Conventions require infinite-regress common knowledge to take root

Evidence

For a convention to take root within a community and become “regular” behavior, it must become part of common knowledge—where individuals know something, know that others know it, know that others know that they know it, and know that others know that they know that they know it, ad infinitum. Men show up in tuxedos to debutante balls whose invitations specify “black tie” thanks to widespread common knowledge about precisely what constitutes black tie and when to wear it. Moving the population to a new convention requires building new common knowledge. During the reversion of Okinawa from American control to Japanese rule, the island chain needed to coordinate a switch from American-style right-side driving to Japanese-style left-side driving. The government chose July 30, 1978, as the first day of left-hand driving and ran a multimillion-dollar “7-30” advertising campaign to raise awareness of the change in policy. The plan worked: other than a few bus accidents, drivers were confident that other vehicles would also be driving on the left from July 30 onward. — W. David Marx, Status and Culture, 126

Categorization

• DEFINE: Defines common knowledge precisely as iterative mutual knowledge that anchors what a convention is.
• CANDY: Okinawa’s coordinated July 30 1978 overnight switch from right-side to left-side driving is a delightfully concrete piece of trivia.
• XREF: connects to: Reflection cannot be modeled as knowledge of knowledge without regress; Deductive proof must rely on circular reasoning or endless chains — Bertrand Russell, History of Western Philosophy, 963; Communication codes require a taken-for-granted foundation immune to negation — Niklas Luhmann, Trust and Power, 688

Broader Connections

• Reflection cannot be modeled as knowledge of knowledge without regress #corroborates (0.85)
• Communication codes require a taken-for-granted foundation immune to negation #corroborates (0.80) — Niklas Luhmann, Trust and Power, 688
• Deductive proof must rely on circular reasoning or endless chains #expands (0.75) — Bertrand Russell, History of Western Philosophy, 963