In fact, says Eco, every major linguistic code is 'a complex network of subcodes'. With model Q, therefore, the code is modified in accordance with the changing competencies of language users, instead of being determined by the code. The other side of a theory of codes is a theory of sign production. The closer one comes to ratio difficilis, the more the sign of the object is 'motivated' by the nature of the object itself. Icons are the category of sign which bring this out most clearly.
Examples are emblems, musical types, mathematical signs.
Instead of being closed and static, Eco's argues that the sign system is open and dynamic. A comparable motivation is evident in Eco's discussion of signs and signification in Semiotics and the Philosophy of Language . As we have noted above, the view of interpretation in operation here is that of Peirce's 'interpretant', which gives rise to unlimited semiosis. The key theme in Semiotics and the Philosophy of Language concerns the difference between the structure of the dictionary and the encyclopedia. The dictionary model of language would thus fail to account for unlimited semiosis.