Wundt-Principles-of-Physiological-Psychology

PrinciplesofPhysiologicalPsychology s s s




by Wilhelm Wundt (1902)
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Translated by Edward Bradford Titchener (1904)
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Introduction

Part I. The Bodily Substrate of the Mental Life Chapter
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s 1. The Organic Evolution of Mental Function Chapter 2.
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s Structural Elements of the Nervous System Chapter 3.
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Physiological Mechanics of Nerve Substance
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Chapter 4. Morphological Development of the Central Organs
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s Chapter 5. Course of the Paths of Nervous Conduction Chapter
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s 6. Physiological Function of the Central Parts
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1

, PrinciplesofPhysiologicalPsychology s s s




by Wilhelm Wundt (1902) s s s




Translated by Edward Bradford Titchener (1904) s s s s s




INTRODUCTION

§1. The Problem of Physiological Psychology
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THE title of the present work is in itself a sufficiently clear indication of the contents. In it, the attempt is
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made to show the connexion between two sciences whose subject-matters are closely interrelated,
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but which have, for the most part, followed wholly divergent paths. Physiology and psychology cover,
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between them, the field of vital phenomena; they deal with the facts of life at large, and in particular
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with the facts of human life. Physiology is concerned with all those phenomena of life that present
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them selves to us in sense perception as bodily processes, and accordingly form part of that total
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environment which we name the external world. Psychology, on the other hand, seeks to give
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account of the interconnexion of processes which are evinced by our own consciousness, or which
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we infer from such manifestations of the bodily life in other creatures as indicate the presence of a
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consciousness similar to our own.
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This division of vital processes into physical and psychical is useful and even necessary for the
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solution of scientific problems. We must, however, remember that the life of an organism is really one;
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complex, it is true, but still unitary. We can, therefore, no more separate the processes of bodily life
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from conscious processes than we can mark off an outer experience, mediated by sense
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perceptions, and oppose it, as something wholly separate and apart, to what we call 'inner'
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experience, the events or our own consciousness. On the contrary: just as one and the same thing,
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e.g., a tree that I perceive before me, falls as external object within the scope of natural science, and
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as conscious contents within that of psychology, so there are many phenomena of the physical life
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that are uniformly connected with conscious processes, while these in turn are always bound up with
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processes in the living body. It is a matter of every-day experience that we refer certain bodily
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movements directly to volitions, which we can observe as such only in our consciousness.
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Conversely, we refer the ideas of external objects that arise in consciousness either to direct
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affection of the organs of sense, or, in the case of memory images, to physiological excitations within
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the sensory centres, which we interpret as after- effects of foregone sense impressions.
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[p. 2] It follows, then, that physiology and psychology have many points of contact. In general there
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can of course be no doubt that their problems are distinct. But psychology is called upon to trace out
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the relations that obtain between conscious processes and certain phenomena of the physical life;
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and physiology, on its side, cannot afford to neglect the conscious contents in which certain
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phenomena of this bodily life manifest them selves to us. Indeed, as regards physiology, the
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interdependence of the two sciences is plainly in evidence. Practically everything that the
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physiologists tell us, by way of fact or of hypothesis, concerning the processes in the organs of sense
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and in the brain, is based upon determinate mental symptoms: so that
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,psychology has long been recognised, explicitly or implicitly, as an indispensable auxiliary of
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physiological investigation. Psychologists, it is true, have been apt to take a different attitude towards
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physiology. They have tended to regard as superfluous any reference to the physical organism; they
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have supposed that nothing more is required for a science of mind than the direct apprehension of
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conscious processes themselves. It is in token of dissent from any such standpoint that the present
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work is entitled a "physiological psychology." We take issue, upon this matter, with every treatment of
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psychology that is based on simple self-observation or on philosophical presuppositions. We shall,
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wherever the occasion seems to demand, employ physiology in the service of psychology. We are
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thus, as was indicated above, following the example of physiology itself, which has never been in a
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position to disregard facts that properly belong to psychology, - although it has often been hampered
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in its use of them by the defects of the empirical or metaphysical psychology which it has found
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current.
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Physiological psychology is, therefore, first of all psychology. It has in view the same principal object s s s s s s s s s s s s s s s




upon which all other forms of psychological exposition are directed: the investigation of conscious
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processes in the modes of connexion peculiar to them. It is not a province of physiology; nor does it
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attempt, as has been mistakenly asserted, to derive or explain the phenomena of the psychical from
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those of the physical life. We may read this meaning into the phrase 'physiological psychology,' just
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as we might interpret the title 'microscopical anatomy' to mean a discussion, with illustrations from
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anatomy, of what has been accomplished by the microscope; but the words should be no more
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misleading in the one case than they are in the other. As employed in the present work, the adjective
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'physiological' implies simply that our psychology will avail itself to the full of the means that modern
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physiology puts at its disposal for the analysis of conscious processes. It will do this in two ways.
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(I) Psychological inquiries have, up to the most recent times, been undertaken solely in the interest of
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philosophy ; physiology was enabled, by [p. 3] the character of its problems, to advance more quickly
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towards the application of exact experimental methods. Since, however, the experimental
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modification of the processes of life, as practised by physiology, oftentimes effects a concomitant
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change, direct or indirect, in the processes of consciousness,--which, as we have seen, form part of
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vital processes at large,--it is clear that physiology is, in the very nature of the case, qualified to assist
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psychology on the side of method; thus rendering the same help to psychology that it, itself received
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from physics. In so far as physiological psychology receives assistance from physiology in the
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elaboration of experimental methods, it may be termed experimental psychology. This name
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suggests, what should not be forgotten, that psychology, in adopting the experimental methods of
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physiology, does not by any means take them over as they are, and apply them without change to a
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new material. The methods of experimental psychology have been transformed--in some instances,
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actually remodelled--by psychology itself, to meet the specific requirements of psychological
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investigation. Psychology has adapted physiological as physiology adapted physical methods, to its
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own ends.
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(2) An adequate definition of life, taken in the wider sense, must (as we said just now) cover both the
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vital processes of the physical organism and the processes of consciousness. Hence, wherever we
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meet with vital phenomena that present the two aspects, physical and psychical there naturally
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arises a question as to the relations in which these aspects stand to each other. So we come face to
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face with a whole series of special problems, which may be occasionally
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, touched upon by physiology or psychology, but which cannot receive their final solution at the hands
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of either, just by reason of that division of labour to which both sciences alike stand committed.
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Experimental psychology is no better able to cope with them than is any other form of psychology,
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seeing that it differs from its rivals dilly in method, and not in aim or purpose.
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Physiological psychology, on the other hand, is competent to investigate the relations that hold s s s s s s s s s s s s s




between the processes of the physical and those of the mental life. And in so far as it accepts this
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second problem, we may name it a psychophysics.[1] If we free this term from any sort of
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metaphysical implication [p. 4] as to the relation of mind and body, and understand by it nothing more
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than an investigation of the relations that may be shown empirically to obtain between the psychical
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and the physical aspects of vital processes, it is clear at once that psychophysics becomes for us not,
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what it is some times taken to be, a science intermediate between physiology and psychology, but
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rather a science that is auxiliary to both. It must, however, render service more especially to
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psychology, since the relations existing between determinate conditions of the physical
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organization, on the one hand, and the processes of consciousness, on the other, are primarily of
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interest to the psychologist. In its final purpose, therefore, this psychophysical problem that we have
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assigned to physiological psychology proves to be itself psychological. In execution, it will he
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predominantly physiological since psychophysics is concerned to follow up the anatomical and
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physiological investigation of the bodily substrates of conscious processes, and to subject its results
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to critical examination with a view to their bearing upon our psychical life.
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There are thus two problems which are suggested by the title "physiological psychology": the
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problem of method, which involves the application of experiment, and the problem of a
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psychophysical supplement, which involves a knowledge of the bodily substrates of the mental life.
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For psychology itself, the former is the more essential; the second is of importance mainly for the
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philosophical question of the unitariness of vital processes at large. As an experimental science,
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physiological psychology seeks to accomplish a reform in psychological investigation comparable
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with the revolution brought about in the natural sciences by the introduction of the experimental
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method. From one point of view, indeed, the change wrought is still more radical: for while in natural
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science it is possible under favourable conditions, to male an accurate observation without recourse
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to experiment, there is no such possibility in psychology. It is only with grave reservations that what is
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called 'pure self-observation' can properly be termed observation at all and under no circumstances
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can it lay claim to accuracy. On the other hand, it is of the essence of experiment that we can vary the
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conditions of an occurrence at will and, if we are aiming at exact results; in a quantitatively
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determinable way Hence, even in the domain of natural science the aid of the experimental method
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becomes indispensable whenever the problem set is the analysis of transient and impermanent
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phenomena, and not merely the observation of persistent and relatively constant objects. But
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conscious contents are at the opposite pole from permanent objects; they are processes, fleeting
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occurrences, in continual flux and change. In their case, therefore, the experimental method is of
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cardinal importance; it and it alone males a scientific introspection possible. For all accurate
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observational implies that the object [p. 5] of observation (in this case the psychical process) can be
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held fast by the attention, and any changes that it undergoes attentively followed. And this fixation by
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the attention implies, in its turn, that the observed object is independent of the observer. Now it is
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obvious that the required independence does not obtain in any attempt at a direct self-observation,
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undertaken without the help of experiment. The endeavour to observe oneself must inevitably
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introduce
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