When is Torture Justified?

It is hard to know how to continue a rational discussion with someone who acknowledges a contradiction and then shrugs it off with "it's fine with me".

But let's just explore the "torture warrant" scenario for a moment.  Suppose such a warrant were issued against Breivik, given the "probable cause" that he had boasted about other cells.  Now, I'm pretty sure the first words out of his mouth under torture, or indeed the mere threat of it, would be to deny that such cells exist and admit that his claims were just empty bravado.  Instantly, the "probable cause" evaporates, doesn't it?  The only "witness" who ever offered evidence of its existence has just recanted his testimony.  Can we still be confident that he ever had such information?  If not, is the warrant still valid, and do we torture him anyway?

Now let's suppose that these "cells" are nothing more than like-minded (i.e., mentally unstable) buddies of Breivik who brag and posture like him, but have no serious intention of going through with it.  What do you suppose will be their reaction upon hearing of the horrific treatment of their comrade by the evil Norwegians?  Might they be provoked into committing the very acts that you so fear?

And what of the thousands of other potential radicals, extremists and assorted nutcases in Norway and elsewhere around the world?  You probably know how horrific crimes tend to inspire "copycats".  How many other acts of torture or extreme violence might be spawned by your desperate attempt to extract non-existent information from this guy?

We're all afraid of senseless violence, and rightly so.  As I said, true courage lies in not giving in to fear, but in standing firm in your principles, knowing that in the long run they are always the best guide.  That's the whole reason we have principles in the first place.  If you can so easily toss them aside just because you are frightened, then they are worthless.

P.S.: Regarding isolation - yes, the Golden Rule still applies.  I can see the wisdom in holding Breivik in isolation, and I fully accept the right of a foreign government to do the same to me (with access to legal counsel and under otherwise humane conditions) for a reasonable period if they suspect me of a serious crime, and have good reason to think it necessary.