Do we still need phenomenal consciousness? Comment on Block.

In a recent Opinion paper in TiCS, Ned Block [1] confronts the recent empirical and theoretical challenges to his distinction between two forms of consciousness (i.e. rich ‘phenomenal’ vs sparse ‘access’). Although we value his attitude of facing these issues, we still believe that the proposed ‘unaccessed phenomenal consciousness’, which is the cornerstone of this theoretical proposal, remains unfalsifiable and can be accounted for by other, more parsimonious, explanations. Block argues that the information prior to conscious access (e.g. letters prior to the cue in Sperling experiments) is phenomenally conscious. We have argued in previous work for the impossibility of probing the nature of these so-called ‘phenomenal’ contents without having subjects relying on some form of access to describe their experience [2,3]. As this would necessarily change the status of these contents, it renders impossible addressing whether they were of a phenomenal or unconscious nature prior to access [4–6]. Thus, an ‘observer effect’ might potentially render the whole issue immune to scientific investigation [7]. In his recent article [1], Block proposes a new strategy that consists of relying on measures of capacity as indirect evidence for phenomenal consciousness. According to this proposal, rich phenomenal consciousness translates to high capacity, as opposed to the scarce capacity of conscious access. However, Block omits the fact that capacity is a measure of informational availability, regardless of consciousness. As such, capacity may well reflect the amount of information that is unconsciously processed and that can potentially influence the cognitive system. We contend that any evidence for phenomenal consciousness, whether it is of a functional or neural type, can be reinterpreted as reflecting either partial awareness (when subjects express the feeling of being able to see more than they can report) or unconscious processing (when subjects are denying any form of awareness but some supposedly indirect marker of consciousness is observed). Block relies on a view of conscious access that is too restrictive. Yet, it is possible to reframe the issue of dissociable forms of consciousness into dissociable levels of conscious access. We recently proposed that an observer’s