Epistemologic obstacles in relation with the way of analysing the passage between the real object of mourning and the interiority of its pathos might have contributed to insufficient development of the subject of mourning in psychoanalysis. Its development is not in accordance with its psychopathologic importance. The author thinks that a logic of paradoxality and negativity enables to take into account the differenciation between external and internal reality, and at the same time to integrate external reality into the analysis. The negativity is constituted, among other aspects, by the complexe zone of exchanges between external reality of mourning and internal reality. The model of mourning is an example of methodologic importance of a logic of paradoxality and negativity which enables limits of models to become permeable. Thereby specificity of the model and integration of the reality of the mourning object are both taken into account.