Reflections on the interaction of the mind and brain
Introduction
The generally held assumption that mind and brain can interact indicates from the outset that two different phenomenological entities exist. Conscious mind can only be regarded as a subjective experience, which is accessible only to the individual who has it. Thus, it can only be studied by reports given by the subject her/himself. It cannot be observed or studied by an external observer with any type of physical device. In this sense, subjective experience (the conscious mind) appears to be a non-physical phenomenon. Indeed, it was recognized as far back as Gottfried Leibniz (1646–1716) that if one could look into the brain and observe all its nerve cell activities, one would not see anything to indicate the existence of a conscious mind. In contrast, Pierre-Simone Marquis de Laplace (1749–1827) believed that if the nature of the molecules and structures in any system were known, one could describe and predict all of its behaviors (Laplace, 1914). Laplace was thus the ultimate materialist! Even if one believes Laplace's views, they could never be tested, of course, because impossibly large numbers of elements are involved. It is also necessary to accommodate the unpredictable effects of random events (chaos theory) and the uncertainty principle of Werner Heisenberg (1901–1976). Similar untestabilities apply to any materialist theory of mind.
How do the materialist's molecules and structures give rise to subjective experience? Simply stating that some (unknown) configuration of neuronal activities equals consciousness (subjective experience) avoids or begs the problem.
Section snippets
Contributions of John Eccles to the problem of mind–brain interactions
At this point it is relevant to consider the contributions of Sir John Carew Eccles (1903–1997) to the problem of mind–brain interactions. “Jack” (to his colleagues) was a remarkable contributor even to a field far removed from his superb experimental discoveries on the mechanisms of synaptic transmission and functional controls within the central nervous system (see the reports of Brownstone, 2006, Burke, 2006, Willis, 2006, Hultborn, 2006, Wolpaw and Carp, 2006, Andersen, 2006, Ito, 2006,
The cerebral mental field (CMF)
Hiroomi Umezawa and his followers proposed a mental field model, which they termed a “quantum field theory.” It was claimed by the authors that this theory is distinguishable from “quantum mechanics” (Umezawa, 1993). Their model is mostly mathematical, however, and it is not clear how it can be tested. In the interpretation of quantum theory by Nils Bohr (1885–1962), mind and matter are two aspects of one undivided process. David Böhm (1917–1992) adopted this idea (see Böhm and Factor, 1985).
Extracranial studies
In recent decades, brain imaging studies, including PET scans and MRI, have been numerous and significant. They can provide information on changes in blood flow in localized areas of the brain, as well as activity-dependent changes in specific metabolites. David Ingvar and his colleagues initiated direct study of blood flow patterns (for review, see Ingvar, 1999). In their initial experiments, changes in local blood flow were observed not only during voluntary acts but also when the subject
Concluding thoughts
The nature of the interaction between mind and brain is clearly difficult to understand, since it involves the production of non-physical subjective experiences by appropriate neuronal activities. If an experimental test of the CMF was to be carried out, like that described above, it might confirm or contradict the kind of alternatives possible for a mind–brain interaction. The eminent neuroscientist, Robert W. Doty, has remarked to me that he does not believe that a CMF test will produce a
Acknowledgements
For our experimental intracranial studies, I am indebted to the cooperative patients who underwent therapeutic neurosurgery and to my colleagues, Bertram Feinstein, W. Watson Alberts, Elwood (Bob) Wright Jr., and Curtis Gleason. I would also like to express my gratitude for the possibility to work with Eccles on cellular issues in Canberra, Australia (1956–1957) and his sustained interest in and support of my subsequent studies on the human brain. Re the latter, many leading neuroscientists
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