 There remain other substantial questions about functionalism. Most discussions of the prospects for functionalism focus on its adequacy as an account of familiar experiential states such as sensational and perceptual experiences, and familiar intentional states such as beliefs and desires. But although some philosophers have considered whether there can be adequate functionalist characterizations of emotions and moods (e.g. Rey, 1990, Nussbaum, 2003, deHoog, et al, 2011) there is increasing interest in these questions, and more work needs to be done. In addition, there is increasing interest in determining whether there can be plausible functional characterizations of non-standard perceptual experiences, such as synaesthesia, and various sorts of altered states of consciousness that can arise from the ingestion of drugs or from focused meditation. (See Gray et al. 2002, 2004, and Deroy, 2017, for discussions of synaesthesia. For general discussions of altered states of consciousness, see Velmans and Schneider, eds. (2007), and Thompson, (2015).