Steven Pinker at Persuasion:
“The Emperor’s New Clothes” dramatizes two features of common knowledge that make it not just a mind-blowing logical concept but a key to understanding human social life. One is that common knowledge need not be deduced from an infinite chain of musings about other people’s mental states (“I know that you know that I know that you know…”), which no mortal could ever think. It can be instantly imparted by a conspicuous event, like a plain sentence uttered in public.
The other is that the difference between private knowledge, even when widely shared, and common knowledge is not a mere logical nicety. It can unify knowers in coordinated action and sometimes explode a social status quo.
One of the best jokes from the vein of subversive humor in the Soviet Union has a man standing in the Moscow train station handing out leaflets to passersby. Soon enough the KGB arrest him, only to discover that the leaflets are blank sheets of paper. “What is the meaning of this?” they demand. The man replies, “What is there to write? It’s so obvious!” The point of the joke is that the pamphleteer was generating common knowledge.
More here.
Enjoying the content on 3QD? Help keep us going by donating now.