Ned Block

Neuroscientists continue to search for 'the' neural correlate of consciousness (NCC). In this article, I argue that a framework in which there are at least two distinct NCCs is increasingly making more sense of empirical results than one in which there is a single NCC. I outline the distinction between phenomenal NCC and access NCC, and show how they can be distinguished by experimental approaches, in particular signal- detection theory approaches. Recent findings in cognitive neuroscience provide an empirical case for two different NCCs.

This book argues that there is a joint in nature between seeing and thinking, perception, and cognition. Perception is constitutively iconic, nonconceptual, and nonpropositional, whereas cognition does not have these properties constitutively. The book does not appeal to “intuitions,” as is common in philosophy, but to empirical evidence, including experiments in neuroscience and psychology. The book argues that cognition affects perception, i.e., that perception is cognitively penetrable, but that this does not impugn the joint in nature. A key part of the argument is that we perceive not only low-level properties like colors, shapes, and textures but also high-level properties such as faces and causation. Along the way, the book explains the difference between perception and perceptual memory, the differences between format and content, and whether perception is probabilistic despite our lack of awareness of probabilistic properties. The book argues for perceptual categories that are not concepts, that perception need not be singular, that perceptual attribution and perceptual discrimination are equally fundamental, and that basic features of the mind known as “core cognition” are not a third category in between perception and cognition. The chapter on consciousness leverages these results to argue against some of the most widely accepted theories of consciousness. Although only one chapter is about consciousness, much of the rest of the book repurposes work on consciousness to isolate the scientific basis of perception.