@layman,
layman: " Well, sure, and I expect PP would agree with you on that (but maybe not, who knows). I think he was using "text" as a synonym for "information" or "meaning." That's "carried by" the text, but it aint the same thing. One is a physical object, one aint."
Good paraphrase but I'd go further. Text is a type of symbol, whether ink on paper, carving in wood or stone, or smoke from a skywriting plane; and symbols exist only when someone recognizes them as such. That's true even when convention (agreement between two or more parties) doesn't exist. If I have a sleeping dream and see something that I recognize as a symbol and it means something to me, even though I never learned such a symbol in school, then it's a symbol to me.
If I'm walking along and it looks like somebody has carved initials into a tree I might call that text. If I get closer and see it's moss, I might change my mind and call it coincidence. f I get closer still and find that it's moss but it has been trimmed with a penknife to look like initials, I might change my mind again and call it text. And if I wake up after dreaming this improbable series of events?
What if someone's handwriting or printing is so lazy that it looks like one thing to me but the writer says it's something else; or a letter or digit is so stylistically ambiguous that it could be reasonably regarded as either of two things? What if I wake up after dreaming this and the putative intent of the other person (the writer) evaporates? What did it really say? Was it even text?