It is often referred to as a rhetoric vs. dialectic divide, but even people tossing those two words around don’t really understand them, so let’s put it a different way with smaller words.
Conservatives are info junkies and like information for its own sake. Thus, they believe that bringing facts, data, information (even of the unfactual infotainment sort) into a discussion should be persuasive to liberals. They get very confused when liberals argue for x in one comment/remark and argue against x ten minutes later or six comments later in the same thread. But liberals aren’t interested in information, even if it confirms their biases. They are strictly about protecting their self-image as morally elevated and intellectually sophisticated.
Global warming/climate change is a great example. Most liberals don’t realize that the average skeptic’s position is not that carbon isn’t being emitted, but that the side effects (feedbacks) of the carbon emitting are not as large as the favored models claim. This is a more complex argument, but it’s one that is based on considering the data that is actually there regarding climate modeling and climate measuring/analysis. Liberals believe that global warming skeptics don’t believe carbon exists. Or even more simply that skeptics “hate science” or “don’t realize the SCIENCE is SETTLED”. And this is because such factless hilarity preserves their mental image of themselves as informed, morally suasive individuals who reasoned their way to the correct social display. The idea that the skeptic position is about confirming an anomaly’s existence rather than declaring the anomaly “settled” without such confirmation is anathema.
Liberals can’t talk to conservatives because conservatives want discourse and discussion (information exchange). Conservatives can’t talk to liberals because liberals want reassurance that they are following the right moral consensus (power exchange). Yep, I went there!