In Saussure's linguistic theory, the idea of a sign being "immutable" means that the relationship between the signifier (sound image) and the signified (concept) within a linguistic sign is considered fixed and unchanging within a language system ("langue"), even though individual uses of language ("parole") may vary; essentially, the meaning of a word is determined by its place within the overall structure of language, not by individual interpretations or spontaneous changes.
Key points about Saussure's "immutable" sign:
System-based meaning:
The value of a sign is derived from its position within the network of other signs in the language system, not from any inherent quality.
"Langue" vs "parole":
While individual speech acts ("parole") can seem fluid and dynamic, the underlying system of signs ("langue") is seen as relatively stable and unchanging.
Criticism of the "immutable" concept:
Later linguistic theories, particularly post-structuralist approaches, challenge the idea of a completely fixed and stable sign, highlighting the dynamic nature of language and the possibility of meaning being constructed through interpretation and context.