Abstract

Non-reflexive logics are systems of logic in which the reflexive law of identity is restricted or violated. The most well-known of such systems are Schrödinger logics and quasi-set theory; both are related with the metaphysics of quantum mechanics, aiming at formalizing the idea that quantum entities are non-individuals. We argue in this paper that non-reflexive logics may be seen as attempting to characterize two metaphysically incompatible notions of non-individuals: (i) non-individuals as violating self-identity and (ii) non-individuals as indiscernible entities. The problem is that any choice between these options brings difficult questions, making the understanding of non-individuals through the apparatus of non-reflexive logics rather implausible.