General Semantics is a discipline founded by Polish-American scholar Alfred Korzybski that studies how language and other symbols shape human thinking and behavior, summed up in his dictum "the map is not the territory."
Korzybski introduced General Semantics in his 1933 book Science and Sanity: An Introduction to Non-Aristotelian Systems and General Semantics. He argued that people routinely confuse words and abstractions with the realities they stand for, and that this confusion drives misunderstanding, conflict, and poor judgment. His remedy was training people to become conscious of abstraction, the process by which the nervous system and language select and simplify from experience.
Its core ideas are that the map is not the territory, the word is not the thing, and no map covers all of its territory. Korzybski challenged the Aristotelian "is" of identity and rigid either/or thinking, and proposed practical devices such as indexing (chair1 is not chair2), dating (Smith1933 is not Smith1937), and "etc." to mark every description as incomplete. He held up mathematics as the language whose structure most closely matches the structure of the world.
Korzybski founded the Institute of General Semantics in Chicago in 1938 and taught intensive seminars, including a 1937 series at Olivet College in Michigan that was later published as a transcript. His work influenced S. I. Hayakawa's Language in Thought and Action and Albert Ellis's rational emotive behavior therapy.
Pirsig pointed me to Korzybski, and I read and reread his 1937 Olivet College lectures until I felt I was in the audience. I extend his line: the map is not the territory, the word is not the thing, the financials aren't the business. When I find too many Platypuses in my language, it's time to question my first principles.