Brain and Consciousness: A Discussion About the Function of the Brain

BRAIN AND CONSCIOUSNESS: A DISCUSSION ABOUT THE FUNCTION OF THE BRAIN* W. R. HESS and H. FISCHERf Dr. Hess to Dr. Fischer I should like to add a few thoughts to our discussion. At the time when we both were members of the medical faculty, your opinion struck me as concurring in many ways with mine. It soon became evident, however, that in questions of philosophy of life we differ considerably. This refers to the so-called ultimate questions which every scientist is bound to face sooner or later and which may even cause him conflicts of conscience. I shall try to point out where our respective opinions diverge. You are relying on ancient traditions, whereas I have been brought up in the belief of, and am working with, the laws of natural science. In other words, my opinions are based on observation and experience. In particular , I have always respected the limits set by the organization of the brain, and I hold that it is basically impossible to come to valid conceptions about matters which are inaccessible to our means of perception. Here is an example. For me, the contents of visual perception are represented by the excitation of some retinal elements and their propagation through fiber tracts to the occipital neuron populations. The fiber paths can be seen under the microscope, the propagation of the excitation can be followed , and their arrival at the occipital area determined by electrical recording . The transition from neuronal activity to the subjective experience is not, however, accessible to rational understanding. It is, nevertheless , a reality. You, for example, suggest that language is an objective replica of a feeling or of a train of thought. To my mind, the representation is merely formal and is comparable to a photograph of a landscape with mountains, waterfalls, lakes, flowers, etc., in short, of those features * Editor's note,—Drs. W. R. Hess and H. Fischer have carried on a friendly debate on the functions of the brain for some years. They have not come to agree on all points. Each desires to publish his present position on brain function.—D. J. I. t Professor Hess died August 12, 1973. His address was 6612 Ascona, via Gabbio 6, Zurich, Switzerland. Professor Hans Fischer, Witellikerstrasse 60, 8702 Zollikon, Zurich, Switzerland. Perspectives in Biology and Medicine · Autumn 1973 | 109 of an object displayed in space which are apt to be represented in the photograph. I refer to the short monograph Psychologie in biologischer Sicht [1, 2] and to an atlas [3, pp. 66-67] which show how I arrived at the experimental basis of our subject. Illustrations 201 and 203 [3] should be studied. I consider the evidence adequate to show that the electrical stimulation applied in a defined area of the hypothalamus is able to produce behavior which closely resembles that which under natural circumstances accompanies rage and aggressiveness. The question arises here as to whether this behavior is the concomitant of subjective experience. If one considers the further information that a cat in this situation turns toward the experimenter and purposively hits his hand, or even prepares to jump at him, one cannot but assume that the appropriate subjective experience is integrated into the whole purposeful behavior. It is likely to be substantially the same as in the case of a dog approaching a cat, or of a man engaging in a fight with a counterpart. When cat or man fights back and experiences the corresponding feelings, our interpretation reaches the critical point. The excitation of defined cerebral areas is a fact; the neurophysiological organization of behavior is accessible to rational understanding . How the electrical excitation of nervous matter is converted into subjective experience, on the other hand, is an open question. You hold the opinion that the answer must come from philosophical thought. In my own view the gap in our knowledge must be admitted and explained by the fact that our brain is not organized to analyze its own mechanisms, although it is able to assess certain results of its activity. In other words, its organization is aimed at only a limited number of performances out of all possible performances. Let us take the...