David,
You're right, people always trot out Piaget at this point, and make him jump through a few hoops, along with brain damage, beetles in boxes, and anecdotal testimony. Personally, I wonder about the practical value of the question. How would we even know?
On the original subject though, and from a pragmatic point of view, we're stuck with Morton's fork. Either we go with direct statement, or head for metaphor. But direct statement is never clear, if the Richards/Emerson crowd is right, and all we're left with is misunderstanding.
And if we decide to go with metaphor, then we're really in trouble. Either no metaphor is true (after all, one thing is not another thing), or every metaphor is so true (since all is one, and everything is everything else) that any particular metaphor is meaningless.
But there must be a third choice, something besides misunderstanding and meaninglessness. It's the only pragmatic option. I just have no idea what it is...
Thanks,
Bill