Requiem for the identity theory

This paper examines the impact that recent advances in clinical neurology, introspectionist psychology and neuroscience have upon the philosophical psychoneural Identity Theory. Topics covered include (i) the nature and properties of phenomenal consciousness based on a study of the 'basic' visual field, i.e. that obtained in the complete dark, the Ganzfeld, and during recovery from occipital lobe injuries; (ii) the nature of the 'body-image' of neurology and its relation to the physical body; (iii) Descartes' error in choosing extension in space as the criterion for distinguishing the physical and the mental; (iv) the technical distinction between sensing and perceiving; (v) why phenomenal Direct Realism is incorrect whereas epistemic DR and the representative theory are correct; (vi) the ontological and topological status of phenomenal space and physical space. This leads to considerations of the current 'binding problems' in neuroscience; the role of the brain mechanisms that construct the sensory fields of phenomenal consciousness; the 'homunculus' fallacy; the key difference between epistemic and non-epistemic perception as revealed by brain injury studies; and how the brain codes information, contrasting topological and vectorial coding, with particular reference to the binding problem. My conclusion is that the Identity Theory is incompatible with the scientific evidence from an integrated approach to modern introspectionist psychology, clinical neurology, and neuroscience. However, Cartesian Dualism is even more incompatible with the evidence. This leaves only two viable theories. The first is Bohr's theory of brain-consciousness complementarity. The second is the Broad-Price-Smythies theory of extension, which is a topological theory of the relation between phenomenal space and physical space.