 Functionalist theories of all varieties — whether analytic or empirical, FSIT or functional specification — attempt to characterize mental states exclusively in relational, specifically causal, terms. A common and persistent objection, however, is that no such characterizations can capture the phenomenal character, or “qualia”, of experiential states such as perceptions, emotions, and bodily sensations, since they would leave out certain essential properties of those experiential states, namely, “what it's like” (Nagel 1974) to have them. The next three sections will present the most serious worries about the ability of functionalist theories to give an adequate characterization of these states. (These worries, of course, will extend to intentional states, if, as some philosophers argue, “what it's like” to have them is among their essential properties as well. (See Searle 1992, G. Strawson, 1986, Horgan and Tienson, 2002, Kriegel 2003, Pitt 2008, for early presentations of this view, and see Bayne and Montague, 2011, and Smithies, 2013a and 2013b for more general discussions of whether intentional states possess phenomenal character— often called “cognitive phenomenology”— and if so, what, more precisely, it is.)