[If] it's true that liberalism is an epistemology, then so too is conservatism -- one that, in its truest and noblest form, is far more open than liberalism to valuing the wisdom of the past as a sure guide to the present. It's weakness is that it can become fixated on tradition, and rigid in the application of its principles; conservatives can forget that theirs is not an ideology, but a temperament, and way of looking at the world -- in fact, a sort of epistemology. The problem with liberalism as an epistemology is that it can fall prey to being a prisoner of the present moment, and pays insufficient attention to the wisdom of the past -- this, as a result of its high idealism.
In their decadent stages -- and these things are cyclical -- both liberalism and conservatism forget that they are at their best limited epistemologies -- ways of seeing and evaluating the world that can only show us a partial truth -- and not ideologies. Epistemic humility is a virtue of which all sides have great need these days.