I gave up long ago on formulating what seems like a new concept as I came to peace with the fact that billions of people alive and dead means there's very little room for new concepts. (just an anecdote, not the focus of my question)
So I want to know what theory or concept describes the idea in which constantly comparing two things (or more?) in a "yin and yang" like opposition would associate rivalry between the two things even if non existed before the intentional creation of this comparison.
This idea came to me through observation of how politics and media works, whether scientifically intended or just mere learned through experience, in instigating seemingly unrelated concepts in a comparison situation, and enforcing that comparison on the masses to create such rivalry between the two concepts; then have the ability to influence external factors to skew the mass opinion one way or the other. It works because they're using it then with the oldest trick in the books: divide and conquer. So they get those two things, put them in such a rivalry comparison where if one existed the other can not exist at the same time, creating division and "teams" of sort, then appealing to each team in some way or the other to win its loyalty.
So the question is:
What theory or concept describes the creation of rivalry between two ideas to instigate division?
One idea I had was really just describing it as "competition". But this doesn't work; In competition, there's variable degrees of existence of each competing idea. However in the case of my question, where one idea exists in some context, the other idea can't.