I currently 'have' a minor SF setting, for which there exists a few short stories, comics, pictures, and the like, created by a variety of artists and authours. I'd like future contributions to be as rationalist as possible - for as many characters within the setting as possible to be Rationalist!Heroes, or even Rationalist!Villains. Do you have any advice that might help me try to nudge the various amateur artists and authours involved in that direction?
(In case you're curious, the setting's current reftext is here. The basic underlying question I'm basing it around is, "As technology advances, it becomes possible for smaller and smaller groups to kill more and more people. How can society survive, let alone develop, when individuals have the power to kill billions?" So far, most of the creations have been developing the overall background and characters, rather than focusing on that question directly.)
Check the plots for Contrived Stupidity Tropes: the Generalized No Idiot Ball Principle.
What's with everyone using exclamation marks in the middle of words? Isn't that what spaces or hyphens are for?
It's a fanfiction convention - descriptor!Character is the standard version.
But doesn't English already have a perfectly good convention? Why write "invisible!Batman" when you can write "invisible Batman" and be understood by Muggles?
Because with fanfiction!English, you get to have neat jargon that makes you feel like part of an in-group. (Which is not a notion to be dismissed out of hand)
Is that meant to be a justification or merely an explanation?
Also, often certain variants of description!Character take on a life of their own, outside of the generic "description Character" description.
For instance, fat!Vriska draws some of her vindictiveness from being overweight, whereas a fat Vriska may not.
Part of a justification. (Perturbation's answer is also relevant)
I think it's also meant to signify either the primary defining feature of the character or the way that the theme of the fanfiction differs from the source. You would probably not write a story about invisible!Batman (assuming that can't be fleshed out to to be the actual theme of a story), but instead (say) Dark!Batman for a story that is darker than normal Batman stories (Batman himself need not be dark; perhaps Barbara Gordon decides killing the Joker through bludgeoning him to death publicly in front of city hall is the best way to restore order to Gotham).
Alternatively, you could write a story with Detective!Batman for a story that focuses on Batman's use of detective work (CSI-style fic) to try and solve mysteries. The ! tag is acting as little more than "Detective Batman" would, but with the understanding that Batman being a detective is what the story is mainly about.
In the first case, the ! tag does act in shorthand to describe the story's main idea, but I agree that the second case is iffy.
It's characterization tags (Warning: TVTropes)
Why do you think that rationality helps a story?
Other way round. The story helps rationality.
I hope for the day when "stupid characters" is seen as being as fatal to a story as "and it was all a dream."
Two main reasons come to mind.
First, HPMoR introduced me to certain new ideas in ways I found pleasant to learn, such as "learning how to lose", and I would like to read more fiction that does similar things - even if I have to write it myself.
Second, if such stories are written well, and do present rationalist ideas in ways readers find pleasant, and, perhaps, they introduce such ideas to new communities (eg, the furry subculture) in ways compatible with those communities' standards, then it might help nudge up the sanity waterline a teeny bit.