Noah Rothman: A Funny Thing Happened On The Way To "Epistemic Closure"

That's not 'epistemic closure' in the philosopher's sense, but in the handy but-not-actually-what-the-term-means sense that popped up like ten years ago in the blogosphere.

Anyway.

I have no idea whether he's right when he says that conservatism is particularly dynamic right now. 

But there is absolutely no doubt that the progressive left is as dogmatic as any political movement I've seen in my entire life in this country. It's closed-minded to the point of self-parody.

How'd this happen?

That question can be answered at a couple of different levels, but here's my own--hence my favored!--hypothesis:

The more radical a movement becomes, the harder it is to rationally defend its doctrines. Hence the more tempting it is to "win" by non-rational means--e.g. shutting down debate. One way to shut it down is to shut it down internally: self-police your membership to tamp down internal doubts/criticism. Check! Progressive left's got that covered, obviously. The other way is to attack outsiders who raise doubts. Check again. This has advantages (from the perspective of the dogmatic cultist) not just externally, but internally, too: the fewer challenges your Believers hear from outside, the less they themselves will be motivated to raise them internally.

This is Peirce's method of tenacity + method of authority. (Actually, you also find a version of his "a priori method" on the left these days. Progressives love spinning out just-so stories...)

At any rate: it's an epistemic/political strategy: when you can't win debates, your options become limited. An obvious alternative is: shut 'em down. Shut down other views successfully enough, and yours becomes the last view standing.