"I don't know the metaphysics of this! Something that was definitely added since last year probably won't affect whether, I don't know, one of the teachers had a baby or not, but anything from longer ago will almost certainly affect somebody's baby at least to the level of which sperm. Agreed about editing each other's."

"You have a point..." Edie flips through the handbook looking for obviously-recent things. "We could try the print quality thing again, since any damage that caused is likely already done? Maybe I should poll people about babies since I'm known to do weird things involving talking to a lot of people--no, changes on the level of which sperm wouldn't necessarily be evident in a small child even if we knew what to look for, which we don't." 

"I'm not a hundred percent that I remember my exact wording but I'm pretty sure it was at least very close to what I wrote down separately, 'and commitment to print quality' at the end of Our Values. Do you want to try it in mine or vice-versa first?"

"You already have mine, you go ahead."

Bella preregisters her experiment, and then writes "and commitment to print quality" in Edie's handbook with more trepidation than anyone has ever written those words before.

"Well, I don't remember any yearbook reprints," she says after a moment. 

"Okay." She preregisters the other experiment and hands over her misprinted handbook.

She adds the print quality value, closes the book, and frowns. 

"I remember both the yearbook reprint and the yearbook not reprint. --Uh. I am not sure changing only recent stuff is going to avoid having the effects we want to avoid."

"I don't remember the yearbook reprint, so I guess that means I and the handbook are special. - why do you think so."

"Because it isn't just the school that changed, I remember learning about a Supreme Court case where somebody got killed in an accident and his family blamed a typo in the instruction manual and brought charges against the guys who printed it."

"Jesus! Did we just kill a guy? And unkill him and then return to kill again? - has this affected your memories of homeroom at all."

"Yeah, I remember being perplexed by the cover of your handbook. I'm gonna google the court case while the timeline is still this way and then we can put it back and I can google him again."

"Yeah do that good idea." Are her experimental preregistrations unchanged.

Her experimental predictions now predict changes from a baseline of the new timeline. 

"- shit, it can change my notes."

"That is both not ideal and not surprising. If it couldn't change your notes that would have implications."

"Yeah but it means I have to rely on my own personal brain - or yours and mine together, if you do the changes, which I guess implies you should -"

"I promise I won't go on a mad social justice rampage or otherwise make any changes without your approval. It would be nice if we could do small-scale controlled trials with this that only affected consenting participants but even if everyone in the school was willing to consent we don't really have a way of convincing them to tell us so."

"And it's not just the school, it is sometimes the Supreme Court."

"There are probably changes that could be made to the school that wouldn't need a Supreme Court ruling to justify, like, we ask a teacher something that's in the handbook that could've gone either way and we make it be the other way."

"I guess.

"...I'd be tempted to go public with it to get buy-in for experiments, but -

"- there's basically no way that ends well -"

"Yeah. I mean, if of non-you only the person who writes in it remembers what happened, it seems really hard to, like, scale people believing us. The most likely way would be to convince someone in a position of authority, and...yeah. Plus like. All the other reasons it doesn't end well."

"It's sort of plausible I should take out a safe deposit box and lock it in there and meanwhile spend a lot of time thinking about what to do, but it seems plausible it'll only work this year, or something -"

"It's entirely possible. If only there were a handbook for dealing with this handbook--I wonder if we could extend the period of time it works in, if that's the case, by rewriting how long a school year lasts--or just editing the date--I want to try editing the year on the handbook but I feel like that has, uh, failure modes."

"Yeah. It hasn't determined anything to be a misprint or a prank by the typesetter, yet. If I put the principal's name typo back maybe her name will in fact become Katheriine."