Glenn Greenwald writes:

In fact, one could reasonably make the case that those whose thinking is shaped by unexamined, unacknowledged assumptions are more biased than those who have consciously examined and knowingly embraced their assumptions, because the refusal or inability to recognize one’s own assumptions creates the self-delusion of unbiased objectivity, placing those assumptions beyond the realm of what can be challenged and thus leading one to lay claim to an unearned authority steeped in nonexistent neutrality.

Greenwald discusses objectivity in light of the vice-presidential debate.