How Can an Empirically Unobservable Process Have Physical Substrata?
If the above modification of the knowledge argument entails that phenomenal consciousness is not identical with anything empirically observable, it also entails that consciousness must be a process or aspect of a process that appropriates the empirically observable physiological substrata needed for its maintenance, growth, and reproduction. This further conclusion follows from the process of elimination; every other theory of the mind-body relation would imply untenable conclusions in light of the in-principle empirical unobservability of consciousness. I.e., psychophysical identity and epiphenomenalism imply that consciousness should be empirically observable, whereas dualism and interactionism of the Popper and Eccles (1977) variety (the claim that conscious and physical events causally interact, but that neither necessarily requires the other as its underpinnings) both imply that consciousness is a non-physical entity or event, requiring no physical substratum. Each of these implic
