Com­mon Knowledge

Com­mon knowl­edge is in­for­ma­tion that ev­ery­one knows and, im­por­tantly, that ev­ery­one knows that ev­ery­one knows, and so on, ad in­fini­tum. If in­for­ma­tion is com­mon knowl­edge in a group of peo­ple, that in­for­ma­tion that can be re­lied and acted upon with the trust that ev­ery­one else is also co­or­di­nat­ing around that in­for­ma­tion. This stands, in con­trast, to merely pub­li­cly known in­for­ma­tion where one per­son can­not be sure that an­other per­son knows the in­for­ma­tion, or that an­other per­son knows that they know the in­for­ma­tion. Estab­lish­ing true com­mon knowl­edge is, in fact, rather hard.

See also: Public discourse

The Costly Co­or­di­na­tion Mechanism of Com­mon Knowledge

Ben Pace
15 Mar 2018 20:20 UTC
219 points
30 comments19 min readLW link4 nominations2 reviews

Un­rol­ling so­cial metacog­ni­tion: Three lev­els of meta are not enough.

25 Aug 2018 12:00 UTC
175 points
44 comments7 min readLW link3 nominations1 review

The Fear of Com­mon Knowledge

Eliezer Yudkowsky
9 Jul 2008 9:48 UTC
30 points
37 comments2 min readLW link

Scott Aaron­son: Com­mon knowl­edge and Au­mann’s agree­ment theorem

17 Aug 2015 8:41 UTC
15 points
4 comments1 min readLW link

You Have About Five Words

12 Mar 2019 20:30 UTC
78 points
37 comments1 min readLW link

There’s No Fire Alarm for Ar­tifi­cial Gen­eral Intelligence

Eliezer Yudkowsky
13 Oct 2017 21:38 UTC
293 points
67 comments25 min readLW link

Lo­cal Val­idity as a Key to San­ity and Civilization

Eliezer Yudkowsky
7 Apr 2018 4:25 UTC
205 points
63 comments13 min readLW link3 nominations5 reviews

In the pres­ence of dis­in­for­ma­tion, col­lec­tive episte­mol­ogy re­quires lo­cal modeling

15 Dec 2017 9:54 UTC
128 points
39 comments5 min readLW link

Prob­a­bil­ity Space & Au­mann Agreement

10 Dec 2009 21:57 UTC
43 points
76 comments5 min readLW link

FB/​Dis­cord Style Reacts

1 Jun 2019 21:34 UTC
77 points
79 comments5 min readLW link

Every­body Knows

2 Jul 2019 12:20 UTC
77 points
15 comments4 min readLW link

Speak­ing up pub­li­cly is heroic

2 Nov 2019 12:00 UTC
41 points
2 comments1 min readLW link