But still doesn't change anything that was done, said or felt at any time before that knowledge was obtained. All that changes is the hindsight view of it.
This is a very narow account of the case.
I'm going to present a stark example which I hope isn't offensive:
A sleeps with
B who is (as far as
A knows) a stranger.
A subsequently learns that
B is
A's sister.
A thereby learns
that A has committed incest.
A may or may not care deeply about that - the world is full of different moral perspectives - but I think for most people there is no doubt that
A did something when sleeping with
B that is different from what
A thought was happening.
(A movie I watched recently in which just this scenario occurs: The Curse of the Golden Flower. Another well-known historical/fantasy film where something similar happens: Excalibur, where Arthur sleeps with his sister who is pretending to be Guinevere by dint of shapechanging magic - thereby replicating the very magical trick that led to Arthur's conception.)
Learning that one committed incesst isn't just forming a hindsight view. It's learning the nature of an act that - at the time the act was committed - one completely failed to understand had taken place.
The same thing can operate in RPGing. I know, because I've experienced it in two of the three campaigns that I mentioned as bad ones, that I therefore left/helped kill off, in my first post in this thread: the GM introduces new fictional content which completely changes or even invalidates the meaning of the established fiction, and thereby wrecks the game.
One example is the McGuffin quest - as players we have our PCs go along with the patron's McGuffin quest because it's clear that
this is the adventure the GM has on offer (our PCs have no deep narratiave reason to do this thing - there's a surface veneer of salary and expedience, which papers over the true reason which is that we're playing the GM's adventure). So it's a story about a group of McGuffin questers - pretty stock standard RPGing stuff. Then the GM unilaterally decides that the patron betrays us, thereby changing it into a story of a group of patsies (both PCs and players!) tricked into doing something with no good reason to do so. The meaning of what had happened is completely changed. And to tie it back to "character concept", through no choice or fault on our part - because as players we had no meaningful choice not to send our PCs on the fetch quest - our PCs have been revealed to be not the semi-competent fetch questers we had envisaged them as, but as a group of duped losers. All through GM fiat.
As I already said, the game ended at that point. Not because the GM ended it, but because a critical mass of players (not just me) were not interested in that sort of play experience, of having the meaning of characters and events unilaterally rewritten by the GM so as to invalidate - from the narrative and thematic point of view - the choices that we had made while playing.
I won't spell out the other example in so much detail, but the short version is this: when the GM decided, unilaterally, that we all travelled 100 years into the future, thereby invalidating all the interesting intra-party stuff that had been built up about our mutual connections both among ourselves and to places and events in the gameworld, and also how those and we related to a prophecy, he likewise killed the game.
we're not talking about what one might think on seeing Star Wars 4-5-6 for a second or third or seventieth time, when that meta-knowledge is already in the audience's consciousness. We're talking about the viewer's first time through, without the benefit of hindsight, as we will always be* in an RPG discussion.
A player is not a viewer. A player is a participant in the game, who is helping establish fiction, including especially fiction about his/her PC. If the GM unilaterally decides that I (as my PC) am committing incest because the NPC I'm in love with is secretly my sister; or unilaterally decides that I'm supporting a serial killer because dear dad to whom I'm remitting back some of my hard-won gold pieces is in fact a serial killer; then the GM is unilaterally changing my character concept and the meaning of my action declarations.
If someone
does play the game purely as viewer rather than participant; or if their
participation is confined to purely tactical or puzzle-solving aspects of play; then the response might be different. I'm not such a player.
I feel this goes very clearly back to some posts [MENTION=16586]Campbell[/MENTION] has made about the role of the players in contributing to the fiction that is the content and focus of play.