Actually, this seems like a General Semantics meets Bayes kind of principle. Surely Korzybski had a catchy phrase for a similar idea. Can anyone got one?

Korzybski did "turgid" rather than "catchy", but this seems closely related to his insistence that characteristics are always left out by the process of abstraction, and that one can never know "all" about something. Hence his habitual use of "etc.", to the degree that he invented abbreviations for it.