Bill Vallicella draws a conclusion:
So any sense or reference linguistic signs have must be derivative and relational as opposed to intrinsic.
This is right, and Vallicella’s proof is sound – what I’m musing over is what happens when we link it up with another premise:
Any entity can be made to signify, either in a language or at least ad hoc
Any entity, whether physical or immaterial, could be made a signal or sign that something is to be done. But if this is true, then mind is set outside not only the physical, but even outside of entity as such. But it would be ridiculous to take this as a sign that mind has no existence at all. The entity is only itself; the mind is both within itself and outside itself: within so far as it has entity; outside so far as even that entity could be taken as signifying.