...the Enlightenment has created an idea of immense importance: no human belief is above criticism, and no authority is infallible; no worldview can claim ultimate validity. Hence unbridled fanaticism is the ultimate human vice, responsible for more suffering than any other.
it applies to the ideas of the Enlightenment, too. They should not be above criticism, either. History shows that Enlightenment values can indeed be perverted into fanatical belief systems. Just think of the Dr Strangeloves of past US administrations who were willing to wipe humanity off the face of the earth in the name of freedom, and the – less dramatic but no less dismaying – tendency of the Cheneys and Rumsfelds of the GW Bush administration to trample human rights in the name of democracy.
As one of the commenters points out, the profound principle that both 20th century secular ideologues and religious authorities throughout history have ignored, is that of always bearing in mind the possibility you might be dead wrong.
The healthy human response to harmless error or misunderstanding is to have a laugh. Thus error is highlighted for all to see and forgiven by all parties.
A further mistake on the part of humorless fanatics everywhere is to assume that there can ever be one, insoluble, and eternal truth. It may be that such a thing exists, but it is likely to be beyond our capacity to discern its true form from the vague shadows on the walls of our epochal cave.
And so human beings are prone to error. There's no problem with this, as failure teaches us more than success.
This idea was only properly articulated by Karl Popper in the 20th century: it is the idea you can never conclusively prove that an idea is correct, but rather disprove false ideas.
And so human knowledge grows and the enterprise of civilization advances, one laughter-inducing blooper at a time.