Ed Sheeran successfully defended his copyright court case, what is chord progression and why do so many songs use it?

Question

I watched a video where he demonstrated that many songs use the same tune / Chord progression (?). What is chord progression and why was the one in question essentially uncopyrightable?

In: 531

Answer 1

Chord progression is literally pulled out of the air from the vibrations of strings, whether on a piano or a guitar or a uke. The fact the D goes with G goes with Em goes with C is a natural phenomenon. B7 might fit, but not E.