Back in college, I had a summer job as an assistant coach at a public school summer program. Humanity's powers of self-delusion never ceased to amaze me. I would see with my own two eyes that a runner was safe. I'd make the call. "Safe." (The runner's team would agree with me -- but that didn't count, because he was on their team.) The opposing team would swear by all that was holy that the runner was out. They'd be outraged at me, sputtering, wild with righteous anger. Clearly, I hated their team. I wanted to see them fail. This wasn't an act. They weren't simply lying. They knew the runner was out. (Of course, I knew the runner was safe. I'd seen it.) They had re-framed their memory, re-edited the tape.
Obviously, this is why professional sports rely on cameras, instant replay, yattayatta. But when all you have to go on is human perception and memory, the definition of "truth" becomes a contest of wills.
Being disinterested and objective is the referee's job. The opposing teams want to win. Each team fights for the version of reality in which they win. Each team is doing its best to shove this "truth" down the referee's throat. It's a dilemma, folks. Ironclad. Inescapable.
To see the world clearly, you can't take sides. To change the world, you have to take sides.