Hmm, maybe we should use the infamous half-your-age-plus-seven "creepiness law"?
What's that? O.o
In this specific case, I think the socially-constructed adult/child divide might actually work - sure, it's arbitrary, but it should largely reflect whether the kid in questions views someone as An Adult or just another kid.
I think in most circumstances that would be relevant, social roles largely outweigh and override this. In most cases, minors are forced into roles by circumstance and because people who already have greater power force them to be in such roles.
For a better intuition pump towards what I mean, think of The Internets, particularly hacker culture. There, age is probably the most irrelevant out of any culture I've seen - only maturity, skill, and some online social likeability matter. Some mature 12-year-olds wield immense power (relatively speaking, in terms of social and cultural power within the limited scope of hacker culture) over some of their peers, and this almost certainly leads many major adults to take suboptimal decisions or actions within the context.
Sometimes, gamers can also form similar small groups where young people with the proper, more powerful "role" can wield relatively disproportionate power over the leisure time and entertainment quality of their peers. I've sometimes experienced this firsthand, though the worst cases I saw didn't happen to me personally.
For a toy example of what I'm talking about, consider gaming "clans", groups of people who for some reason or another end up gaming with eachother and forming a common In-Group mentality and generally acting like a tribe for the purposes of playing videogames (or some small set of games). Often, some gamers will get really invested in this tribe, emotionally and psychologically, and will make friends there, and spend lots of time making emotional attachments, and so on. More often than not, these groups have a "Leader", who holds rather disproportionate authority, much like a tribe. In fact, these usually work pretty much exactly like a tribe.
Anyway, this emotional involvement can mean that that kid who would be considered a minor and unable to consent due to power imbalances actually has more power over you now, because failure to comply can, in typical tribal fashion, get you kicked out - which, while not as bad as getting kicked out in the ancestral tribe, in many cases will still sound pretty shitty, and may deprive people of otherwise-reliable good entertainment, and generally just lowers the quality of their leisure time quite a bit depending on how much they enjoy the game and the community they play with.
And then all the meta and game-theoretic concerns apply: if I'm wary that failure to comply might get me kicked from the tribe, I may try to implement the same kind of social status strategies we see in other tribelike contexts. This includes anticipating possible things that the tribe leader might care about and conforming pre-emptively, which would mean I'm taking an action that is sub-optimal or that I don't want to do, based on my anticipation of possible failure-to-comply situations, without any form of intentional coercion from the group leader.
All of this leads up to: Situations like what I just said, where no actual coercion happens but where someone is accepting some action or situation or thinking in some way that they would prefer not to, generally build up gradually. I would not be surprised if this could easily lead a person into thinking in this manner about sexual interaction (given a social culture that has less taboos against sexuality), and make them build this up into eventually accepting or even offering to have sex with someone solely because they anticipate that them not making this offer could lead to eventual bad consequences for them due to the power imbalance, or something.
This all reminds me of situations where, for example, A wants to blackmail B, but C watches closely for any explicit form of blackmail, so instead A will create a favorable situation by removing all of B's options and power, and then present themselves as willing to help, in a manner where B contextually knows that A is in a position to mess up their life if they don't offer, say, sex.
From the outside, it will either look as if B just fell prey to A's superior prowess, which is normal in many domains such as competitive businesses, or A and B suddenly formed a partnership due to friendly human interactions that were apparently fully voluntary on the part of B (since B initiated it, after all).
So merely the perception that offering sex to A is the only way for B to stay afloat¹ creates a subtle blackmail-like situation that in many cases no one could form a legitimate legal case around in most instances. Many variants of this exist or could happen in various situations.
What's that? O.o
As the name I referred to it by suggests, you divide your age by two and add seven; anyone below that would be "creepy" to sleep with or otherwise engage romantically. Not sure where it comes from, but it's been featured in XKCD at least once.
[snip social-pressure rape description]
Yup. And in our society, all kids are in these situations, and many (especially younger) kids may assume such a context in pretty much all interactions with adults. Not to mention the fact that, currently, most people who actually do have sex with children are in such a position of "soft power" over the child.
LessWrong has been having fun lately with posts about sexism, racism, and academic openness. And here just like everywhere else, somebody inevitably claims taboo status for any number of entirely obvious truths, e.g. "top level mathematicians and physicists are almost invariably male," "black people have lower IQ scores than white people," and "black people are statistically more criminal than whites." In my experience, these are not actually taboo, and I think my experience is generalizable. I'll illustrate.
You're at a bar and you meet a fellow named Bill. Bill's a nice guy, but somehow the conversation strayed Hitler-game style to World War II. Bill thinks the war was avoidable. Bill thinks the Holocaust would not have happened were it not for the war, and that some of the Holocaust was a reaction to actual Jewish subterfuge and abuse. Bill thinks that the Holocaust was not an essential, early plan of the Nazis, because it only happened after the war began. Bill thinks that the number of casualties has been overestimated. Bill claims that Allied abuses, e.g. the bombing of Dresden, have been glossed over and ignored, while fantastic lies about Jews being systematically turned into soap have propagated. Bill thinks that the Holocaust has become a sort of national religion, abused by self-interested Jews and defenders of Zionist foreign policy, and that the freedom of those who doubt it is under serious attack. Bill starts listing other things he's not allowed to say. Bill doesn't think that the end of slavery was all that good for "the blacks," and that the negatives of busing and forced integration have often outweighed the positives. Bill has personally been the victim of black-on-white crimes and racism. Bill is a hereditarian. Bill doesn't think that dropping an n-bomb should ruin a public career.
Here's the problem: everything Bill has said is either true, a matter of serious debate, or otherwise a matter of high likelihood and reasonableness. Yet you feel nervous. Perhaps you're upset. That's the power of taboo, right? Society is punishing truth-telling! First they came for the realists... Rationalists, to arms!
Or.
We can recognize that statements like these correlate with certain false beliefs and nasty sentiments of the sort that actually are taboo. It's just like when somebody says, "well science doesn't know everything." To this, I think, "duh, and you're probably a creationist or medical quack or something similarly credible." Or when somebody says, "the government lies to us." To this, I think, "obviously, and you're likely a Truther or something." Bill is probably an anti-Semite, but Bill doesn't just say, "I'm an anti-Semite," because that really is taboo. He might even believe that he shouldn't be considered something awful like an anti-Semite. Bill probably doesn't think Bill so unpleasant.
That's the paradox: "taboo" statements like black crime statistics are to some extent "taboo" for sound, rationalist reasons. But "taboo" is not taboo: it's about context. People who think that such statements are taboo are probably bad at communicating, and people often think they're racists and misogynists because they probably are on good rationalist grounds. If you want to talk about statistical representatives on the topic of race, be ready to understand that those who are listening will have background knowledge about the other views you might hold.
All this is the leadup to my question: what highly probable or effectively certain truths are genuinely taboo? I'm trying to avoid answers like "there are fewer women in mathematics" or "the size of my penis," since these are context sensitive, but not really taboo within a reasonable range of circumstances. I'm also not particularly interested in value commitments or ideologies. Yes, employers will punish labor organizers and radical political views can get you filtered. But these aren't clear matters of fact. I also don't mean sensitive topics like abortion or religion, nor do I mean "taboo within a political party."
Is there really anything true that we simply cannot say? I have the US in mind especially, but I'm interested in other countries as well. I'm sure there are things that deserve the label, but I've found that the most frequently given examples don't hold water. I think hereditarianism is a close contender, but it's not an "obvious truth." Rather, my understanding is that it is a serious position. It's also only contextually taboo. If it were a definitive finding, it could perhaps become taboo, though I think it more likely that it would be somewhat reluctantly accepted.
Any suggestions? If we find some really serious examples, we might figure out a way to talk about them.