Warren Weaver's three levels of problems in communication (1949)

Level A.

How accurately can the symbols of communication be transmitted? (The technical problem.)

Level B.

How precisely do the transmitted symbols convey the desired meaning? (The semantic problem.)

Level C.

How effectively does the received meaning affect conduct in the desired way? (The effectiveness problem.)

There is a close relation between these levels and the semiotic distinctions:

A:

Syntax and the forms of language.

B:

Semantics and the meanings of language.

B:

Pragmatics and the use or function of language.