Belle Waring is getting a little tired of the "he knows where the ticking time bomb is" torture scenario. In her comments, Grand Moff Texan explains what's wrong with it (try here if that link doesn't work; they're switching blog hosts):

The manufacture of these scenarios is simply CYA masquerading as a challenge. It’s beyond a slippery-slope fallacy, it’s an imagined thing that has magically appeared at the bottom of a manufactured slope cunningly lubricated.

How do we know there’s a bomb and roughly where it is? How do we know that this is THE guy who knows (only somehow, knowing that, you don’t know what he knows)? How the hell did that happen? And how do we know that this electrode applied to that spot will PRESTO reveal the truth? How do we know he won’t lie to you or tell you what he thinks you want to know so you’ll stop? What color is his underwear? What did he have for breakfast? What’s his most traumatic childhood memory? How many fingers am I holding up? Does this look infected? Why is the sky blue? Why do bad things happen to good people? Why …

But Belle herself has her own way of pointing out the absurdity of the enterprise, postulating another scenario, only slightly more far fetched, in which it is necessary to torture an innocent three year old child who knows absolutely nothing, for the sole purpose of appeasing alien genocidal freaks, to be offered as Swiftian "proof" that hey, torturing innocent kids is just dandy.

Yet in comments, someone else rebukes her:

Belle, I don’t think reductio ad absurdam is a proper argument. I remind you of the juristic truism that hard cases make bad law.

Thereby demonstrating the pitfalls of this style of argument even better, by falling in. He's bought into the "ticking time bomb" scenario so thoroughly that he can't conceive of it as the kind of hard case which does, in fact, make bad law...