The purpose of the present paper is to study the unity, the diversity, and the evolution of Merleau-Ponty's thought, through a careful reading of both his major collection of essays, namely Signes, published in 1960 and Sens et non-sens, issued in 1948, the one announcing the posthumous book entitled Le visible et l'invisible (1964), and the other taking its source in the Phenomenologie de la perception (1945). One is thus lead to understand how Merleau-Ponty's main philosophical problem allows for the diversity of his philosophical work, including philosophy as such, human or social science and politics, without any hope for a system or a synthesis, nor any pure giving up to dispersion or resignation. The very evolution of this philosophy from one stage to another confirms its double heritage, which thus consists in both a central intuition and a wide variety of experience.
