Istvan Aranyosi "Silencing the Argument from Hallucination"

One of the more recent replies to the argument from hallucination is disjunctivism, whose main tenet is that although there are possible hallucinations that are subjectively indistinguishable from veridical perception, the two mental states –that of hallucinating an object and that of perceiving an object—are of different kinds, having nothing substantial in common, but the platitude that both of them fall under a disjunctive description of the form “hallucinating O or perceiving O”.

Many philosophers are critical of disjunctivism, one of the main alleged flaws they identify being that there is no explanation offered by disjunctivists of why we should reject the existence of a common factor to hallucination and perception – the main tenet of disjunctivism seems to be taken as a brute, unexplained fact. The other side of the coin is that accepting a common factor seems very intuitive – there is something that hallucination and perception share, if they are subjectively indistinguishable, namely phenomenal properties.

As a general conclusion, then, there is prima facie reason to accept the existence of a common factor whenever two mental states are subjectively indistinguishable.

In this paper I will offer an argument against this general conclusion, which, if accepted, can explain why it makes sense to believe in the disjunctive view of perception and hallucination.

The argument focuses on auditory perception, and the phenomenon under consideration is that of hearing versus hallucinating silence. First, based on the last chapter of Roy Sorensen’s latest book (Seeing Dark Things: The Philosophy of Shadows, Oxford University Press, 2008) I will argue that it does make sense to think that there is such a thing as hearing silence. However, unlike Sorensen, I will avoid committment to silence as such, and only argue that we can hear that there is silence, so reference to silence is made within the scope of a propositional attitude operator.

Second I will argue that if we can hear that there is silence, we can also hallucinate that there is silence. This second step is an instantiation of the general premise of the argument from hallucination stating the possibility of a hallucination that is subjectively indistinguishable from a veridical perception.

Third, I will compare hallucinating and hearing silence, on the one hand, with being (or becoming) deaf (or temporarily deaf), on the other, arguing that these two states have nothing in common, but they are nevertheless subjectively/phenomenally indistinguishable.

Fourth, I will consider an objection to the previous step, the reply to which will generate a dilemma for those who subscribe to any common factor view. The objection is that there is nothing phenomenal about deafness, but precisely the lack of any phenomenality, so it is unwarranted to talk about phenomenal indistinguishability between the state of deafness and that of hallucinating or hearing silence. My reply is that one needs a thick, reifying conception of phenomenality in order to block the argument at this third step, but that conception would beg the question against disjunctivism—it would be equivalent to a premise directly stating the existence of a common factor rather than basing it on the innocent idea of subjective indistinguishability. So the dilemma is that either one rejects the relevance of the deafness versus hearing (hallucinating) silence, in which case one has to simply assume a common factor at the outset, or otherwise argue from a premise based on a purely epistemic conception of subjective indistinguishability, in which case one has to face the challenge of the case I will have presented, which shows that two mental states can be of two radically fifferent kinds, and nevertheless be subjectively indistinguishable.

Finally, I will argue that, if the argument works, there is no reason why not to accept the possibility that  hallucinating silence has nothing in common as a mental state with hearing silence, though they are subjectively indistinguishable.

Then, on the assumption that hearing silence is just a particular case of hearing in general, and of perceiving in general, we can conclude that we are not justified in accepting the move from subjective indistinguishability to the committment to a common factor, the key premise in the argument from hallucination.