A critical review of EEG and MEG markers of the neural correlates of consciousness (NCC) for visual, auditory, and tactile stimuli concludes that two prominent signals—the early, modality-specific visual and auditory awareness negativities (VAN and AAN) and the late, modality-independent P3b—are not equally valid NCC. More than twelve studies found the P3b absent despite conscious perception, ruling it out. No convincing evidence dissociates the awareness negativities from consciousness. Evidence for a tactile equivalent, the somatosensory awareness negativity (SAN), supports a generalized perceptual awareness negativity (PAN) correlated with perceptual consciousness, arising 120–200 ms after stimulus onset from sensory cortices. This PAN points to new research avenues.
Integrated information theory (IIT) shares with panpsychism the view that consciousness is an intrinsic, fundamental property of reality that is graded and present in small amounts in simple physical systems. However, IIT improves on panpsychism by clearly specifying which systems are conscious and which are not, thereby resolving panpsychism's combination problem, and by explaining why consciousness can be adaptive. The fundamental weakness of panpsychism and other -isms is that they fail to provide a sustained conceptual or empirical research program that generates novel insights or proposes new experiments. Without such a program, progress on the mind–body problem will not occur.
Integrated information theory (IIT) proposes that consciousness can be understood by starting from the essential properties of experience itself, such as its intrinsic existence, composition, information, integration, and exclusion. From these axioms, the theory derives physical requirements for a system to be conscious. IIT offers a principled account of both the quantity and quality of experience, and provides a calculus to determine whether a physical system is conscious. It explains clinical and laboratory findings, makes testable predictions, and suggests that consciousness is graded and common among biological organisms, including some simple systems. In contrast, it predicts that feed-forward networks and digital computers, even those simulating the human brain, would experience little to nothing.