I find it puzzling that some claim to have demonstrated something dozens, hundreds or thousands of times, yet not one shred of evidence exists to support that claim.OK. I wasn't specific enough. I was thinking of a threat caused by science doing something wrong or losing its way. You've been arguing against science implying that its foundation is rocky, and you mentioned experiments revealing this. Now you're discussing public policy, governments, industry, etc.. Yes, they are creating problems with the fruits of science, the next looking like it will be what these people do with AI. But I don't see a problem for science there.
I wrote, "If you are correct, you can demonstrate that you are." Even a link to a prior demonstration would suffice. I'm looking for one of the foundational beliefs you say has been shown to be untrue by experiment. Do you think that you did that here? I don't, which is why I am still looking.
If by believers you mean empiricists, almost none say that. I've never seen it.
Perhaps they do not understand what it means to demonstrate something. Or perhaps, as seems common among belief-based thinkers, they believe that any unsupported opinion or empty assertion they render is a demonstration of the fact of what is asserted.