Phenomenology played a central role in twentieth-century philosophy. But, from the second half of the century, many alternative philosophical movements emerged. Despite their radical criticism of phenomenology, they regularly touched upon themes that had been originally propounded by phenomenology itself. This is true of Jacques Derrida, Michel Foucault, and Gilles Deleuze. At the basis of their approaches, there is the need for a new version of the transcendental, the idea of an impure transcendental, and the intuition of a non-transcendental structure of the transcendental, which they all name “difference.” Phenomenology could draw useful insights from these perspectives: e.g., a more continuous view of the range of psychopathological experiences; a more exact comprehension of the different temporal and spatial structures of psychopathological worlds, as the internal possibilities and infinitesimal variations of the transcendental; and a more critical way of thinking through the structure of institutions and the normativity that dominates them.