He proposes that one looks at how linguistics have done, and study structures beyond the sentence. Narratives, as an example of structures of meaning, can be studied on different levels of description. Terms acquire meaning not in isolation, but in relationship with other terms, on the same level, and on different levels. Narratives are a hierarchy of instances. Functions are the smallest unit of narrative, something that may not have meaning directly but which acquire meaning in combination with other units, on the same level or on a higher level.
Functions can in some cases be shorter than the sentence, even parts of a word.
A unit can belong to more than one class. Informants and indices can combine freely. A catalyser implies the existence of a nuclei to which it can connect. Nuclei are bound together by a relation of solidarity. A sequence is a logical succession of nuclei bound together by a relation of solidarity.