"PHILOSOPHICALLY SPEAKING...":

According to a law professor at the University of Dayton, growing epistemic pluralism – wide-ranging views on empirical facts – and disagreements over epistemic dependence – who constitutes a trusted source of information – are contributing to polarization in American political life. 

"Without the government or an official church telling people what to think, we all have to decide for ourselves – and that inevitably leads to a diversity of moral viewpoints. ... [T]he same is true of beliefs about matters of fact. In the U.S., legal rules and social norms attempt to ensure that the state cannot constrain an individual’s freedom of belief, whether that be about moral values or empirical facts. This intellectual freedom contributes to epistemic pluralism. ... Another contributor to epistemic pluralism is just how specialized human knowledge has become. No one person could hope to acquire the sum total of all knowledge in a single lifetime. This brings us to the second relevant concept: epistemic dependence. Knowledge is almost never acquired firsthand, but transmitted by some trusted source. To take a simple example, how do you know who the first president of the United States was? No one alive today witnessed the first presidential inauguration. You could go to the National Archives and ask to see records, but hardly anyone does that. Instead, Americans learned from an elementary school teacher that George Washington was the first president, and we accept that fact because of the teacher’s epistemic authority. There’s nothing wrong with this; everyone gets most knowledge that way. There’s simply too much knowledge for anyone to verify independently all the facts on which we routinely rely. ... However, this raises a tricky problem: Who has sufficient epistemic authority to qualify as an expert on a particular topic? Much of the erosion of our shared reality in recent years seems to be driven by disagreement about whom to believe."
theconversation.com/why-cant-americans-agree-on-well-nearly-anything-philosophy-has-some-answers-193055