The Sensory Order: An Inquiry into the Foundations of Theoretical Psychology

INTRODUCTION

by HEINRICH KLÜVER

IT has been said that a philosopher is a man who has a bad conscience whenever he hears the word philosophy. Nowadays psychologists no longer seem to develop feelings of guilt when encountering the word psychology. This state of affairs can certainly not be accounted for by assuming that the whole field of psychology has suddenly acquired the status of a ‘science’. In fact, scientific progress in psychology within the last generation according to some critics has been deplorable. A turn for the better, however, would not necessarily be achieved by eliminating all psychologists. There is no doubt that physiologists, neurologists, psychiatrists, anatomists, sociologists, biologists, and workers in other fields would keep psychology alive in one form or another if psychologists were to disappear from the contemporary scene. Investigators in various non-psychological fields are, in the pursuit of their inquiries, again and again forced to deal with psychological problems and even driven to consider problems of theoretical psychology. For example, about ten years or so ago, Sherrington felt compelled to consider the interrelations of neurophysiological and psychological phenomena and to devote several hundred pages in his Man on His Nature to an examination of problems of the ‘mind’.

Dr Hayek’s book, which represents an analysis of the sensory order in relation to problems of theoretical psychology, raises the question whether the time has not again come for psychologists to develop, at least occasionally, a bad conscience when hearing the word psychology. On the one hand, there seems to have been a decline in the quality and quantity of systematic endeavours in the field of theoretical psychology during the last decades; on the other hand, the multifarious activities of psychologists seem to make it more than ever necessary to find a common point of reference. As long as it is assumed, or as long as the illusion is to be kept alive, that the diverse activities of psychologists involve a common factor referrred to by the word psychology, the general conceptual framework of such a psychology must remain of fundamental interest. There is, of course, no lack of theorizing in modern psychology. It is one thing, however, to develop a theory based on the detailed experimental analysis of a particular problem; it is another thing to examine the conceptual tools of theoretical psychology itself. Even particular theories do not always escape the complexity of matters psychological. When G. E. Müller summarized his fifty years of efforts in the field of colour vision, it took him about 650 pages to present his theory of colour vision and he insisted that any simpler theory could be formulated only at the price of ignoring relevant facts. When it comes to systematic efforts in the field of theoretical psychology, it has become increasingly obvious in recent years that psychologists find their particular tasks (ranging from an analysis of ocular to an analysis of political movements and from investigations of the sexual behaviour of male army ants to that of human females) so all-absorbing, time-consuming and exacting that they rarely seem to do anything but increase the number of hastily conceived and irresponsible theories. In fact, nowadays, only a man like Dr Hayek who is sufficiently removed from the noisy market places of present-day psychology appears to have the necessary detachment and peace of mind for a systematic inquiry into the foundations of theoretical psychology.

It is fortunate indeed that Dr Hayek has chosen the sensory order as a basis for discussing problems of theoretical psychology. More than a century ago, in 1824, Flourens insisted that une anatomie sans physiologie serait une anatomie sans but. There is no doubt that an ‘anatomy without physiology’ as well as a ‘physiology without anatomy’ are still with us. Even at the present time, it is not difficult to find books on the ‘physiology’ of the nervous system which are in effect nothing but books on ‘anatomy’ containing elaborate physiological footnotes. The relations between physiology and anatomy acquire particular significance and complexity when it comes to the field of sensory physiology. If not the last, at least the last monumental attempt to cope with problems of the sensory order is to be found in J. von Kries’s General Sensory Physiology published in 1923. It was von Kries who explicitly stated what has been recognized by practically all investigators in this field, namely, that sensory physiology is different from all other fields of physiology and, in fact, from all other natural sciences in that its problems are intimately related to, if not identical with, certain problems of psychology, epistemology, and logic. In fact, sensory physiology and sensory psychology are to a great extent indistinguishable. The psychologist will remember that the duplicity theory of vision formulated by von Kries has stood the test of time longer than is generally the case with scientific theories and that Selig Hecht, only a few years ago, when performing energy measurements to determine the minimum energy necessary for vision, found values of the same order of magnitude as were found by von Kries more than forty years ago although von Kries did not even make energy measurements. Since Hecht considered it ‘astonishing to see the admirable way’ in which von Kries accomplished this task, he felt called upon to pay tribute to von Kries’s skill and care in the evaluation of absorptions, reflections, lens factors, and the like, which are necessary in determining the minimum energy. It cannot be said, therefore, that the man who insisted that problems of sensory physiology cannot be adequately treated without recourse to psychology, epistemology, and logic did not have the necessary ‘hard-boiled’ attitude in scientific matters; the converse is obviously true. Just why the sustained and disciplined thinking of a ‘hard-boiled’ professor of physiology in matters of sensory physiology should be dismissed as ‘mere’ philosophy by psychologists is a problem which clearly requires an analysis by a competent historian unless one assumes that the inability of most psychologists to handle logical and epistemological tools explains such a phenomenon. Such phenomena, unfortunately, have not been rare in the history of psychology. Ziehen, the neuroanatomist, psychiatrist, psychologist, and logician, who wrote a textbook of physiological psychology that went through numerous editions, also wrote an ‘epistemology on psychophysiological and physical basis’ in 1913. It is true that this book has a forbidding title and about 600 pages; but it is probably also true that no psychologist alive ever read all of its pages in the period between World War I and World War II. There is no doubt that a critical examination of the concepts of general sensory physiology in relation to psychology and other fields is a prerequisite for further progress in many physiological and psychological areas of investigation. Dr Hayek, who appears to be far too modest in evaluating his own competence in handling and elucidating sensory physiological and psychological concepts, is, therefore, performing a task urgently needed for further scientific progress.

Problems of the sensory order and the relations between physical and sensory phenomena have been of perennial interest not only to psychologists and physiologists, but also to mathematicians, logicians, and physicists. Recently they have even become of interest to communication engineers. As P. du Bois-Reymond once pointed out, all of us are enclosed ‘in the box of our perceptions’. There have always been some who think that it is possible to escape from this box and there have always been others who think that this is not possible. Ziehen, for instance, was of the opinion that we find everywhere identities, similarities, and differences in examining the ‘given’, i.e., the raw data furnished by experience or, to use his expression, the ‘gignomene’. A fundamental classificatory principle is thus part and parcel of the ‘gignomene’ themselves and constitutes an ultimate ‘unexplainable and indefinable fact’. It is of interest that von Kries, too, believed that the existence of similarities is an ultimate fact neither requiring nor permitting of an explanation. The view, however, that the real content of experience resisting any further analysis is to be found in sensory phenomena has always clashed with the view that the persistence of fixed functional relations between these phenomena constitutes the content of true reality.

In a brief space, it is impossible to outline even the essentials of Dr Hayek’s theory, but from a broad point of view his theory may be said to substantiate Goethe’s famous maxim ‘all that is factual is already theory’ for the field of sensory and other psychological phenomena. According to Dr Hayek, sensory perception must be regarded as an act of classification. What we perceive are never unique properties of individual objects, but always only properties which the objects have in common with other objects. Perception is thus always an interpretation, the placing of something into one or several classes of objects. The characteristic attributes of sensory qualities, or the classes into which different events are placed in the process of perception, are not attributes which are possessed by these events and which are in some manner ‘communicated’ to the mind; they consist entirely in the ‘differentiating’ responses of the organism by which the qualitative classification or order of these events is created; and it is contended that this classification is based on the connexions created in the nervous system by past ‘linkages.’ The qualities which we attribute to the experienced objects are, strictly speaking, not properties of objects at all, but a set of relations by which our nervous system classifies them. To put it differently, all we know about the world is of the nature of theories and all ‘experience’ can do is to change these theories. All sensory perception is necessarily ‘abstract’ in that it always selects certain aspects or features of a given situation. Every sensation, even the ‘purest,’ must therefore be regarded as an interpretation of an event in the light of the past experience of the individual or the species. Experience operates on physiological events and arranges them into a structure or order which becomes the basis of their ‘mental’ significance. In the course of ontogenetic or phylogenetic development, a system of connexions is formed which records the relative frequency with which different groups of internal and external stimuli have acted together on the organism. Each individual impulse or group of impulses on its occurrence evokes other impulses which correspond to stimuli which in the past have usually accompanied its occurrence. The primary impulse through its acquired connexions will set up a bundle of secondary impulses, a ‘following’ of the primary impulse. It is the total or partial identity of this ‘following’ which determines different forms of classification. The essential characteristic of the order of sensory qualities is that, within that order, each stimulus or group of stimuli does not possess a unique significance represented by particular responses, but that the stimuli are given different significance if they occur in combination with, or are evaluated in the light of, an infinite number of other stimuli which may originate from the external world or from the organism itself. A wide range of mental phenomena, such as discrimination, equivalence of stimuli, generalization, transfer, abstraction, and conceptual thought, may all be interpreted as different forms of the same process of classification which is operative in creating the sensory order. The fact that this classification is determined by the position (in a topological, not a spatial, sense) of the individual impulse or group of impulses in a complex structure of connexions, extending through a hierarchy of levels, has important consequences when it comes to considering the effects of physiological or anatomical changes.

These formulations of the author must suffice to characterize at least some aspects of the theory presented in his book. Investigators concerned with an analysis of the logical structure of natural sciences have insisted that the transition from concepts of ‘substance’ to concepts of ‘function’ is characteristic of the historical development of science. ‘Thing-concepts’ have gradually and often painfully yielded to ‘relational concepts’. Even Freud, some critics have insisted, is still a ‘substance’ thinker. In this connexion Dr Hayek’s theory appears very modern indeed since not even traces of ‘thing-concepts’ are left in his theory. ‘Mind’ for him has turned into a complex of relations; it is simply ‘a particular order of a set of events taking place in some organism and in some manner related to, but not identical with, the physical order of events in the environment’. In addition, his theory, perhaps more than any other, emphasizes the far-reaching importance of ‘experience’ and ‘learning’. Certain theories have always stressed the factor of ‘experience’ while others have stressed the importance of the conditions, structures, or presuppositions which make experience possible. The relations between these two sets of factors, however, present peculiar difficulties. In elucidating the complexity of these relations, Dr Hayek probably makes his most important and original contributions. It has been said that there are no permanent or fixed ‘objects’, but only ways of knowing ‘objectively’. The implication of the theory presented here is that even the ways of knowing ‘objectively’ are not stable, or only relatively stable, and that the ordering principles themselves are subject to change. Dr Hayek, therefore, does not take a static view of either the ‘elements’ or the ‘relational’ structure involved in the sensory or any other kind of order. Conceptual thinking, as he rightly emphasizes, has long been recognized as a process of continuous reorganization of the (supposedly constant) elements of the phenomenal world. In his opinion, however, there is no justification for the sharp distinction between the more abstract processes of thought and direct sensory perception since the qualitative elements, of which the phenomenal world is built up, and the whole order of the sensory qualities are themselves subject to continuous change. The fact that there can be nothing in our mind which is not the result of ontogenetically or phylogenetically established ‘linkages’ is not meant to exclude processes of reclassification. At the same time it is to be clearly understood that at least a certain part of what we know at any moment about the external world is not learned by sensory experience, but is rather implicit in the means through which we can obtain such experience; that is, it is determined by the order of the previously established apparatus of classification. To express it differently, there is, on every level, a part of our knowledge which, although it is the result of experience, cannot be controlled by experience because it constitutes the ordering principle. In considering the implications of Dr Hayek’s theory, the impression is gained that not only the characteristics and properties of the organism involved in ‘classifying’ activities but also the characteristics of the ‘environment’ appear in a new light. Man occupies only a small corner of the terrestrial biosphere, including the recently developed, chemically highly active, and man-made anthroposphere of A. P. Pavlov. If pre-sensory and sensory ‘linkages’ are formed not only during the life of the individual, but also in the course of phylogenetic development, the characteristics of the environment, in which the building-up of the apparatus of classification or orientation occurs, assume special importance. If the apparatus of classification is shaped by the conditions in the environment in which we live and if it represents a kind of map or reproduction of relations between elements of this environment, the question arises as to the extent to which environmental factors ‘colour’ or ‘condition’ principles of ordering. Perhaps Vernadsky’s bio-geochemistry has, in the light of Dr Hayek’s theory, unexpected psychological implications. In the meantime, the striking results on ‘conditioned sensations’ recently obtained by Ivo Kohler have demonstrated how strongly environmental factors and conditions may influence sensory phenomena during the life of an individual.

It is not possible to comment in detail on the skill and knowledge with which Dr Hayek has utilized psychological, physiological, and other data to support his thesis and to enumerate the many problems and theories upon which his penetrating analysis has significant bearing. His concepts of the ‘map’, the ‘model’, and related concepts appear to be promising tools in analysing brain mechanisms and behaviour. What is perhaps most pertinent is that his theory suggests definite lines of experimentation. For instance, it should be possible not only to change sensory qualities experimentally, but to create altogether new sensory qualities which have never been experienced before. The psychologist is likely to find this theory helpful in devizing new experiments even beyond the scope indicated by the author himself. In considering the consequences and implications of his own theory and in trying to define its content as unambiguously as possible, the author does not hesitate to point out that an experimental confirmation of theories, such as Semon’s ‘engram’ theory or Paul Weiss’s ‘resonance’ theory, would disprove his own theory.

A great historian once expressed the view that ‘no man, and no product of all a man’s labour either, is like a perfectly thought-out book, and merely to point out lacunae in some pages and deficiences in others must seem much more an envious job of rival contemporaries than a historian’s true duty . . . ’ When viewing the complex structure of a psychological theory, envious ‘rival contemporaries’ undoubtedly will always try, no matter how difficult the job may be, to establish that certain petits faits signicatifs or even merely ‘little facts’ have not been built into the edifice. About twenty years ago, Lashley, in commenting on an experimental investigation concerned with analysing the interdependence of relations and relata and establishing forms of invariance in behaviour, spoke of ‘the tracing of relations through the intricate web of dependent processes which is mind‘. Dr Hayek has done more than his share in tracing relations through the intricate web of ‘mind’. His is one of the most interesting and significant books on theoretical psychology that has appeared in this country during the last decades.

CHAPTER I

THE NATURE OF THE PROBLEM

I. WHAT IS MIND?

1.1. The nature of the subject of this study makes its first task the most important and the most difficult: clearly to state the problem to which it will attempt an answer. We shall have moved a considerable distance towards the solution of our problem when we have made its meaning precise and have shown what kind of statement could be regarded as a solution.

1.2. The traditional heading under which our problem has been discussed in the past is that of the ‘relation’ between mind and body, or between mental and physical events. It can also be described by the questions of ‘What is mind?’ or ‘What is the place of mind in the realm of nature?’ But while these expressions indicate a general field of inquiry, they do not really make it clear what it is that we want to know. Before we can successfully ask how two kinds of events are related to each other (or connected with each other), we must have a clear conception of the distinct attributes by which they can be distinguished. The difficulty of any fruitful discussion of the mind-body problem consists largely in deciding what part of our knowledge can properly be described as knowledge of mental events as distinguished from our knowledge of physical events.

1.3. We shall attempt to avoid at first at least some of the difficulties of this general problem by concentrating on a more definite and specific question. We shall inquire how the physiological impulses proceeding in the different parts of the central nervous system can become in such a manner differentiated from each other in their functional significance that their effects will differ from each other in the same way in which we know the effects of the different sensory qualities to differ from each other. We shall have established a ‘correspondence’ between particular physiological events and particular mental events if we succeed in showing that there can exist a system of relations between these physiological events and other physiological events which is identical with the system of relations existing between the corresponding mental events and other mental events.

1.4. We select here for examination the problem of the determination of the order of sensory qualities because it seems to raise in the clearest form the peculiar problem posed by all kinds of mental events. It will be contended that an answer to the question of what determines the order of sensory qualities constitutes an answer to all questions which can be meaningfully asked about the ‘nature’ or ‘origin’ of these qualities; and further, that the same general principle which can be used to account for the differentiation of the different sensory qualities serves also as an explanation of the peculiar attributes of such other mental events as images, emotions, and abstract concepts.

1.5. For the purposes of this discussion we shall employ the term sensory ‘qualities’ to refer to all the different attributes or dimensions with regard to which we differentiate in our responses to different stimuli. We shall thus use this term in a wide sense in which it includes not only quality in the sense in which it is contrasted with intensity, extensity, clearness, etc., but in a sense in which it includes all these other attributes of a sensation.¹ We shall speak of sensory qualities and the sensory order to distinguish these from the affective qualities and the other mental ‘values’ which make up the more comprehensive order of ‘mental qualities’.

2. THE PHENOMENAL WORLD AND THE PHYSICAL WORLD

1.6. A precise statement of the problem raised by the existence of sensory qualities must start from the fact that the progress of the physical sciences has all but eliminated these qualities from our scientific picture of the external world.² In order to be able to give a satisfactory account of the regularities existing in the physical world the physical sciences have been forced to define the objects of which this world exists increasingly in terms of the observed relations between these objects, and at the same time more and more to disregard the way in which these objects appear to us.

1.7. There exist now, in fact, at least two³ different orders in which we arrange or classify the objects of the world around us: one is the order of our sense experiences in which events are classified according to their sensory properties such as colours, sounds, odours, feeling of touch, etc.; the other is an order which includes both these same and other events but which treats them as similar or different according as, in conjunction with other events, they produce similar or different other external events.

1.8. Although the older branches of physics, particularly optics and acoustics, started from the study of sensory qualities, they are now no longer directly concerned with the perceptible properties of the events with which they are dealing. Nothing is more characteristic of this than the fact that we find it now necessary to speak of ‘visible light’ and ‘audible sound’ when we want to refer to the objects of sense perception. To the physicist ‘light’ and ‘sound’ now are defined in terms of wave motions, and in addition to those physical events, which, as is true of certain ranges of ‘light’ and ‘sound’ waves, cause definite sense experiences, he deals with imperceptible events like electricity, magnetism, etc., which do not directly produce specific sensory qualities.⁴

1.9. Between the elements of these two orders there exists no simple one-to-one correspondence in the sense that several objects or events which in the one order belong to the same kind or class will also belong to the same kind or class in the other order. They constitute different orders precisely because events which to our senses may appear to be of the same kind may have to be treated as different in the physical order, while events which physically may be of the same or at least a similar kind may appear as altogether different to our senses.

1.10. These two orders have been variously described by different authors as the subjective, sensory, sensible, perceptual, familiar, behavioural or phenomenal⁵ world on the one hand, and and as the objective, scientific, ‘geographical’, physical, or sometimes ‘constructional’ on the other. In what follows we shall regularly employ the pair of terms ‘phenomenal’ and ‘physical’⁶ to describe the order of events perceived in terms of sensory qualities and the order of events defined exclusively in terms of their relations respectively, although we shall occasionally employ the term ‘sensory’ as equivalent to phenomenal, especially (as in the title of this book) in the phrase ‘sensory order’. We shall later (Chapters V and VIII) also describe these two orders as the ‘macrocosm’ and the ‘microcosm’ respectively. Their relation is the central problem of this book.

1.11. It is important not to identify the distinction between the phenomenal and the physical order with the distinction between either of these and what in ordinary language is described as the ‘real’ world. The contrast with which we are concerned is not between ‘appearance’ and ‘reality’ but between the differences of events in their effects upon each other and the differences in their effects on us. It is indeed doubtful whether on the plane on which we must examine these problems the term ‘real’ still has any clear meaning.⁷ For the purposes of our discussion, at any rate, we shall not be interested in what a thing ‘is’ or ‘really is’ (whatever that may mean), but solely in how a particular object or event differs from other objects or events belonging to the same order or universe of discourse. It seems that a question like ‘what is x?’ has meaning only within a given order, and that within this limit it must always refer to the relation of one particular event to other events belonging to the same order. We shall see that the mental and the physical world are in this sense two different orders in which the same elements can be arranged; though ultimately we shall