I'd say that reality exists because people have a desire to perceive the world around them. I.e. if people didn't care, never opened their eyes, reality wouldn't exist to them. Sometimes they would randomly get hit by a bus, but they would ignore that.

Reality only exists because people have a conscious mind that makes them perceive reality. As such, that necessitates that reality is guided by some principles, because even if reality had no principles, that in itself would be a principle. So, the exact way that electromagnetism works is only a detail, but that there are forces to begin with is solely dependent on your conscious choice to even look at the world around you.