Individuality, distinguishability, and (non-)entanglement: A defense of Leibniz׳s principle

•GMW-(non-)entanglement in terms of individuality and distinguishability.•Connection of (in)distinguishability with ontology and labeling.•Defense of Leibniz׳ s Principle (PII) for similar fermions.•Summing defense of PII for entangled fermions.

The paper provides a philosophical interpretation of Ghirardi, Marinatto, and Weber׳s physical criterion of (non-)entanglement in terms of individuality and distinguishability. It firstly clarifies the relation between ontology and labeling, and then defends the non-standard view that non-similar particles and similar fermions are individuated by a traditional version of Leibniz׳s principle of the identity of indiscernibles. It will be argued that Leibniz׳s principle is satisfied explicitly in non-entangled states, whereas in entangled states it can be defended via the summing defense.