Earlier quoted context omitted.
So the reason I brought up physical property is because if that's not a complete fiction then it's bizarre for intellectual property to be a complete fiction. Governments don't create things out of whole cloth, the laws always correspond to something, even if they do it badly.
"the reason I brought up physical property is because if that's not a complete fiction then it's bizarre for intellectual property to be a complete fiction" I am not following your logic here. The notion of physical property predates written records and codes of law, even if it has been approached differently by different cultures. The notion of intellectual property is a far more recent development that has nowhere…
Trademarks protect brands and go back a very long way; primitives would use them to distinguish themselves from each other, farmers would mark sheep, etc.
Patents are really protections on inventions. Inventions also go back a long way, although they were previously treated as trade secrets rather than open descriptions. Reverse engineering and a desire for openness instead of secrecy created the need for patents (I'm not saying the governments are doing a good job.) A chef's secret sauce is his intellectual property.
The idea of copyright stems from a desire to protect the older concept of authorship and goes back to antiquity as well; drawings in caves were certainly made by cavemen; the Greek philosophers certainly originated their words; narration in the bible is attributed to certain authors (although there is sometimes dispute here); Mozart (barely) survived on the patronage of his compositions.
That's all I mean by it's not a complete fiction: it's a set of protections around things that we already valued but that were started to get degraded by modern society.