 In the DTO approach, the essential properties/tropes of a trope bundle are then identified with the defining characteristics of a superselection sector, such as different kinds of charges, mass and spin. Since these properties cannot change by any state transition they guarantee the object’s identity over time. Superselection sectors are inequivalent irreducible representations of the algebra of all quasi-local observables. While the essential properties/tropes of an object are permanent, its non-essential ones may change. Since we are dealing with quantum physical systems many properties are dispositions (or propensities); hence the name dispositional trope ontology.