There has been much discussion of what a scientific theory of consciousness would look like, and even whether such a theory is possible. Some common misunderstandings of the nature of theories (e.g., in the physical sciences) have confused the discussion of theories concerning consciousness. Theories in the physical sciences establish hierarchies of descriptions that relate high-level descriptions of macro-level phenomena to detailed-level descriptions at a micro level. Detailed descriptions are usually more accurate but information-dense and therefore often beyond human comprehensibility (unless limited to tiny segments of a macrolevel phenomenon). High-level descriptions are usually much less information-dense but more approximate. The ability to map between levels of description, and in particular the understanding of when a shift from a higher-level to a more detailed description is needed to achieve a desired degree of accuracy, is fundamental to an effective theory in any field. The form of such a theory of consciousness is sketched, and the limitations of some alternative approaches described.
IntroductionThere are a range of possible approaches aimed at understanding consciousness. At one extreme, there has been debate over whether a scientific theory of consciousness is possible in principle [e.g. Chalmers 1995]. Another type of approach has been the creation of models that describe cognitive operations regarded as being conscious, but with limited consideration for how physiology could support the processes required by the model. Computer implementations of some of these models have been attempted [e.g. Franklin et al 1999, Sun 1999]. Yet another approach has been to look for physiological activity that discriminates between conscious and unconscious states, the so-called "neural correlates of consciousness" [e.g. Rees et al, 2002, Crick et al 1998]. Yet another approach has been to claim that understanding of consciousness is only possible with reference to quantum mechanics [Penrose 1994]. Furthermore, there have been extensive debates over what phenomena should actually be labeled "conscious" [e.g. Block 1995]. The end result has been considerable metatheoretical confusion.For several centuries, the physical sciences have been regarded as the paradigm for valid scientific theories. We believe that much of the confusion over scientific understanding of consciousness derives from misunderstanding of what theories in the physical sciences actually deliver, and once these misunderstandings are cleared away, the form which a theory of consciousness must take becomes clearer. There are some good questions about whether a scientific theory of consciousness is possible, but these questions are in fact more empirical than philosophical, and relate to whether the brain is organized in such a way that understanding can occur within the limits of human information handling capabilities.There are some significant similarities between theories in the physical sciences and the theoretical techniques by whi...