Ned Block has provided a beautiful argument against Ground Representationism—the position that for each phenomenal feature there is a representational feature that accounts for it. At its core is the notion of “phenomenal precision”: if we accept it, it seems that the degree of phenomenal precision of a percept changes differently to its degree of representational precision. Thus, there is no representational feature that accounts for this change in phenomenality—and Ground Representationism is false.
I have suggested a way of estimating phenomenal precision based on the assumption that parts of perceptual wholes can share characters independently of where they occur in the perceptual whole, and on the notion of a just noticable difference as a lower bound of p–precision, which is inspired by Block’s Phenomenal Precision Principle. Understood in this way, the argument shows what it is supposed to show: Ground Representationism is false.
But a deeper look at the notion of phenomenal precision suggests some tension with Block’s other work or with introspective evidence, which Block takes seriously. In order to allow for variation in the degree of precision, we have to accept that some of our experiences are not concrete, but solely generic. Such “solely generic phenomenology”, however, is a position mainly held by opponents to Block’s Access- vs. Phenomenal Consciousness-distinction. Without accepting solely generic phenomenology, however, phenomenal precision seems either trivial (there is no variation) or contradictory (a percept can simultaneously have various degrees of p–precision). So the argument against Ground Representationism either hinges on a trivial or self-contradictory notion, or it is incompatible with Block’s positions elsewhere. Patching this problem by allowing a limited range of characters outside our attention is again at odds with Block’s other writing and with introspective evidence.
What is needed is a better understanding of phenomenal precision. What is it? How can we estimate it? I have suggested some possible ways to answer these questions, but all that I could come up with seems at odds with what Block has in mind. This certainly does not mean that there cannot be a suitable version of phenomenal precision that avoids these pitfalls—I am just unable to find it, and all that I can construct somehow goes against Block. I hope that Block has some ace up his sleeve, because the notion of phenomenal precision appears too fruitful to be abandoned too hastily.
Acknowledgements
I am very grateful to Frank Jäkel for help and discussion concerning the psychophysical side of this article, and to Thomas Metzinger as well as two anonymous reviewers for their supportive comments and criticism.