Since 1850, researchers have turned to the most ancient past and the origins of man. Evolutionism is at the heart of reflections. Questions about the unity of the human race and the reasons of cultural differences abound. It is important to know why, if the whole humanity is subject to the same historical movement, some societies have progressed, while others seem to be set rigidly in an irremediable primitivity. In this context, the idea of race develops, as well as the idea of difference (that-is-to say of inegality) that is biologically given- a notion set to account for the cultural stagnation of the non-occidental populations. It is against this background that the Mesolithic periodization was brought to light, at the very moment of th...