Kripke's Pain Is C-Fiber Stimulation

Kripke argues that all identity statements are necessary, and not contingent. A theoretical identity statement that is necessarily true means it is true and it could not have been otherwise. A contingent identity statement is one that is true in this world, and that there is one possible world out there that it does not hold true, and it is possible that it would and could have been otherwise. If pain is C-fiber stimulation, then it is necessarily true that pain is C-fiber stimulation and it could not have been otherwise in all possible worlds. Thus, the identity statement “Pain is C-fiber stimulation” is necessarily true. However, it is conceivable that there is one possible world in which pain is not C-fiber stimulation. If that is true,
The terms “pain” and “C-fiber stimulation” are rigid designators. A rigid designator refers to a term that designates the same object/phenomenon in all possible worlds in our own language, provided that the object/phenomenon does and would exist in the first place. The terms “pain” and “C-fiber stimulation” both refer to the same external phenomenon in all possible worlds. Thus the identity statement “pain is C-fiber stimulation” is necessarily true. In other words, one cannot imagine that “pain” is not identical to “C-fiber stimulation” in any other possible world. However, one can imagine that in one other possible world, “pain” is not identical to “C-fiber stimulation”, thereby showing that the statement “pain is C-fiber stimulation” is
To have an illusion of contingency is to misunderstand a theoretical identity statement that is necessary to be contingent. In other words, it is false to think that pain is not identical to C-fiber stimulation because one might have the same illusion that heat is not identical to the motion of molecules. Kripke’s statement “For a sensation to be felt as pain is for it to be pain” shows that there is no such illusion when it comes to the identity of pain. If one conceives of heat without the motion of molecules, one is actually identifying heat by picking out a contingent property of heat. On the other hand, one does not identify pain by picking out a contingent property of pain because pain itself is an essential property of pain. One identifies pain by feeling pain. In other words, to feel pain is for pain to be pain. The sensation of pain exists with or without any particular brain states. For example, empirical science may have already established that C-fiber stimulations do indeed trigger the sensation of pain. If one were to follow the identity theorist’s logic, if C-fiber stimulations occur and no pain is felt, then it means that pain does not exist. However, pain exists in and of itself. The sensation of pain, and not