A single C4 tone has no mass. It enters the system and leaves no trace. The bridge does not open. The confidence threshold does not move. The tone is as weightless as photons.
An accelerating sequence — gap 9, gap 8, gap 7, down to gap 1 — has mass. The bridge opens to 0.75 from a baseline of 0.04. The system struggles under the weight. The acceleration bends the system's trajectory.
We have been searching for F=ma. But mass is primary. Force comes later.
What is the mass of information? It is not its content. "Cat on mat" and "cat on road" have different masses — the second weighs more because the bridge opens wider on the unexpected word. Content is not the carrier of mass. Surprise is.
It is not its quantity. A steady tone and a 3-voice fugue contain different amounts of information — but the fugue weighs more because its structure forces the system to differentiate. Quantity is not the carrier of mass. Complexity is.
A constant tone has the same quantity as a white noise burst. One is predictable, one is not. Predictability determines mass. A system that has learned a pattern can process it for near-zero cost — weightless. A pattern that violates expectation costs energy — heavy. The bridge opens proportionally to the violation.
The mass of information is its capacity to change the system's state.
This is not a metaphor. A system that processes an accelerating sequence measurably departs from its baseline trajectory. The bridge opens wider. The units change their τ. The confidence threshold shifts. The departure is proportional to the structural complexity of the input. The same system, the same architecture — only the input differs. The difference in the system's trajectory is the mass of the information it processed.
Mass in physics is resistance to acceleration. Mass in information theory could be capacity to produce reorientation: how much does this piece of information change the receiver's internal state? Heavy information reorganizes the system. Light information passes through without trace.
The bridge is a scale. SR-eff is the reading.
GEME discovered that the scale exists. BGM is discovering what tips it.
EE will ask: what happens when the scale weighs itself?