ex Cambridge, Caltech & Cern
Journal of Consciousness Studies, 6, No. 1, 1999, pp. 70-90
The article proposes that cognition is supported by a 3D model of local space stored in Bose-Einstein condensates, which couple to neurons in the thalamus. This structure is also suggested to be the basis of consciousness. This is seen as likely to be favoured by evolution as an efficient means of storing data as well as being consistent with the properties of consciousness.
The author argues that neuroscience has so far only uncovered 2D maps in the brain, and that it would be much more economical for the brain to have evolved a 3D map. Against this, it could be argued that much of the lay out of the brain is not very economical, with vision processed at the back of the brain, and the right side of the body handled by the left side of the brain and visa versa. In fact, the lay out seems to be positively aimed at maximising the length of nerve tracts needed. In fact, it has been argued that this might be a way of extending quantum coherent structures over a large area of information processing.
The author suggests that there is nothing implausible with the idea that neurons could couple with a wave, as this is exactly what they do in the retina, where they couple with light waves. He reminds us that neurons can couple to signals at very low intensities, and this might extend to systems that have not yet been detected.
He also points out that given the known information capacity of neurons, it is hard to work how they perform some functions as fast as they in fact do. This ties in somewhat with those who argue for quantum computing in the brain, on the grounds that no classical computer could handle the amount of processing needed to achieve basic perception of objects within a reasonable time. He also points out that, as it stands, neuroscience does not give us a clear distinction between conscious and unconscious activity.
The article also suggests that there is a control mechanism to direct the attention of the proposed 3D model. There is stated to be evidence in favour of thalamic reticular nucleus performing such as role (Newman, 1995 & 1996) (1&2). The thalamic reticular could be directed by inputs from the rear of the cortex, where objects and their position are recognised, and from the midbrain reticular which orientates to new stimuli and the prefrontal. P The article recalls the past theories of Bose-Einstein condensates or other quantum coherence in the brain, starting with Fröhlich (1968) (3), who proposed a metabolic energy pumping mechanism to sustain a condensate, and also Umezawa (1993) (4), Vitiello (1995) (5), Hameroff (1994) (6) and Gershenfeld & Chuang (1997) (7). The author admits that rapid decoherence in the brain is a problem for all these theories, but does not go into how it might be prevented. P Marshall (1989) (8) appeared to advance the view that the Bose-Einstein condensates were themselves conscious, and would as such experience the local 3D map stored in the thalamus. This is therefore seen as the basis of consciousness and it does not require a further observer behind or beyond it. The 3D map and the single quantum state condensate theory of consciousness appears also to solve the binding problem, explaining how it is all brought together in one place.
The article also points to evidence (Bogen, 1995) (9) that damage to the thalamus and particularly the Intra-Laminar Nuclei, interrupts consciousness, which is not the case with most other areas of the brain. The author feels that the theory bridges the explanatory gap found in consciousness theories based on classical physics. However, he feels that the theory nonetheless has something in common with some of the more popular mainstream theories of consciousness. The Global Workspace theory of Baars & Newmann (10 & 11), where the workspace broadcasts the results of computations to different neural modules is seen a s similar to the proposed 3D mastermap. Damasio’s theory (12) involving somatosensory data and a body model in consciousness and cognition is seen as having similarities to the body’s role in the 3D mastermap.
However, it is pointed out that all these theories leave an explanatory gap in that all the systems described could function without consciousness. Churchland (1995) (13) has tries to bridge this gap, with identity theory, which tries to say that neural activity is consciousness in the same way that molecular motion is heat. The author feels that the identity theory does not account for most of the properties of consciousness. He also points out that identity theory does not provide an explanation for the distinction between conscious and unconscious activity in the brain. A century of increasingly detailed examination of the brain and neurons has not thrown up a plausible distinction between conscious and unconscious areas or functions, and is not apparent in any detailed study of a particular area of neurons.
A further criticism might be that it does not provide the detailed cause and effect sequence that we demand from science. Thus when we say that heat is molecular motion, we also know from current science that the sufficiently rapid motion of molecules changes the bonds between particles in such a way that phase changes between solid, liquid and gas or chemical changes such as burning occur. It is not just a correlation between molecule motion and heat, there is also an observable detailed process. There are all sorts of correlations between neural activity and consciousness but existing mainstream neuroscience has no detailed mechanisms such as breaking or forming of bonds between molecules that shows how consciousness arises.
It is pointed out that quantum theories of consciousness fall into two groups, collapse theories such as those of Stapp (14) and Penrose/Hameroff (15), where consciousness is related to the collapse of the wave function, and state theories, such as the one discussed here, where consciousness resides in a particular quantum state. Worden claims that decoherence is a much greater problem for collapse theories than for state theories.
The main problem with this theory is that it offers no particular reason why a quantum condensate should be conscious. In this it is no different from mainstream theories based on classical physics, going right back to Descartes, which simply decree that a particular brain feature or process is conscious or consciousness. The Penrose/Hameroff model, which also posits condensates in the brain links their collapse to the fundamental space-time geometry which provides the non-computable element in human thinking. One may not like the various assumptions and speculations involved in the model, but is does provide a reason why consciousness should arise at this level.