Wheeler suggested to expand the observations of the "double slit apparatus" into the "delayed choice experiment" which was then itself expanded into the "delayed choice quantum eraser experiment." From the Wikipedia article:

"Wheeler pointed out that when these assumptions are applied to a device of interstellar dimensions, a last-minute decision made on Earth on how to observe a photon could alter a situation established millions or even billions of years earlier."

https://en.wikipedia.org/wiki/Delayed-choice_quantum_eraser

That's not to say that this is "proof" but I think this is where the notion is most directly apprehended.