The five mysteries of the mind, and their consequences

Alkmaion’s discovery that brain creates mind: A revolution in human knowledge comparable to that of Copernicus and of Darwin

Without special examination the brain offers no clue that it is the organ of the mind. From the dawn of time man thus either ignored the problem as to the source of thought, or attributed it to a variety of anatomical structures, usually the heart. The brain held no place in such intuitions, and in most languages it is analogized to bone marrow. Furthermore, nothing in early medical systems claimed any intellectual capacity for the brain; and the Egyptians, so fastidious in care for their afterlife, heedlessly discarded the brain in funerary practice. It was thus a unique event in world history when Alkmaion of Kroton (Alcmaeon, ca. 500 bc), based on anatomical evidence, proposed that the brain was essential for perception. Although no writings of Alkmaion survived, it was probably via a fortuitous linkage that his idea of the mental primacy of the brain was transmitted to, and preserved within, the teachings of the Hippocratic school. Nothing, of course, was secure as to mechanism, two millennia unfolding until the search for mind passed from the ventricles to the cerebral cortex. Nonetheless, Alkmaion was the beginning, and the ensuing understanding that he initiated is still transforming humanity's perception of the natural world, and their place within it.

Reflections on the interaction of the mind and brain

Problems associated with the topic of the mind-brain interaction are reviewed and analyzed. If there is an interaction, then the "mind" and "brain" are independent variables; the mind represents subjective experience and is therefore a non-physical phenomenon. This fact led to the need for a field theory, termed here the "cerebral mental field" (CMF). By definition, the CMF is a system property produced by the appropriate activities of billions of neurons. An experimental test of this theory is possible and a test design is presented. The most direct experimental evidence has been obtained by use of intracranial stimulating and recording electrodes. Important information has also been developed, however, with extracranial imaging techniques. These can be very fast (in ms), but the cerebral neuronal events that produce changes in physiological properties require a time delay for their processing. A number of surprising time factors affecting the appearance of a subjective somatosensory experience are described, and their wider implications are discussed. Among these is a delay (up to 0.5 s) in the generation of a sensory awareness. Thus, unconscious cerebral processes precede a subjective sensory experience. If this can be generalized to all kinds of subjective experiences, it would mean that all mental events begin unconsciously and not just those that never become conscious. In spite of the delay for a sensory experience, subjectively there appears to be no delay. Evidence was developed to demonstrate that this phenomenon depends on an antedating of the delayed experience. There is a subjective referral backward in time to coincide with the time of the primary cortical response to the earliest arriving sensory signal. The subjective referral in time is analogous to the well-known subjective referral in space. In conclusion, features of the CMF can be correlated with brain events, even though the CMF is non-physical, by study of subjective reports from the human subject.

Split-brain basics: relevance for the concept of one's other mind

Frontal and horizontal sections of the cerebrum make plain that with a few exceptions (pineal, pituitary) all structures are paired. Hemicerebrectomy has made clear that only one member of the hemispheric pair suffices to sustain the sentiments, emotions, memories, and intentions both conscious and unconscious that we call in the aggregate, mind. That the anatomical duality can sustain a duality of mentation is evident from not only the split-brain results in all species examined but also the results of appropriate testing of anatomically intact individuals. There is no physiological evidence for a plurality of mind beyond duality. Psychoanalytic views of mind can benefit from revision in the light of the split-brain studies. But such revisions seem slight compared with improvements needed in the views prevalent among most other psychologic and philosophic theorists.

My developing understanding of Roger Wolcott Sperry's philosophy

Reviewed are some of the dramatic experimental results and penetrating analyses characterizing the career of Roger Sperry. These require that we seriously consider his opinions regarding matters not yet testable, especially regarding the brain/mind relationships. His opinions include first, that a worthwhile understanding of brain function requires a biological explanation of consciousness; second, that mental properties described by him as "overall pattern effects in brain dynamics" can govern neuronal traffic at the cellular level by virtue of "mental forces'; and third, that further development of this outlook can provide a scientific basis for moral values. Discussion here is restricted to the first two of these points, urging that most criticisms of them arise largely from semantic confusions inherited from our past. Particular emphasis is placed on distinguishing mind from soul, thus totally separating the brain-onto-mind mapping problem from the nexus problem inherited from Descartes. Taken here is a physicalist position regarding mind, together with agnosticism regarding the nonmaterial.