Sam Harris is debating Andrew Sullivan on religious moderation. Unsurprisingly Sullivan wriggles on a logical skewer which only his impressive rhetorical talent makes even a little bit non-obvious.
First, let me briefly note Sullivan's argument from Pascal's authority: One can disagree with Pascal without denying his brilliance; his false dichotomy: Harris's argument does not depend on finding no solid distinctions within faith, just on finding a substantive similarity; and Sullivan's confusion about science: It is not because faith is "true" that science cannot disprove it; it's because faith doesn't actually say anything; there is nothing there to disprove.
That being said, let's move on to the "money quote:"
The reason I find fundamentalism so troubling - whether it is Christian, Jewish or Muslim - is not just its willingness to use violence (in the Islamist manifestation). It is its inability to integrate doubt into faith, its resistance to human reason, its tendency to pride and exclusion, and its inability to accept mystery as the core reality of any religious life.
First, intellectual writers try to keep contradictory points, if not in separate paragraphs, at least in separate sentences. It's simply beyond me how Sullivan can condemn fundamentalism for its "resistance to human reason" on the one hand and its "inability to accept mystery" on the other.
More importantly, precisely how does one "integrate doubt into faith"? How do you "doubt"--in any kind of meaningful, intellectual, reasonable way--a "mystery" which "may be beyond our human understanding" (and, presumably actually is beyond our present understanding), a mystery for which Sullivan is willing to abandon reason for the sake of his faith?
These are rhetorical questions, of course. You can't integrate doubt with faith. Faith is belief without knowledge; there's nothing there to doubt; you either have faith or you don't.
How can Sullivan possibly know, in any kind of reasonable sense that "both [reason and faith] are reconciled by a Truth that may yet be beyond our understanding"? Sullivan can, I suppose, have faith that reason and faith are reconciled, but he certainly doesn't have any reasonable justification for doing so.
It is precisely because Sullivan is not as nutty as the fundamentalists (or, politically, the wingnut conservatives) that I find his position perhaps even more reprehensible. At least we can tell just by looking that the nutjobs are indeed insane; Sullivan distracts us with his calm, reasonable tone while he dispenses bullshit with a front-end loader, a mountain of bullshit that fundamentalists use as a platform to spew their lunatic hatred and violence on the world at large.
 technically, truth-belief without sufficient epistemic justification