I own a fascinating collection of treatises on plagiarism in the volume Perspectives on Plagiarism and Intellectual Property in a Postmodern World published by State University of New York Press. Beginning on page xv, the Introduction makes the point:
“Plagiarism is perceived as a problem but it is often discussed in simplistic terms: "using someone else's words without telling whose they are or where you got them"; "stealing other people's ideas or words." This basic view of plagiarism comes directly from the Latin source of the word, which meant to kidnap a person, referring only to children or servants or slaves: people who could in some sense be owned...
A postmodern perspective of plagiarism and intellectual property suggests that one cannot own ideas or words. All we can do is honor and recompense the encoding of those ideas...”
I note (with considerable interest) that these editors, themselves, did not hesitate to simply enclose particularly apt phrases in quotes and move on.
Who owns the river as it flows past our fence? Do we hesitate to dip out what we need for our cooking pot or hesitate to piss back into the stream? Who owns the flow of ideas that constantly swirl and eddy through our literature and its many tributary media branches?
We cannot always know where our sources come from nor distinguish the edges with precision. Still, honor is due. I have a fading memory of accompanying David Winston, a Cherokee herbalist, on an “herb walk.” As he crossed a small stream, he bent down, raised a few drops and touched them to his lips. He explained that the point of the act was to maintain an attitude of honor and appreciation for our resources.
My point is that some nuance applies to the subject. Most things cannot be accurately reduced to absolute binary alternatives. Still, I have respect for your fence; I will pay money for your bottled water, and I will not put your brand on the labels of my bottled water.
However, the movement of ideas cannot be constrained as if reducible to stone walls, heavy gates and monuments. The wind must, by its nature, blow through any crack. Rain will fall indiscriminately on any field. The resulting mass of water must find its way under, around or over any obstacle. Ideas must propagate like swirling wisps of dandelions, dancing on the breath of God, seeking new life in new places.