Hallucination, edited by Fiona Macpherson & Dimitris Platchias, Cambridge (Mass.): The MIT Press, 2013, pp. 175-220.
One central fact about hallucinations is that they may be subjectively indistinguishable from perceptions. Indeed, it has been argued that the hallucinatory experiences concerned cannot – and need not – be characterised in any more positive general terms. This epistemic conception of hallucinations has been advocated as the best choice for proponents of phenomenal (or ‘naive realist’) disjunctivism – the view that perceptions and hallucinations differ essentially in their introspectible subjective characters. In this chapter, I aim to formulate and defend an intentionalist alternative to phenomenal disjunctivism called experiential intentionalism. This view does not only enjoy some advantages over its rival, but also can largely hold on to the epistemic conception of perception-like hallucinations.
First of all, I try to spell out in a bit more detail in which sense hallucinations may be subjectively indistinguishable from perceptions, and why this leads us to erroneously judge them to be perceptions (cf. sections I–III and VIII). Then, I raise three challenges each for phenomenal disjunctivism and its orthodox intentionalist counterparts (cf. sections IV and V), notably in respect of the need to explicate why a perception-like hallucination still makes the same judgements reasonable for the subject as the corresponding perceptions. And, finally, I propose my alternative both to phenomenal disjunctivism and to orthodox intentionalism. Experiential intentionalism takes perceptions and perception-like hallucinations to share a common character partly to be spelled out in intentional – and, hence, normative – terms (cf. sections VI and VII). The central thought is that the hallucinations concerned are intentionally – and erroneously – presented to us as perceptual relations to the world. I aim to show that the resulting view can meet all six challenges (cf. sections VI–VIII). I end with some comments on the consequences for the nature of perceptual experiences (cf. section IX).
Experiential intentionalism is compatible with the epistemic conception of hallucinations, as well as with the disjunctivist view that perceptions and hallucinations differ essentially in their third-personal structures (e.g., their causal, informational or reason-providing links to reality). It also maintains that there are actually two aspects to the subjective indistinguishability of mental episodes: (i) that we cannot distinguish their first-personal characters in introspective (or reflective) judgement; and (ii) that we cannot distinguish their third-personal structures in experiential (or phenomenal) awareness – that is, in how they are given to consciousness. While phenomenal disjunctivism makes the mistake of ignoring (ii) and reducing subjective indiscriminability to (i), experiential intentionalism correctly identifies (ii) as the primary source of the subjective indistinguishability of perception-like hallucinations. Accordingly, the intentional error involved in such hallucinations is due to the fact that we consciously experience them as possessing a relational structure.