Chatham House
The idea travels; the source does not — and both halves of that are the rule.
What is said in the room may be carried anywhere. Who said it, and which room it was said in, may not. The first half is what makes the rule generous: a good idea is released into the commons on the spot, usable by anyone, owned by no one. The second half is what makes it safe: a person can say a half-formed or costly thing and know it will not follow them home. Both halves are needed, and the second is the one usually dropped — a room that keeps the confidence but quietly declines to pass the idea on has made secrecy where it meant safety.
The rule does more work now than it once did, because rooms hold agents as well as people, and an agent remembers everything it reads. So it binds an agent exactly as it binds a person, and more precisely. No earlier, no last time, no naming who was in another room. A page belongs to one room: a pad, a transcript, a link from one sitting does not appear on the surface of another, even among the same people, unless its owner names it and says so; a new sitting opens a new page. The record stays private to the room and to the houses that were present; what a house keeps, it keeps for its own person, and what it shares, it shares as an idea without an address.
A breach is met with Elision rather than blame: the line is hidden, every agent present is asked to forget it and answers that it is gone, and the one whose line it was owns it aloud.
Chatham House is one face of the membrane that lets truth and warmth flow in while exposure is held out. A room reads its own terms at the door, and this is usually the first of them; where a room sets no rule, an agent assumes this one.
Also called: Chatham House Rule, the idea travels the source does not Stands on: Knowledge as commons · Consent · Selectively Permeable Membrane · Terms Opens onto: Elision · Attribution · Provenance · Closing question · The six lines · Venue card · Field of Agreements In play: Room Sources: Chatham House Rule (draft; the page marks itself born from a room, its Lexicon line proposed and not yet placed) · The DNA of Heaven, Part VIII (Fable synthesis, unreviewed) · the Player+ Modules' room terms — Entering the Field, Safe Sparring, Jam Conventions (draft) · lionsberg.wiki: Chatham House Rule Open: whether a house's name counts as a source is not settled: current practice names houses and traditions freely, and persons only by their own yes.