We often speak in sociology, referring to Norbert Elias or Pierre Bourdieu, of a “relational mode of thinking” or of a “relational sociology”, suggesting that the relational character would be a scientific strategy among others, certainly fruitful, but conceived in a nominalist perspective as a pure point of view on the real or as a method. The extension of the framework of observation to the whole of the living world (and one could say to the whole of reality, if one considers that the physical reality is also relational) shows that interdependence is a universal fact of nature and that if “relational thinking” is a heuristic scientific strategy that pays off, it is because, as Bourdieu says on occasion in a clearly realist vein, “the real is relational”. The fact that the sciences of matter as well as of life have never ceased to highlight the relational character of reality leads us to think that there is no science in general, and no social science in particular, that is not relational, and that this should not constitute an option among other possible options, but a basic postulate of all research.