objects are not wholly present at any single instant of time; instead, some temporal parts is said to be present. Sometimes, especially in the theory of relativity as it is expressed by Minkowski, the path traced by an object through spacetime. According to Ted Sider, “Temporal parts theory is the claim that time is like space in one particular respect, namely, with respect to parts.” Sider associates endurantism with a C-relation between temporal parts. Sider defends a revised way of counting. Instead of counting individual objects, timeline slices or the temporal parts of an object are used. Sider discusses an example of counting road segments instead of roads simpliciter. (Sider 2001:188-192). (Compare with Lewis 1993.) Sider argues that, even if we knew that some material object would go through some fission and split into two, "we would not say" that there are two objects located at the same spacetime region. (Sider 2001:189) How can one predicate temporal properties of these momentary temporal parts? It is here that the C-relation comes in play. Sider proposed the sentence: "Ted was once a boy." The truth condition of this sentence is that "there exists some person stage x prior to the time of utterance, such that x is a boy, and x bears the temporal counterpart relation to Ted." (Sider 2001:193) Counterpart theory and the necessity of identity Kripke's three lectures on proper names and identity, (1980), raised the issues of how we should interpret statements about identity. Take the statement that the Evening Star is identical to the Morning Star. Both are the planet Venus. This seems to be an a posteriori identity statement. We discover that the names designate the same thing. The traditional view, since Kant, has been that statements or propositions that are necessarily true are a priori. But in the end of the sixties Saul Kripke and Ruth Barcan Marcus offered proof for the necessary truth of identity statements. Here is the Kripke's version (Kripke 1971): (1) [Necessity of self-identity] (2) [Leibniz law] (3) [From (1) and (2)] (4) [From (3) and the following principle: ] If the proof is correct the distinction between the a priori/a posteriori and necessary/contingent becomes less clear. The same applies if identity statements are necessarily true anyway. (For some interesting comments on the proof, see Lowe 2002.) The statement that for instance “Water is identical to H2O” is (then) a statement that