The German physicist whose 1900 quantum discovery recurs in the series first as one of the simultaneous 1900 breakthroughs, then as an argument in its own right. Cameron uses what he calls the Planck limit — that pressing toward the final answer discloses a boundary rather than crossing one — as the physical-science analogue of why metaphor resists clarification. New to it — start with dialogue 58.
Across the dialogues
Promoted from a date on the 1900 list of simultaneous breakthroughs into an argument the pair actually run — the limit stops being period colour and becomes the physics proof that metaphor cannot be clarified, which is then turned against the pipeline model of communication
The limit is introduced as a discovery about the world rather than about instruments — approaching the answer displaces it, so discreteness is a feature of reality.
"That's the Planck limit."
The transfer that makes the physics matter here — what stops thought short is the same thing that makes metaphor work, so clarifying a metaphor is not refining it but dissolving it.
"That limit is metaphor."
Connections
Cameron uses the Planck limit to argue that metaphor is the limit that cannot be crossed or clarified.
The limit is what defeats the Shannon pipeline model of communication — as A approaches B, there is no carrying across.