What is the simplest set of rules a masquerade can have to maintain history as we know it?

Question

A common trope in fiction involving things like magic or aliens is the concept of the "Masquerade", wherein the fantastic elements of the setting are kept secret from most of society. While the in-universe reasons for this vary, the main purpose of it as a writing tool is generally to make sure that the world of the setting outside of the fantasy/sci-fi elements most closely resembles real-life, to cut down on complicated alt-history worldbuilding and/or make the setting more relatable to the reader.

However, realistically, that ulterior motive requires a heck of a lot more than just keeping humans from finding out that the fantastic elements exist. If that were the only rule, what's to stop, say, Mircalla Karnstein from using her vampire mind control powers on the political elite to legalize gay marriage in the Victorian era? What's to stop some telepath from posing as a prophet, impressing the humans of ages past with their "divine knowledge", and starting a religion around themselves? What's to stop any particularly powerful member of these groups from gaining influence on human politics and development behind the scenes?

It seems pretty clear that most masquerades, for whatever reason, aren't just about not getting caught. They're implicitly also following something akin to Star Trek's Prime Directive:

As the right of each sentient species to live in accordance with its normal cultural evolution is considered sacred, no Starfleet personnel may interfere with the normal and healthy development of alien life and culture. Such interference includes introducing superior knowledge, strength, or technology to a world whose society is incapable of handling such advantages wisely. Starfleet personnel may not violate this Prime Directive, even to save their lives and/or their ship, unless they are acting to right an earlier violation or an accidental contamination of said culture. This directive takes precedence over any and all other considerations, and carries with it the highest moral obligation.

Except in this case, it's being enforced on people secretly living within a society rather than generally existing outside of it, and also it's not "introducing superior knowledge", it's "shaping human development to more benefit members of the secret society". There's clearly a set of rules in place forbidding this secret society from making human culture substantially different from what it would have looked like if this society didn't exist at all.

But what would that set of rules actually look like? Setting aside the in-universe purpose these rules would serve (as the actual in-universe justification of masquerades is an infamously shaky topic a lot of readers aren't satisfied with), assuming the motivation is there, what would be the best way for said rules to be laid out?

What is the simplest set of rules a secret society can follow in order to prevent their existence from having an influence on human culture and the march of history?

Answer 1

Who's to say there ISN'T influence?

FRAME CHALLENGE: One of the most common tropes in literature (or conspiracy theories) is the idea that people are currently manipulating society to fulfill their own visions of the future. Aliens, vampires, Reptoids (if you consider them separate from aliens) and the like are all portrayed as quietly shifting society, and that they have been for decades, centuries, or even millennia.

It is FAR from clear that a masquerade requires a prime directive. In fact, I would argue that a masquerade would REQUIRE interference in society so evidence disappears, un-cooperative public figures disappear without leaving evidence, or people are given plausible reasons WHY that video showing vampires feeding is an internet hoax. The media would be influenced, leaders influenced, and possibly (like in Men In Black) large portions of the populous directly influenced.

So maybe L Ron Hubbard was a telepath and DID start a cult revealing truth, and had to be silenced because of it. Harvey Weinstein? Totally a tool of the Reptoids. The FBI? Most of their budget is spent doctoring evidence to make vampire attacks "disappear."

Besides a rule to maintain the masquerade, you'd probably need a rule requiring the creation and maintenance of a giant conspiratorial organization charged with maintaining the masquerade (let's call it "the Illuminati"). The aliens, vampires, Reptoids, and Scientologists would all need to sit down at a table and hash out who controlled what, how disputes would get handled without public exposure, and what the powers of the conspiracy would be.

In fact, if you DID have multiple supernatural factions to contend with, the only thing likely to STOP a global supernatural war would be an agreement to maintain a public façade or normalcy.

Answer 2

God Did It

As with so many things, God solves your (narrative) problems. You don't need a lot of rules to maintain a Masquerade; you don't even need your Masqueraders to be quite sure of the exact rules. You just need them to be profoundly and universally terrified of breaking the Masquerade.

Can one or two vampires living quietly on the edges of society get along, but lightning reliably strikes any vampires which wreak too much havoc, or who try to actively set up a cult to themselves to religiously/politically dominate a kingdom? (Even if they never go outside!)

Are the people of Faery left alone in their underground kingdoms, and allowed an occasional midnight procession beneath a moonless sky, but they know (they know) that they are not "permitted" to set up an above-ground kingdom, or to openly negotiate with or threaten the mortals? (Whatever woes they are allowed to inflict on mortals unwise enough to wander into their territory...)

Is the occasional wizard allowed to sell his soul to dark powers (or not-so-dark?)... But even those dark powers will withdraw and leave our wizard powerless if the wizard presumes to make a too-public show of his dearly-purchased abilities? (Because the dark powers themselves get punished if they overstep, even if they do it through a proxy.)

If there's a big, ageless Something which effortlessly and ruthlessly eliminates any Masquerader who makes too much noise, the only rule required to maintain the Masquerade is the simplest and most straightforward rule of all: Self-Preservation

Answer 3

The Truman Show

Puppeteers who run the Masquerade (TV Tropes warning) are doing it, first and foremost, for the show. And some of the basic rules of showrunning is to avoid goofs and breaking of the fourth wall (unless this is showrunners' intention, and in our case it is apparently not).

So the secret society that stands behind the "real" world tries its best to stay hidden. If some "unmasking" is happening, they try their best to cover it up.

One simple rule that guides them is "The Show Must Go On".