 Now, Kripke is of course not trying to put forward an account of fundamentality here, but rather to specify that the qualitative experience of feeling heat is something additional to molecular motion. The idea, however, is strikingly close to the primitivist account of fundamentality, whereby the important thing is to find a sufficiently rich basis for everything in the world—this is of course reminiscent of  (CMB),  but here the heuristic is simply used to characterize fundamentality, not to define it.