On Sun, 28 Oct 2018, Reuben Staley wrote:

 8121  G.                  3.0   Retroactive Documents
PRESENT. There are arguments for and against doing this and I am not convinced which way to go.

This was a result of a discussion between me and G. on a rather subtle point, where it took a while for me to convince him, so given the proposal has no comments, I'm not surprised that some voters don't see why it's needed.

Ratification _simulates_ retroactive modification of the gamestate, but it's written to achieve this without _actual_ retroactivity, with a two-level mechanism:

* Find a _minimal_ hypothetical modification to the gamestate that would
  have made the document's claims true if they had been applied _at the
  time it was published_.
* Then fast-forward from that hypothetical modification to the present,
  and in the present change the gamestate to what it would have been if
  the hypothetical modification had been done in the past.

This mechanism works well when applied to documents that describe "concrete" gamestate _at the moment they are published_, because at that moment the minimal change needed to make them true is generally obvious.

But not all documents happen to be of this kind. Sometimes a CoE results in a revision where the Officer publishes a new report, but with a note that it does not include changes since the previous report. And sometimes, like the hypothetical that started this discussion, someone attempts to correct an error in the past by publishing a _new_ document speaking _about that past_, and then ratifying it.

However, with the current wording of ratification rule, this can have strange effects, because there is now time for _changes_ in game state to happen between the time the document speaks _about_, and the time it is _published_:

Time A: G. has 50 coins
Time B: G. uses coins for scam (needs at least 40), massive follow-on game
Time C: Report (or possibly anti-scam document) published, says G. had 10
  coins at time A
Time D: Report ratified somehow

By the current Ratification rule, the "minimal change" is calculated at time C, _after_ the massive game changes caused by the scam.

At that time, is a _smaller_ change to say that the scam _worked_, say by having G. lose 40 coins at time A, but then regain 30 some time before time B. Therefore, by the wording of the Ratification Rule, it does _not_ cancel out the scam, as one would otherwise intuitively expect.

G.s proposal adjusts ratification so minimality is calculated at time A, instead, where again the required change is obvious and has the intuitive result of cancelling the scam.

Side note: The trouble would be even more severe if G.s scam involves rule changes, because then the intuitive (but huge) modification at time C would need to cancel those, _without_ the document saying so, which the ratification rule _also_ explicitly forbids.


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