The Nature of Mental Process

Harvey Carr
University of Chicago

This paper proposes the somewhat unorthodox view that the mental functions with which psychology concerns itself are in reality psychophysical, and at times neural, activities and that psychology shall study and attempt to comprehend these functions in their entirety. The author adopted this conception of the nature of mental process several years ago and is convinced from his teaching experience that such a mode of treatment possesses certain distinct advantages.

The conception may be contrasted with the more orthodox  'subjective' view which postulates psychophysical parallelism but which confines its efforts exclusively to a comprehension of the conscious or subjective aspect of these psychophysical events. Such a psychology studies color, sound, taste, and pain as experiential results but contends that the neural correlates of these sensory experiences belong to the domain of physiology. An emotion as a psychological phenomenon is described and defined in terms of sensational and affective processes subjectively regarded; the neural events involved in an emotion are relegated to the domain of physiology. The acts of memory, imagination, reasoning and will in so far as psychology is concerned with them consist merely of those aspects which can be immediately experienced; the neural events involved in the acts are quite important but their consideration involves a trespass into domains rightfully belonging to another science. Psychology thus deals exclusively with the purely conscious or psychic as opposed' to the nervous and material. Psychology is differentiated

( 181) from the material sciences in virtue of a peculiar subject matter and a peculiar method of apprehending its data.

Our conception also accepts psychophysical parallelism as a working hypothesis; it contends that psychology shall study psychophysical processes in their entirety, and that it shall include within its domain activities which lie outside the field of consciousness. Psychology will study emotions, and acts of reasoning, memory and will, but it will define and envisage these acts as psychophysical processes, and attempt to comprehend the neural events involved as well as those aspects immediately experienced.

The conception allows a division of the field of organic functions between the sciences of biology, physiology and psychology along natural lines of cleavage based upon differences of interest, training and technical procedure. Irrespective of definitions, psychology has been concerned with an ultimate comprehension of those operations by which an organism in virtue of its previous experience is enabled to adapt itself to a complex and variable environment. Physiology and biology have been interested in other types of functional activity-different in character, evolutionary history, and biological significance. The three sciences represent distinctions which appeal to radically different types of human motive and scientific interest, and which necessitate different sorts of training and technical equipment. This paper is not concerned with the formulation of an exact definition delimiting the boundaries of the three sciences.

The conception is unorthodox only in relation to prevailing definitions of psychology. To my mind it is essentially in harmony with the dominant point of view of the science, and it is not wholly inconsistent with much of current practice. Sciences have a way of developing and outgrowing their definitions. Practice and attainment often fail to square with theory and definition. The subjective conception of the nature of mental process (mental as opposed to material) originated from philosophical interests at a time when a dualistic conception of the human organism prevailed. At present the prevailing point of view in the science is biological,

( 183) ---a view which emphasizes the essentially unitary character of the human organism. The science is interested in certain modes of adjustment, and any adequate understanding of these processes of adjustment must necessitate a comprehension of the acts in their entirety. A division of any act of adjustment into its material and conscious aspects with the consequent treatment of but one component certainly gives a very inadequate comprehension of the phenomenon in question, and introduces a distinction which is not only without value, but which is likely to involve the student in many distracting perplexities. Our proposition, however, will necessitate no radical changes in much of current modes of procedure. As a matter of fact, many psychologies treat mental operations as psychophysical processes with only occasional lapses into a consistency with their subjective definitions of the science. It is our definitions that need revision, a revision in harmony with current tendencies and ideals.

The conception allows of a matter of fact treatment of the cause and effect relations in mental activity. One can assert that behavior is influenced by previous acts of memory or will and mean exactly what we say and what the unsophisticated mind understands by the statement. Psychologists will not be compelled to add for the benefit of the sophisticated qualifying phrases to the effect that although they asserted a causal influence of a mental act, yet they really did not mean it, but were forced to employ such statements by certain inadequacies of language. Any conception which allows of al natural and matter of fact treatment of the causal category in mental operations is at least deserving of respect. The new definition of the mental will permit a restatement and a solution of the mind-body problem more in accordance with common sense. Interactionism is logically possible; in accordance with popular belief we may say that our mind is influenced by bodily conditions and that our mind is also an effective influence upon bodily activities, for mind and body have been so conceived and defined in relation to each other that such statements are no longer logically or factually impossible. With our definition the distinction of mind and body is merely a distinction of two systems of organic function.

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Our definition will include within the domain of psychology the non-conscious components of mental life. I refer to such phenomena as retention, memory disintegration, conflict of impulses, Aufgabe, unconscious motivation, the concept of habit, and the wealth of subterranean activities brought to notice by the investigations of abnormal psychology. The subjective psychologies have assumed several attitudes toward these phenomena. Some are logically consistent with their presuppositions and attempt to ignore such intruders. Others admit the significance of these data for their purposes, but consistently remind their readers that after all these phenomena really belong to the domain of physiology. Others include these events within the domain of their science, but feel compelled by motives of consistency to impose upon these processes some sort of a 'conscious label.' Witness such terms as unconscious, subconscious, co-conscious, psychical dispositions, etc. These are not merely negative terms, equivalent to neural; they have a positive significance. Since these activities have a mental significance and since the mental must also be conscious, these acts must be conceived in such a way as to possess certain positive characteristics of conscious process. For my part, I prefer the remaining possible mode of procedure, viz., to revise my definition of the nature of mental process in such a way as to include such data.

The subjective conception of mental process as something immaterial constitutes an inadequate tool for the physician in his attempt to comprehend the nature of the mental, or functional disorders. Watson, in a recent article,[1] has, asserted his inability to understand the medical concept of mental disease. He cites a case which was diagnosed as being  'purely mental,' and which was described and defined wholly in conscious terms. Watson gives the impression that the physician was of the opinion that this disorder could not in any manner be stated in neural terms, that it was a disorder exclusively on the conscious plane without neural counterpart. Such a conception of the nature of the so-called mental diseases is of course foreign to current psychological

( 185) doctrines, and I doubt very much that such a view is universally prevalent in the medical profession. I am willing to admit that this and similar crude and preposterous conceptions are to be met with, but, unlike Watts, I am inclined to place the blame for this unfortunate state of affairs upon psychology rather than upon medicine. Medicine has merely adopted current conceptions. Psychology must be held responsible for the fact that better and more adequate conceptions were not available. Given a conception of mind as something non-nervous and non-material, crude notions of the nature of a mental disease must result. The mental will be distinguished from other diseases in terms of immaterial vs. material instead of functional vs. organic. The conception needlessly introduces into the discussion of mental disease and its treatment the old philosophical question of the relation of mind and body stated again in terms of the conscious vs. the physiological, or neural. Certainly the injection of such philosophical questions in discussions of the treatment of mental disease adds nothing of any positive value, introduces a perplexing distraction, and to my mind is wholly unnecessary. The old philosophical problem vanishes at once if we start out with the assumption that the disordered mental functions are in reality psychophysical events.

The psychophysical conception of mental process offers a mediating point of contact for the two extremes of subjectivism and behaviorism. Such a view permits the widest latitude as to methods of approach; it permits mental processes to be studied from the standpoint of immediate experience, of objective observation, or of clinical data. This suggestion of a common ground for the subjectivists and the objectivists, I am well aware, will evoke no approval from either of the warring camps. This phase of the argument is designed exclusively for the benefit of the neutrals. Our program will differ from that of the subjectivists in allowing an objective mode of approach to the problems of psychology; it will differ from behaviorism in two respects: it admits that the study of conscious data has given us much useful knowledge of the nature of mental operations and that further progress is

( 186) possible in the future. Behaviorism as defined logically includes the whole field of organic function. Psychology should be content with a more modest program and make a more reasonable division of the field of functional activity among the sciences of psychology, biology, and physiology.

The conception will modify our attitude toward the purposes and methods of comparative psychology. The subjectivist to be consistent must define the object of comparative psychology as a reconstruction of the inner life of an animal. Such a program appeals to some minds; to other minds it is repellent. The latter are impressed with the insuperable difficulties and limitations of the interpretative process, and are inclined to regard any results achieved as somewhat futile even if logically valid. Our conception makes possible for those who prefer it a purely objective or behavioristic science of comparative psychology, and yet permits others to reconstruct the conscious life of organisms if they so desire.

An exclusively subjective psychology is prone to meet certain needless difficulties in its presentation. The psychological discussion of a mental-event is usually followed by an explanation in terms of neural mechanisms which are labelled physiological. The psychological process viewed by itself impresses the mind of the student as a peculiarly inert and unimportant thing. When the neural mechanism is now added, the process takes on life and significance; mental processes can now do things and be effective instruments of organic adjustment. Moreover, the neural chain of events is, by hypothesis, more complete than the conscious aspect for not all neural events are represented in consciousness. It is small wonder that many students decide that they must look to physiology for any complete and real explanation of mental life. This sceptical attitude of the student toward psychology is not wholly unjustified, nor is it confined entirely to immature students; as a matter of fact this attitude toward our science is quite prevalent among the physiologists. I do not contend that it is impossible to meet such a position in a satisfactory manner; the significant point is that this attitude of scepticism is wholly unnecessary and exceedingly

( 187) detrimental. No science can afford to be placed in a defensive and apologetic position. The dual presentation further raises such distracting questions as the relative values of the neural and conscious components in an act of adjustment, their causal interrelations, and the necessity for a double treatment of mental events. All these are valid problems but they are philosophical in character and have no place in an empirical, matter of fact, science. Psychology , generally recognizes the philosophical character of these questions and their tendency to distract the mind of the student from the main task at hand, and the usual method of attempting to ignore them is by the adoption of parallelism as a working principle. To my mind this method fails utterly to achieve its purpose. Such philosophical questions must necessarily obtrude with a dualistic mode of presentation; in fact this method was developed at a time when psychology was studied primarily as an introduction to philosophical problems, and a better method for this purpose would be hard to devise. These difficulties are at least minimized if not eliminated by adopting the conception of this paper. Parallelism is adopted as a working hypothesis in a matter of fact way without calling the student's attention to it. The total activity is made the object of study; the dichotomy involved is not one of process, but one of method of approach or apprehension.

In conclusion we may say that there are no fixed and immutable boundary lines between sciences. Any science includes within its domain whatever is pertinent to its primary interest. If mental acts are means of organic adjustment, then these acts must be conceived and studied as such devices. If neural events are essential parts of the act, the conception of the mental must be broadened so as to include them.' There is no a priori necessity for defining the mental in nonmaterial terms, except habit and the force of tradition. The concept of the mental must be adapted to further the primary task of psychology as it is now conceived.


  1. "Behavior and the Concept of Mental Disease,' J. of Phil., Psychol., Etc., 1916, 13, 589.

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