I've just remembered that a while ago, in another thread, Argos posted a link to an article that described Popper's argument about the Uncertainty Principle and an experiment based on it. But the authors argued, on theoretical grounds, that test was not conclusive. I think it was the same test he describes in this link. Here's a copy of the article (pdf), and here's the Wikipedia page.

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"All your bias are belong to us." Ara Pacis
"A witty saying proves nothing." Voltaire