Some conservative fellow wrote a piece a while back using that phrase, "epistemic closure," to describe his fellow conservatives. It sparked a grand discussion. The phrase is meant to explain how it is that whole legions of alleged well educated individuals lock themselves into intellectual absurdities, such as the falsity of anthropogenic climate change, that lowering taxes on the rich increases tax revenues, that conservative and industry-friendly health reform proposals are socialist, communist, or fascist, and so forth.
There is an entertaining discussion of this on Crooked Timber (first here, then here, then here), although the author (John Quiggin) prefers "agnotology" to "epistemic closure" (with good reason, there's a book on the phenomenon). Go read Quiggin's posts. The second of them asks the question as to whether the left is guilty of the same degree of agnotology. His answer is no (I think he's right about this–in the long comments section, no one could satisfy the accusation of tu quoque).
So what does he recommend? This:
And as the agnotology/epistemic closure debate has shown, awareness of these facts is increasing. As they become more and more evident, there has been a steady trickle of defections from the intellectual apparatus of the right, some of them quite surprising. With the facts now openly admitted, we can expect to see more.
What does this imply for the left, and particularly for intellectuals on the left? First, as I’ve said, I think it spells an end to any idea that there is value in engaging in discussion with smart people on the other side. It’s impossible to be a smart (and honest) movement conservative, since you have to assent (overtly or tacitly) to all sorts of stupid and dishonest things. Take, for example, a discussion of health care. Whatever arguments someone opposed to Obama’s policy might come up with, if they line up with the Republican position, they are relying on lies about death panels and socialised medicine, repeated by their most prominent leaders, to carry the day. There is simply no point in pretending to engage such a person in honest debate.
Indeed. I agree. But ignoring them won't get us anywhere. They and their silly ideas dominate what passes for public discourse in this country. Besides, ignoring them plays right into their driving narrative: elitist liberals look down on us.