The distinction has no standard name in information theory because Shannon's framework was designed for systems where the receiver is a machine that only needs the destination signal. In human-machine communication, the receiver is a mind that learns from the transmission process itself, and channel signal has independent value.
The phenomenon explains the geological understanding loss that senior practitioners describe after extended AI-assisted work. Their mental models stopped receiving the high-entropy inputs — failed hypotheses, unexpected errors, debugging surprises — that maintained and updated them. The models decayed not through forgetting but through the absence of the surprise-carrying interactions that had kept them current.
The mathematical formulation suggests a response the philosophical critique of smoothness alone does not: deliberate practices of seeking surprise can recover channel signal without sacrificing the throughput gains of the smooth interface. An engineer who uses Claude to generate a function, then deliberately attempts to break it, tests edge cases, and examines the generated code for unspecified assumptions, is reintroducing entropy into the channel — generating the incidental information the smooth process suppressed.
The shift is from involuntary to voluntary surprise generation. The original debugging process produced surprises automatically because failure was forced by the environment. The supplementary practice requires deliberate effort because the tool has removed the failure-forcing friction. The practice is harder to sustain precisely because it is optional.
The distinction is implicit in Segal's You On AI analysis of what smooth interfaces eliminate. Its formalization in Shannon-theoretic terms is recent — an attempt to specify mathematically what the philosophical critique of smoothness has been gesturing at.
Two signals, not one. Every transmission process produces both the intended artifact and incidental information about the system that produced it.
Traditional pipelines delivered both. Debugging, code review, and iterative development transmitted destination signal (working code) and channel signal (system understanding) simultaneously.
Smooth interfaces preserve destination, suppress channel. The AI collaboration delivers the artifact and eliminates the byproduct education.
Channel signal is where expertise lives. The geological layering of expert mental models is built from accumulated channel signal, not from artifacts alone.
Deliberate practice recovers channel signal. Voluntary surprise-seeking — testing edge cases, breaking what works, examining what was generated — restores some of the lost byproduct information.