Mean Molecular Kinetic Philosophy Question

Context: At the end of Naming and Necessity, Kripke discusses the thesis that mental states and processes identical with, and so nothing more than, physical states and processes. One such supposed identity is (2), which he compares to (1).

1. Heat is mean molecular kinetic energy.

2. Pain is C-fiber stimulation.

Here, we treat the nouns as designating kinds (rather than their instances), and ‘is’ as expressing identity. Both sentences are aposteriori, and so may appear contingent. Kripke argues that the seeming contingency of (1) is an illusion. He takes ‘heat’ and ‘mean molecular kinetic energy’ to be rigid designators, in which case (1) must be necessary, given that it is true. The illusion of contingency is attributed to the fact that we identify heat by the sensations it causes in us. Thus, he thinks, ‘heat’ is associated with “the reference-fixing-description,” ‘the cause of sensation S’. The illusion that (1) is contingent comes from confusing this description with a synonym for ‘heat’, and thereby confusing (1) with (1*).

1*. The cause of sensation S = mean molecular kinetic energy.

But ‘heat’ isn’t really synonymous with ‘the cause of sensation S’. Once the non-equivalence of (1) and (1*) is recognized, the contingency of (1*) no longer masks the necessity of (1).

Kripke assumes that, like the terms in (1), those in (2) are rigid, and hence that (2) is necessary, if true. This time, however, he sees no way of dismissing the impression of contingency as an illusion. Unlike ‘heat’, which we use to designate the cause of a certain sensation, ‘pain’ is used to designate the very sensation we notice. We don’t say to ourselves: “What a horrible sensation! Let’s use ‘pain’ to designate whatever causes it.” Instead, ‘pain’ designates the sensation, which we identify directly, without appeal to properties that anything else could have. Because there is no descriptive reference-fixer to confuse with a synonym for ‘pain’, there is no contingent claim to confuse with (2). Since the intuition that (2) is contingent can’t be dismissed as an illusion, Kripke suggests that (2) isn’t necessary, and so isn’t true.

Scott Soames criticized this argument in 2006. Nevertheless, he maintained that Kripke’s observation that being a pain is an essential property of anything that has it constitutes a plausible objection to leading versions of the mind-body identity theory, such as that of David Lewis.

Question: In at least 2000 words, explain and evaluate the views of Kripke, Soames, and (very briefly) Lewis on these points.

Readings to be used in the paper:

S. Kripke, Lecture 3 of Naming and Necessity, pp. 148-155. http://people.exeter.ac.uk/sp344/naming_and_necess…

Soames, “Kripke on Mind-Body Identity; https://dornsife.usc.edu/scottsoames/selected-publ…

D. Lewis, “Mad Pain and Martian Pain,” Collected Papers, Volume 1. https://static1.squarespace.com/static/5b714a23620..