Critics of disjunctivism have argued that the disjunctivist needs to provide a plausible explanation of just how two distinct mental states might be indistinguishable for their subject without simply taking the fact of indistinguishability for granted. This chapter examines the everyday notion of indistinguishability alongside relevant empirical findings. It offers an account of hallucinatory indistinguishability which suggests that the indistinguishability of hallucination from veridical perception is grounded in the similarity of their effects, rather than in any phenomenal similarities between the two states. This analysis is then elaborated to show how it can account for the first-person aspects of hallucinations, to show how it is possible for conceptually unsophisticated creatures — such as animals and infants — to hallucinate, and to show how a subject may suffer from hallucinations whilst being aware that their experiences are non-veridical.
Keywords: perception, phenomenal character, animals, children, veridical