Heisenberg’s principle implies that the observer (a human?) can affect an outcome merely by the act of determining that outcome. Scientists among the readers may raise the objection that the principle applies significantly only to very, very small objects and that I’ve omitted momentum, etc., but just suppose . . . .
A little birdie flies through an uninhabited meadow each day and does what little birdies sometimes do. With no one to observe, its excrement may be spread as a probability function thinly over the entire meadow. But one day a human walks into the meadow and observes the bird’s flight. Heisenberg’s principle says that the act of observation means that the excrement must fall to an exact location. And that’s why birds always poop right into the observer’s eye.