The reason is that opinions cannot really be proved true or false.

There was a good chance that most, or all, of them would prove false.

But he proved false, and she never saw either mother or money.

He was not going to claim any talent which could later be proven false.

All the gods I knew had proved false to me.

However, this is proved false with the revelation of the town's true history.

If ever I prove false to her, to the girl that loves me.

The hypothesis will be proven true or false and nothing in between.

I do not deal kindly with those who prove false to me.

"All have proven false, and I'm certain this one will be as well."