa-believer: "Have you searched every inch of the North Pole? Besides it's probably underground. Your argument fails."
Santa-skeptic: "Even underground, it would be detectable by thermal sensors."
Santa-believer: "Well, again, Santa is no ordinary being. He's fully spiritual in addition to being human. His house isn't necessarily detectable by unbelievers in the physical realm. That'd obviously make things too easy for those who want on his "nice" list out of selfishness. Your argument completely fails to disprove Santa."
Santa-skeptic: "OK... How can he possibly visit every house in one night?"
Santa-believer: "Again, he's extraordinary. And besides, I'm not a fundamentalist, I believe he could have his elves help out. Just because you can't fathom it, that does nothing to disprove my beliefs."
Santa-skeptic: "I know for a fact that my childhood presents came from my parents."
Santa-believer: "But how do you really know that? You can't absolutely know that. Parents have typically lost their Faith in Santa and wouldn't believe even if they saw him or his gifts. And besides, I wouldn't put it past Santa to work through unbelieving parents, instead of his elves, to deliver exactly the gifts Santa had in mind for the believing child. Your argument fails."
As you can see, the Santa skeptic can never win. The believer is deeming every anti-Santa argument a failure, because each one ultimately failed to disprove his belief in Santa Claus. Well, unfortunately for the believer, failure-to-disprove doesn't change the fact that each anti-Santa argument was quite good, and ultimately on-point.
For a real-life example, see William Lane Craig employ the failure-to-disprove defense against Peter Atkins here: http://www.youtube.com/watch?v=gkBD20edOco
Atkins makes a couple decent arguments against Christianity (though he's extreme in his view of what science can account for), namely:
- Science is able to explain things that religions attribute to God
- Humans have desparate motives for belief in God (ie fear & hopelessness)
The failure-to-disprove tactic is seldom necessary for truthful propositions. For example, I'd never need this tactic if I was trying to convince a skeptic that France is a real place. I'd never need to resort to saying "your argument fails to disprove my proposition that France exists." To do so would be to neglect the wealth of actually-potent arguments and evidence that is available.
The failure-to-disprove tactic is low-quality because it can be used equally to support any silly belief. The tactic reveals nothing about the potency of the opponent's argument, as every argument ultimately fails on some level. When someone relies on the failure-to-disprove tactic, they're unwittingly placing their belief on a reasonableness level with Santa Claus, as the same tactic is used to support both beliefs. Either they're neglecting the better arguments that could be made, or there aren't any better arguments for their belief.