The idea of copyright seems like a pretty simple idea.
If it was your idea then you own it.
But where does this start and where does it end?
I imagine even in the earliest days of our existence we'd have claimed ownership over a stick we found. That the simple act of sharpening the stick would be something that would make it “your” stick and that someone else sharpening their stick like ''yours'' is ripping you off. Today when we decide that C, G, Am, F is a good chord progression we make the same claim. The difference can be summed up in one word. ART. Once we create something we widely believe that it is our intellectual property. There are so many shades of grey regarding what we own when it comes to art.
Many artists have signed contracts that hand all the publishing rights to the company, putting the artist in mass amounts of debt while company executives get rich off their art. This same old story has happened to so many big name musicians The Rolling Stones, Bob Dylan, David Bowie, Tom Petty (to name a few) have been ripped off and left completely in debt and have come back on top by learning more about the business and developing contracts that suit their needs better.
A lot of classic music has been sampled and twisted into a new sound combining stealing someone else's idea with creating your own. And now companies have started to run online campaigns. “share this post... with what you think about... to win” so they can use your intellectual property to sell your idea back to you.
So what is it that gives you ownership of your intellectual property. The simple answer is your contract. If you haven't got a copyright you don't own it and if your contract says that the company owns it. Then you do not have a leg to stand on. Unfortunately, copyright has nothing to do with philosophy and everything to do with the law.