By Brooke Gladstone at Slate
http://www.slate.com/articles/news_and_politics/politics/2017/05/why_trump_lies_it_s_not_to_hide_the_truth_it_s_to_alter_reality.html
"SNIP................
Consensus is the bedrock of democracy. For differences to get resolved in a properly democratic fashion, there needs to be agreement over the terms of the debate. Interlocutors must be aware of their shared rights and responsibilities, and they need to be capable of proceeding from a common set of facts and premises.
When political actors can’t agree on basic facts and procedures, compromise and rule-bound argumentation are basically impossible; politics reverts back to its natural state as a raw power struggle in which the weak are dominated by the strong.
Even if each of our realities is unique, our common cultures and environments ensure that we share some fundamental principles. That is what enables consensus, and that is what is under attack.
By degrading the very notion of shared reality, Trump has disabled the engine of democracy. As Resnikoff wrote: “When the truth is little more than an arbitrary personal decision, there is no common ground to be reached and no incentive to look for it.”
................SNIP"