The Intermediaries of the Mind
Written by Dr. Nash Popovic
We will discuss in this part three mental faculties that enable experience and information: perception, memory and learning. We will also address dreaming as an example of auto-generating processes. We hope to demonstrate that these faculties can be better understood if the roles of both material and non-material aspects are recognised.
Some issues related to perception have been already addressed. The focus here will be only on one essential question: how are nerve signals turned into perception of the world? Neuroscience and other related disciplines have not provided a satisfactory answer and are unlikely to do so as long as they operate within the presently dominant paradigm. More than forty years on and Eccles’ comment (Popper and Eccles, 1977, p.225) is still relevant:
There is a general tendency to overplay the scientific knowledge of the brain, which regretfully, also is done by many brain scientists and scientific writers. We are told that the brain “sees” lines, angles, edges, and simple geometrical forms and that therefore we will soon be able to explain how a whole picture is “seen” as a composite of this elemental “seeing”. But this statement is misleading. All that is known to happen in the brain is that neurones of the visual cortex are caused to fire trains of impulses in response to some specific visual input. Neurons responding to various complications of this specific visual input are identified but there is no scientific evidence concerning how these feature-detection neurones can be subjected to the immense synthetic mechanism that leads to a brain process that is “identical” with the perceived picture.
It is known that retinal processing is involved in detecting intensity and wavelength contrast; early cortical areas in the brain are involved in orientation, curvature, spatial frequencies and movement; and high visual areas (in the parietal and temporal lobe) process sensations about the spatial relationships and the identity of visual objects. This, however, is not sufficient. As far back as 1938, famous neurophysiologist and Nobel laureate, Charles Sherrington, writes:
A star we perceive. The energy scheme deals with it, describes the passing of radiation thence into the eye, the little light-image of it formed at the bottom of the eye, the ensuing photo-chemical action of the retina, the trains of action potentials travelling along the nerve to the brain, the further electrical disturbance in the brain, the action-potentials streaming thence to the muscles of eye-balls and of the pupil, the contraction of them sharpening under the light-image and placing the seeing part of the retina under it. The ‘seeing’? That is where the energy-scheme forsakes us. It tell us nothing of any ‘seeing’. Much, but not that. (1940, p. 248)