Principles of Physiological Psychology by Wilhelm Wundt
THE title of the present work is in itself a sufficiently clear indication of the contents. In it. the attempt is made to show the connexion between two sciences whose subject-matters are closely interrelated, but which have, for the most part, followed wholly divergent paths. Physiology and psychology cover, between them, the field of vital phenomena: they deal with the facts of life at large, and in particular with the facts of human life.
Physiology is concerned with all those phenomena of life that present them selves to us in sense perception as bodily processes, and accordingly form part of that total environment which we name the external world. Psychology, on the other hand, seeks to give account of the interconnexion of processes which are evinced by our own consciousness, or which we infer from such manifestations of the bodily life in other creatures as indicate the presence of a consciousness similar to our own.
This division of vital processes into physical and psychical is useful and even necessary for the solution of scientific problems. We must, however, remember that the life of an organism is really one: complex, it is true, but still unitary. We can. therefore, no more separate the processes of bodily life from conscious processes than we can mark off an outer experience, mediated by sense perceptions, and oppose it, as something wholly separate and apart, to what we call ‘inner’ experience, the events or our own consciousness.
On the contrary: just as one and the same tiling, e.g., a tree that I perceive before me, falls as external object within the scope of natural science, and as conscious contents within that of psychology, so there are many phenomena of the physical life that are uniformly connected with conscious processes, while these in turn are always bound up with processes in the living body. It is a matter of every-day experience that we refer certain bodily movements directly to volitions, which we can observe as such only in our consciousness.
Conversely, we refer the ideas of external objects that arise in consciousness either to direct affection of the organs of sense, or, in the case of memory images, to physiological excitations within the sensory centres, which we interpret as after-effects of foregone sense impressions.
It follows, then, that physiology and psychology have many points of contact. In general there can of course be no doubt that their problems are distinct. But psychology is called upon to trace out the relations that obtain between conscious processes and certain phenomena of the physical life: and physiology, on its side, cannot afford to neglect the conscious contents in which certain phenomena of this bodily life manifest them selves to us. Indeed, as regards physiology, the interdependence of the two sciences is plainly in evidence.
Practically everything that the physiologists tell us, by way of fact or of hypothesis, concerning the processes in the organs of sense and in the brain, is based upon determinate mental symptoms: so that psychology has long been recognised, explicitly or implicitly, as an indispensable auxiliary of physiological investigation. Psychologists, it is true, have been apt to take a different attitude towards physiology.
They have tended to regard as superfluous any reference to the physical organism: they have supposed that nothing more is required for a science of mind than the direct apprehension of conscious processes themselves. It is in token of dissent from any such standpoint that the present work is entitled a “physiological psychology.” We take issue, upon this matter, with every treatment of psychology that is based on simple self-observation or on philosophical presuppositions.
We shall, wherever the occasion seems to demand, employ physiology in the service of psychology. We are thus, as was indicated above, following the example of physiology itself, which has never been in a position to disregard facts that properly belong to psychology. – although it has often been hampered in its use of them by the defects of the empirical or metaphysical psychology which it has found current.
Physiological psychology is. therefore, first of all psychology . It has in view the same principal object upon which all other forms of psychological exposition are directed: the investigation of conscious processes in the modes of connexion peculiar to them. It is not a province of physiology: nor does it attempt, as has been mistakenly asserted, to derive or explain the phenomena of the psychical from those of the physical life.
We may read this meaning into the phrase ‘physiological psychology.’just as we might interpret the title ‘microscopical anatomy’ to mean a discussion, with illustrations from anatomy, of what has been accomplished by the microscope: but the words should be no more misleading in the one case than they are in the other.
As employed in the present work, the adjective ‘physiological’ implies simply that our psychology will avail itself to the full of the means that modem physiology puts at its disposal for the analysis of conscious processes. It will do this in two ways.
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