Abstract

The Principle of the Identity of Indiscernibles (PII) asserts that if putative objects x and y share all properties P, then they must be one and the same entity. Since the usual formal rendering of the PII has the same formal structure as the Leibniz Identity, it may be unclear whether it can be used to define identity and objectuality. As identity and objectuality are closely related, this study aims to examine their relationship within the framework of formal ontology. Crucial for the discussion are issues about type and range of quantification and the invariance of the identity predicate coourring in the PII. Ultimately, the analysis reveals that the appeal to PII is insufficient for providing both identity and objectuality. Some further considerations about how the PII sensitively constrains the range of available ontologies or metaphysics are formulated.