The principle of identitas indiscernibilium can be thoroughly expressed in a quantum context, overcoming the debate about the possibility of distinction among identical entities according to space-time parameters: the symmetry defined by the exchange of the wave function without overlapping describes the behavior of particles as if they were alike. That nature of the wave function is depicted along the essay as a relational property of observation, not of the quantum object itself, making the principle take an epistemological turn, dissociated (...) from the object ontic drive. (shrink)