memes

As Bohm argued, autonomous objects are human inventions.

Yeah but they are not just arbitrary inventions. They are necessary inventions which every type of animal or intelligent being would necessarily make, and that puts them on a higher ontological level.

This is where your Plato point breaks down. You replace the ill-defined river with another definition including an ill-defined “shape of the landscape,” which is also changing all the time just as much as the river does, with no singular and consistent “shape of the landscape,” and its very precise shape is impossible to rigorously define even at a single time instant.

Well, i get your point, but what plato does is actually to go further and not just replace the water with some curve in space, but he goes on to say that precisely because the shape is infinitely complex (and we can therefore not comprehend it anyways), we have to replace it with something simpler in our mind. something like doing the following:

replace the fuzzy nature of reality with something simpler, which then (by agreeing upon it), becomes what we call real.

funnily enough, that's exactly the argument that you seem to be making. "reality" is perceived by us precisely because it is a social construct that is useful to us, and therefore it has to be simple.

For example, Benoist would say that, if you are talking about a river in the abstract, it does not refer to anything real. But the word “river” serves as a socially constructed norm that can be used to judge reality to be something, and thus can be employed in a social setting. If I see a river and point to it, and say, “look at that river over there,” the river is now not just an abstract symbol, but it is a symbol pointing to something in a real world context, where people can really observe its glistening surface, dip their toes in it and feel its cold water, etc.

Yes, precisely, that is why we think abstract thoughts. Because they convey information more meaningfully than the thing with you call reality. Check out how pictograms are used by IKEA furniture, chemical lab danger warnings, anime etc to convey information, because that is actually clearer / more fun / easier to digest than to use real-world depictions. Thus, by social contract, these abstractions become our reality, just like the smartphone has replaced actual inter-human contact.