We intend to show that the philosophy of Merleau-Ponty embodies the fundamental experience of the dialectic: To bring concept to the meaning of things, the world, from the others, through an experience (Er-fahrung) expression that does not convert the sense of these in a simple result of its reflection. Ear him this dialectic is resolved as negative dialectic, in the sense of being a philosophy that thinks the negative in a radical sense, that is, as a denial that is a constitutive part of the positive, integrated to this one in an essential way We see, in particular, that this idea of the dialectic crosses a new conception of new thinking as sensible thinking sensitive or 'chiasmus '. The text consists of the following sections: I. Negative dialectic, 2. The dialectic as reunion with the past; and, 3. The sense of criticism.