Identity Theory in the Perspective of Quine' s Ontological Commitment

As a significant concept in the field of philosophy of logic, identity plays a key role in Quine's Ontological Commitment Theory. Quine uses the quantitative method of predicate logic to study the ontological problem, and puts forward the ontological commitment standard that "To be is to be the value of a variable". The bound variable becomes the only device that undertakes the ontological commitment ftinction. The value of the bound variable is the entity of the ontological commitment made by the theory in which it is based. However, Quine argues, not all objects can be the values of the bound variable and thus the entities that the theory promises to exist. Quine takes the concept of identity as a necessary condition of ontological commitment, that is,"no identity, no entity". In Quine's view, the concept of identity refers to the identity between extended objects, rather than the identity between connotative objects and possible objects. As the core concept of Ontological Commitment Theory, the concept of identity has a profound influence on Quine's philosophy.