[krisoft]

> With due respect, what we need is actual research based on actual evidence

I recommend “Tinkuqchaka: A Suspension Bridge over the Upper Pampas River, Ayacucho, Peru” from Lidio M. Valdez, and Cirilo Vivanco. Published in the Journal of Anthropological Research, 2021.

It has its limitations of course. It describes present day rope bridge building practices and there is no guarantee that those practices are the same as in days of old. But given that the bridges themselves rot away and the ancients are not around to interview this is likely the best description you will ever get.

[mmooss]

Thank you. I am not wondering how to build rope bridges; lots of cultures figure out some interesting local technologies.

It's the Inca's scale that is what sets them apart - doing these things, at a very high level and with great success, over enormous distances and populations.

A few civilizations achieve these things, the great majority don't; what is the difference?

It is a common question asked by scholars for generations about all sorts of places - for example, see the popular book Guns, Germs, and Steel by Jared Diamond.

[krisoft]

> I am not wondering how to build rope bridges

You were just a few comments ago. You were specifically asking how bridge construction and maintenance is communicated over great distances and time. Let me quote your very own words to you: “how do you communicate, for example, rope bridge construction and maintenance information over great distances and time”

This is the only thing i have answered because your wider “how do the inca do?” question is not specific enough to be answerable.

And the answer to that specific question is that no maintenance information needs to be transmitted and the construction information is spread as folk tradition. Bridges are usefull enough that local villages want them to be built, and they are perfectly manageable as a local effort. And then the next village sees that a bridge was built, they also want one and find someone who knows how to build one and they do. You repeat that a bunch of times and you have a bunch of rope bridges all around. There is no mystery there.

This idea was so alien and unbelievable to you that you accused me of promulgating some sort of conspiracy of playing down the importance of literacy. Not cool.