Questions of Identity ( II )

In Tractatus, Wittgenstein says that “to say of two things that they are identical is nonsense, and to say of one thing that it is identical with itself is to say nothing.” This seems to make all the discussion about identity trivial; is there anything that can be said about identity? The extensive discussion about identity demonstrates that the notion of identity is far from trivial. Think, for example, identity of an entity over time or personal identity. The notion of individuation, or let us say identification, is a key notion for Quine in explicating his wording “no entity without identity”. The notion allows us to analyse and answer questions such as the following: How to know the identity of an individual? What kinds of constraints does such identification knowledge suppose? Identification means locating an individual on some framework. However, the notion of identification may not be confused with the notion of reference: the relationship between the notions of identification and reference is reminiscent of the relationship between Frege’s notions of Sinn and Bedeutung. To make the notion of identification explicit, we will use the possible-worlds semantics, which interconnects us to more general philosophical discussion. Using possible-worlds semantics we can explicate different methods of identification or cross-identification, as well as physical and perceptual methods, which allow us to analyse the notion of identity more deeply. This approach is philosophically important but it also has several methodological implications to empirical science.