Cultural rise and fall is commonplace. “Barbarians” often defeat “advanced” cultures and eschew the learning of the defeated until (much later) they realize there was value to it… as they transition from

being the barbarians to the advanced culture waiting to be defeated.

a possible solution to the argument, but when faced with a large scale it is difficult to conceive, the entirety of Europe saw the sudden and unexpected collapse of rome.

that wasn't to doing with barbarian take over and yet the world forgot how to make underfloor heating or aquaducts etc etc

the vast amount of knowledge brought towards Europe from a highly sophisticated china was vast, and yet that too was stilted until much late, perhaps this time by the Mongols but still

Well, consider the Library of Alexandria—it outlasted to Fall of Rome and clearly contained vast amounts of knowledge, until it was eradicated by barbaric Christians.

“The Fall of Rome” was really a long, protracted event, too; the Western Empire was in decline for quite a long time as outsiders pressed in and internal problems weakened the society,

leading to the eventual sacking of the city by “barbarians.”

Throw in that the socio-economic leaders post-Empire were suspicious and hostile to “pagan knowledge,” and I think that explains at least some of the loss of advanced knowledge that spread

through Europe in the post-Roman period.

Consider, as well, that advanced knowledge is expensive: it takes a lot of effort to construct and maintain an advanced civilization. When the social and economic support structures vanish, the ability to

afford, e.g., subfloor heating when you are struggling to raise food to support your family vanishes.

very astute reasoning and probably answers my question, add that on to the expense, value and difficulty of creating the written word I can see why it isn't well documented. but i would go further than this,

i think it is human nature to learn and be curious, at some point in that history entire civilisations stopped learning, the only thing i think can cause that is suspicion and religion

but if we are saying Christianity destroyed vast amounts of knowledge then at least it was thanks to Christianity that the knowledge was restored to Europe.

interesting diagram

we may be moving from abundance to complacency, but i don't think we could be

economically yes governments spend less and less on development but invention now turns to crowdfunding and sees new life, with that as a basis invention need never decline

we have also neglected the other part of my question, which i will simplify, why do we see pyramid structures in Egyptian land and mayan land. how did this concept spontaneously arise so far apart

i could find other examples of where the same concepts arise in different locations that seemingly have no access to each other.

this is true but if we look at the spread of dna across the world you see where humans colonised from and to, one group came from Africa through the middle east towards china and the other towards europe

so native americans in dna resemble Chinese more than African dnas so i don't think Egyptians and native Americans have that closer an ancestor

Sometimes the answer is “just because.” The peoples of Central America and Egypt need not have ever had any contact for similar structures to be created.

Perhaps someday we’ll discover such a link, though I think it unlikely due to the impermanence of pre-stone cultures.

perhaps

there is of course older step pyramid platform type structures through Mesopotamia which could make rise to Egyptian structures, anyway its another thing that i am not satisfied with

Don’t forget the other pyramidal structure builders to the south of Egypt. Also, there are massive structures as parts of other cultures that had easy access to stone or similarly strong building material.

We don’t know if there were similar efforts in non-stone cultures that did not survive to pass on the information, sadly.

true