In a widely discussed article, 'Mind-Body, identity, Privacy and Categories', 1 Richard Rorty set forth a new approach to the Identity Theory of the Mind. Instead of attempting to equate sensations and certain neural events, Rorty claims that in the future we may cease to speak of sensations at all. If the phenomena now explained by reference to sensations could be better explained by laws that mention only neural events, then we might eliminate the concept of sensations just as we rejected the idea of demons. Because the sensations are simply eliminated or replaced by neural events, rather than equated with certain neural events, as they have been in the Identity Theory, Rorty labels his view the 'Disappearance' version of the Identity Theory.
Now critics argue that we cannot replace terms designating sensations with ones designating neural events, because the former are observation terms and the latter are theoretical terms. Rorty counters with the argument that the distinction between observable intities and theoretical ones is relative to a particular set of linguistic conventions, which could be changed under the impact of the new laws explaining mental phenomena in terms of neural events. So there is no reason in principle why neural events could not come to be construed as fit subjects for observation reports. Assuming that specific types of sensations are invariably correlated with specific types of neural events, then the coiditions under which we previously made the former types of observation reports will be precisely the same as those under which we would make the latter type of reports. "We will, indeed, have been making noninferential reports about 'brain-process' all our lives sans le savoir." 2 Rorty illustrates how such a change in linguistic habits could be produced. Suppose... that we find it convenient to speed up the learning of contrastive observation predicates (such as 'painful', 'tickling', etc.) by supplying children with portable encephalographs-cum-teaching-machines which, whenever the appropriate brain process