In practice, though? No one persuades anyone on the basis of facts anymore because all of us are emboldened to reject facts that do not fit comfortably into our understanding of how the world should be organized. If a good guy turns out to be bad, he must have been a bad guy all along. If one bad guy decides that he agrees with me about the other, much worse, bad guy, he is a good guy, at least for now. Climate change is going to kill us all in 10 years. Climate change is fake. Abortion is a safe medical procedure and a constitutional right. Abortion is murder. The caravan is going to murder us in our beds. There is no caravan. Trump is a Russian agent. Trump is Cyrus the Great.

This epistemic disjuncture — between right and left, Trump and #NeverTrump, pro-life and pro-choice, FOX and MSNBC, even progressive and liberal — is worrisome. How are we supposed to have reasoned debates if we are not arguing about the same facts? Without a common frame of reference, politics devolves into shouting: endless imputations of bad faith and mutual anathemas and suggestions that this or that group is utterly beyond the pale. Which is all fine and dare I say, occasionally entertaining.