The descriptive procedures of "narratology" and the notion of "narrativity" are at the very base of Greimassian semiotics of discourse. His initial hypothesis is that meaning is only apprehensible if it is articulated or narrativized. Second, for him narrative structures can be perceived in other systems not necessarily dependent upon natural languages. This leads him to posit the existence of two levels of analysis and representation: a "surface" and a "deep level", which forms a common trunk where narrativity is situated and organized anterior to its manifestation. The signification of a phenomenon does not therefore depend on the mode of its manifestation, but since it originates at the deep level it cuts through all forms of linguistic and non-linguistic manifestation. Greimas' semiotics, which is "generative" and "transformational", goes through three phases of development. He begins by working out a "semiotics of action" ("sémiotique de l'action") where "subjects" are defined in terms of their quest for "objects", following a "canonical narrative schema", which is a formal framework made up of three successive sequences: a "mandate", an "action" and an "evaluation". He then constructs a "narrative grammar" and works out a syntax of "narrative programs" in which subjects are "joined up with" or "separated" from objects of value. In the second phase he works out a "cognitive semiotics" ("sémiotique cognitive"), where in order to perform, subjects must be "competent" to do so. The subjects' competence is organized by means of a "modal grammar" that accounts for their existence and performance. This modal semiotics opens the way to the final phase that studies how "passions" modify actional and cognitive performance of subjects ("sémiotique de passions") and how belief and knowledge modify the competence and performance of these very same subjects.