Disjunctivism and the Causal Conditions of Hallucination

Abstract

Disjunctivists maintain that perceptual experiences and hallucinatory experiences are distinct kinds of event with different metaphysical natures. Moreover, given their view about the nature of perceptual cases, disjunctivists must deny that the perceptual kind of experience can occur during hallucination. However, it is widely held that disjunctivists must grant the converse claim, to the effect that the hallucinatory kind of experience occurs even during perception. This paper challenges that thought. As we will see, the argument for thinking that the hallucinatory kind of experience is present even in cases of perception depends on prior acceptance of a ‘non-demanding’ conception of hallucination, on which all it takes to produce an hallucinatory experience is to induce in the subject the right kind of neurological condition. On the view developed here, by contrast, there are substantive causal conditions, going beyond the mere occurrence of the right kind of neurological state, that must be met if an experience of the hallucinatory kind is to occur. By drawing on this view, I argue, disjunctivists can deny that the kind of experience involved in hallucination ever occurs during perception. This then allows disjunctivists to avoid certain important problems they would otherwise face. It also leaves them with considerably more freedom when it comes to theorising about the nature of hallucinatory experience.