I love this quote from Thomas Sowell's A Conflict of Visions: Ideological Origins of Political Struggles :
It is precisely the correctness or incorrectness of particular beliefs about social causation that requires scrutiny - a scrutiny arbitrarily barred by the phrase "value premises." ("Value premises" are, ironically, a sort of property right in conclusions, not to be trespassed on by evidence or logic.) [pg. 238]
So cool: "a property right in conclusions". Too common though: isn't this really what the OWS supporters were claiming when they boycotted Greg Mankiw's class without even listening to what he had to say?