Is the statement "Claims demand evidence" always true?

[Mudhammam]

In the end, we play word games, and believe that the words represent something real-- even "spin words" like "justification".  But as soon as we spin a foundation, no matter how plausible it seems to us, we spin an entire universe-- our world view-- out of words and little more, because it all stands on that foundation.

I don't think that's the case.  It's true that our sounds and symbols have largely developed atop of a series of accidents, but where truth is concerned, it's not accidental that the words we have selected represent the concepts that they in fact represent; the particular words are inconsequential. So, when you say:

This is humanity's greatest achievement, I think: to live in a world completely imagined, and to manage not to know so.  For whatever is "out there," it cannot be what is "in here."  And what else do I have?

...I hear you saying something like, "We imagined that the atomic number of gold is 79," but that's not true.  That's an essential property of gold, whether or not we call it such, or change our symbols so that what is currently represented by putting "7" and "9" together is represented by some other lines and squiggles.  Is there an important distinction between "in here" and "out there" to be made here? I'm doubtful.  For, in so far as we have subjective experiences in an objective reality, what's "in here" is often representing what is "out there," and "out there" in an unrepresented sense that is wholly separate from the properties we perceive is either nonexistent or unknowable in terms (as it exists in-itself) that I can't conceive to be of any consequence that isn't trivial.