"We are told that we live in a post-truth age. When the facts get in the way, we turn to 'alternative facts' that serve our purposes. Rather than listen to another point of view, we focus only on arguments and talking points that support our ideology. Not everyone is like this, of course, but it seems to capture the tenor of the times. Worst of all, it exacerbates the polarization that so many worry about, because we can't find common ground. The root problem, in my view, is a gradual abandonment of rationality. We can't reach consensus because we no longer acknowledge a rational basis for resolving disputes. Ethics was an early casualty of this retreat from reason."