Answered a medical question for one of the kids and thought about how I'd learned that sort of thing, and realized a lot of it came about from the Internet. With the proliferation of slop these days, I feel like that window of (semi-)reliability was briefer than we would have expected.

Don't know how that's going to play out for real-world Terrans, but in my universe there was a full informational collapse: maybe you can't erase history, but you can sure make it a needle in a haystack. Terran history is basically unknown prior to (and to a certain extent, even after) starflight, because there are so many Alternate Facts.

To this day, Terrans (of all flavors, some more than others) are what other societies consider "conspiracy-minded" -- there is very little trust in authority or facts that can't be personally verified. "Do your own research" is very prone to confirming priors, so a lot of Terrans live in their own realities. How does anything get done, then?

Science cults.

The non-core regions are less like this, but in the Terran core, science and technology is advanced only by people who have established a set of facts and believe them. Outsiders just consider them "normal people" but they are portrayed as mad scientists in Terran media, and getting a new advancement accepted by the masses requires a PR blitz that is effectively "while trying to destroy civilization, they accidentally came up with a product we all need!" -- while competitors are trying to portray it as dangerous and subversive, right up until they catch up technologically.

Science cults are deemed dangerous in part because they talk to, and share a reality with, non-Terrans. The necessity of this is quietly recognized -- for example, Terran students go to Apa Kudi because they need to keep up on drive technology, even though one in five students defects to the Union. (The number would be higher, but Terrans try to only allow students whose family reputation would be ruined if they defected to go in the first place.) The risk is recognized as well; science cultists are rarely permitted into positions of power.

It's not a full Idiocracy setup, though fascism tends toward that by nature. A leader has to be as sincere about sharing the reality of their followers as possible, since hypocrisy is permitted but never insincerity. That is, a leader has to fully believe that Zhdez anti-aging treatments are a cover for mind control, while simultaneously making use of them "as a sacrifice" because their leadership is so important. A 150-year-old planetary governor passing laws prohibiting travel outside the Republic past age 100 is simply accepted, even if it comes out that the law was signed while he was in a clinic in the Zhdezplier.

Science cults are mostly hereditary, for a couple of reasons: scientist parents tend to pass on education and their presumably reality-based views to their children, and the children of scientists are regarded with enough suspicion that generally only scientists will hire them.

(Annnnnnd as I realize that I'm using "scientist" to refer to these people, "scientism" is the logical -ism for outsiders to accuse them of, and I'm semi-delighted to find out the term exists and is exactly what I want. It also describes the fallacy that science cults are prone to:

an exaggerated trust in the efficacy of the methods of natural science applied to all areas of investigation (as in philosophy, the social sciences, and the humanities)