Carlo Strenger has written a good article on enlightenment values on Comment is Free:
…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 has been ignored by both 20th century secular ideologues, religious authorities, and more recent fanatics, 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. As Strenger puts it:
At its best, enlightenment creates the capacity for irony and a sense of humour; it enables us to look at all human forms of life from a vantage point of solidarity.
A further mistake on the part of humorless fanatics everywhere is to assume that there can ever be one, and only one, 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 cave.
And so human beings are prone to error. There’s no problem with this, as failure teaches us more than success.
This notion was articulated by Karl Popper in the 20th century: it is the idea that you can never conclusively prove that an idea is correct, but conclusively disprove an incorrect idea.
And so human knowledge grows and the enterprise of civilization advances, one laughter-inducing blooper at a time.