We now all know that proof won't set us free

This assertion by Joan Walsh triggered an off-center thought:

President Obama is right not to release photographic "proof" that Osama bin Laden is dead. There's absolutely no upside: The lunatic fringe will still doubt the evidence, and gruesome corpse photos run the risk of creating a backlash against bin Laden's killing that doesn't exist so far.

The thought: birtherism has corrupted our collective sense of what constitutes proof.  It's now a near-universal assumption that a vocal minority will reject demonstration of any fact, now matter how definitive by any reasonable standard. (As Gideon Rachman put it, "After the controversy over Obama’s birth certificate, why not have one over Osama’s death certificate?") This has always been true to a degree: I remember my mother telling me that there were people who did not believe that Americans landed on the moon in 1969.  But the size, noisiness and impact of what were once regarded as lunatic fringes has made them impossible to ignore.