You know how the history of science is littered with cases where progress was held back because so many people couldn't let go of their preconceived notions? It's why rationalists prize the ability to abandon preconceived notions, and to do so quickly, regardless of how many people stand by the notion currently. "Speak the truth though your lips may tremble" and all that.

Seen through that lens, women's role in history can be another case study of mass-delusion. Lots of people were unable to see the fact in front of their noses: that women are people. Even the women themselves didn't see it. Yet it should be the simplest thing in the world. Isn't that worrying?

If our brains can serve us that badly, how do you know yours isn't keeping up other massive blind spots?

The concepts of intersectional feminism are not just things you learn in order to be able to claim you did your part in building a more equal society.

They also give you some practice at deconstructing deeply entrenched Aliefs. Even today, nobody is free of aliefs around gender… it's a collective project to catalogue them all, hence that gender studies is a field of research.

We can benefit from what they have found so far, like premade lessons. But the biggest leg of the journey is within yourself, as you digest this material. You get to observe, almost directly, the shift that happens as various hidden attics in your mind get unhidden, and you realize they were there all along, and it's humbling that, you know, you just didn't see them.

Best of all, you get the kind of personal development that makes you feel like a more complete human being.

We speak of "hearing" our internal voices, and scientists have seen activity in the brain's auditory cortex when we do. Apparently we've also been able to reconstruct images from a cat's visual cortex, seeing what it sees.

One day, we'll likely be able to read back someone's internal monologue.

That's useful to know in the p-zombie thought experiment, which tries to eliminate dualism without eliminating it. It's the idea that you could have a world where all the people behave exactly like people in our world, but nobody is home in their heads to experience things – no "soul" so to speak. Philosophical zombies. Pretty much what René Descartes (1596–1650) thought of non-human animals, but extended to claim that the very fact that people go around talking about feelings still isn't proof that they experience any.

But in this purely "mechanical" world where nobody's actually experiencing anything—where there's nobody we would think of as alive—why would the p-zombie have an internal voice, and talk to other p-zombies about how they experience their internal voice?

Dissolving the thought experiment gets very deep, so I'm stopping here.

(Paraphrasing www.greaterwrong.com/posts/LaM5aTcXvXzwQSC2Q/universal-fire)

At the time:

• There was no cell theory of biology
• Nobody knew about DNA
• Nobody knew about thermodynamics, that "matter can't be created or destroyed". If you focus the Sun on a goop of antimony, it'd billow a thick white smoke for a while, and then weigh 10% more than before, and people thought why not? They saw no reason the sun couldn't add weight to some things.

It was a time when you'd look at your hands, flex them, and have absolutely no idea what moves them, why they move, while clay molded into the shape of hands just sits there.

Lavoisier discovered fire, i.e. combustion, and that we organisms also do some form of combustion, because like a fire, we consume "vital air" (oxygen) and replace some of it with "fixed air" (carbon dioxide), and the more so when we do physically demanding work. Here was why we need oxygen just as badly as a fire does: we operate by the same process! Amazing!

He discovered that if you weigh not only the thing being burned but also the gases in the room, the total weight of both stays the same before and after a fire. Burning wood releases the wood's matter into the air, while burning antimony sucks some matter out of the air, hence why the burnt antimony weighs more.