Quine on Personal Identity

The problem given in the question “Can you bathe in the same river twice?” is that since the substance of the river is constantly renewed, it would seem that it is not the same river, and so our words, that is the names we give the things we are trying to describe, are too vague to denote that this is a river. The same is true of similar examples, such as the ship of Theseus. 

Quine’s answer to the problem is to say that these questions don’t really concern the nature of identity, but rather, they concern what we choose to count as a river, a boat, or a person. What makes gives something the nature of identity is not that they have the same river stage or same river substance, but that it is a process of continually replacing the substance or stages of time. So we may be tempted to point at the Ganges River at two different times and say that because of the constant change of substance they are not both the Ganges River, but all that would be true here is that you are pointing at two different time stages of the same river, or river-ish summation of momentary objects. Quine will say you bathe in the same river twice, but not the same river stages. And so it goes with persons.