Who Do Ideas Belong To?

"Maria was adrift in a set of conventions she didn't fully understand; she offended without knowing why. Virtually all the writing academics do is built on the writing of others. Every argument proceeds from the texts of others. Maria was only partially initiated to how this works: She was still unsure as to how to weave quotations in with her own prose, how to mark the difference, how to cite whom she used, how to strike the proper balance between her writing and someone else's - how, in short, to position herself in an academic discussion" (Rose, pg. 180).

The above quote is from Lives on the Boundary by Mike Rose and the emphasis is mine. I have wondered for a while now about the point this quotation is making. If academic writing is built on the writing of others, then what makes an academic paper belong to a writer? For example, if a writer publishes an academic paper, which is really just built off of 20 other research papers with a couple connecting thoughts and ideas thrown in, then where is the line between the paper he writes being his and it belonging to the 20 other writers he builds off of. 

If all writing belongs to others, then it's not really plagiarizing to copy text. After all, the writer your "stealing" from has just taken ideas from others to begin with. Even new ideas or thoughts written in a research paper  are rarely a writer's own. The ideas come from conversations, movies, books and the culture a writer is surrounded by. New ideas do not exist in a vacuum. Being the first person to write them down on paper  doesn't mean they belong to you. 

It's kind of like the current race to patent the human genome. Companies are scurrying to patent genes left and right they have no rightful ownership over. Genes belong to everyone. Companies are not inventing these them, they are simply finding them and filling out a patent slip, ensuring others don't have to access to study or use them. If anything on earth is truly a common resource, it's our genes.

Writing is much the same way. Ideas or memes belong to everyone, to copyright some particular ideas or say they are yours is quite bold and any writer that does so is either lying to himself or the public. Either way, the writer is a liar and all we can hope for is he simply doesn't intend it. Hopefully, he is lying out of ignorance, rather than intentionally misleading the public.