[joesmo]

If privacy is a distinctly modern idea invented in the 1890's what was the purpose of window curtains before then? Certainly they couldn't have been there to protect an idea that's probably older than language and likely has actual biological basis. I assume also that humans only started to have sex in private in the 1890s according to your theory as it wouldn't have been even possible to conceive of privacy before the idea of privacy existed?

The idea that privacy is something new is absolutely absurd and laughable.

[ddebernardy]

Consider reading the post I linked to. And let's not forget Window taxes from the 19th century:

https://en.wikipedia.org/wiki/Window_tax

In earlier ages, there were few windows owing to architectural and building technique related constraints. If anything the window taxes reeked of "oh shoot, these guys are rich and can afford modern construction techniques." Your home with plenty of light flowing in is in fact quite modern.

[SixSigma]

> what was the purpose of window curtains before then?

Draught exclusion and insulation from convection.