Perception,introspective indiscriminability and the common factor principle

Conjunctive philosophical theories of visual experience accept the common kind principle,according to which perceptions and their introspectively indiscriminable hallucinatory counterparts should be considered as mental states or events of the same kind. In this paper I criticize two strategies that allegedly entail the adoption of the common kind principle. First,I will take into account some causal considerations linked to vision science that might lead us to endorse the local supervenience of the phenomenal character and the sameness of experiential kind. Secondly,I discuss whether introspective indiscriminability is a sufficient criterion for the identity of phenomenal character and experiential kind. I point out that these strategies do not conclusively motivate the adoption of the common kind principle as it is often assumed.