Ok, this is where the misunderstanding exists. Here is what I actually assert:
There is no Classical Vacuum in which you can observe only virtual particles.
Do you disagree with that?
Sure there is. It's called a quantum vacuum.
Of course, when I mentioned that, you said "But the quantum vacuum isn't a classic vacuum". And then I said "No, a quantum vacuum is what you get
instead of a classic vacuum, because of
virtual particles".
And then we went in circles
some more.
And then I pointed out that I didn't even
need to show you either, that Heisenburg Uncertainty in general, and the Casimir effect in particular, are perfectly strong enough evidence on their own. You wouldn't get the Casimir effect if the quantum vacuum didn't work exactly as described.
But you don't want to accept that, because you don't want to admit your error. So you keep
ignoring it, and keep repeating your errors. And thus leading to inanities like "Show me a pure vacuum!". To which I respond "Show me the interior of a star, before I can accept nuclear fusion".
Insisting on such ludicrous "proofs" for quantum mechanics, while ignoring the far more powerful and predictive evidence is to bury your head in the sand.