^^^
I had a discussion with some peeps about the concept earlier in the year. You can apply it to many facets of life. It's like planting a seed (e.g. proposing marriage, studying a course to get a job, buying the machinery needed to start a new business). The seed can either grow or it can end up not being fertile. Those are two possible outcomes that exist simultaneously until one of them is proved to be a dud.
So in the world of opportunities, while this is a major oversimplification, the concept can be put as "Bust a move. You won't know (if it will work) until you know, and there's only one way to find out."
With regards to the "the observer decides the fate" bit, I don't know so much. One can put in all the efforts they're able to and still end up with a negative outcome.
Anyway Mrs Jones, what sparked your thoughts on this?