An Introduction to the History of Science

by Walter Libby

THE SCIENTIFIC IMAGINATION

Psychology, or the science of mental life as revealed in behavior, has been greatly indebted to physiologists and to students of medicine in general. Any attempt to catalogue the names of those who have approached the study of the mind from the direction of the natural sciences is liable to prove unsatisfactory, and a brief list is sure to entail many important omissions. The mention of Locke, Cheselden, Hartley, Cabanis, Young, Weber, Gall, Müller, Du Bois-Reymond, Bell, Magendie, Helmholtz, Darwin, Lotze, Ferrier, Goltz, Munk, Mosso, Maudsley, Carpenter, Galton, Hering, Clouston, James, Janet, Kraepelin, Flechsig, and Wundt will, however, serve to remind us of the richness of the contribution of the natural sciences to the so-called mental science. Indeed, physiology would be incomplete unless it took account of the functions of the sense organs, of the sensory and motor nerves, of the brain with its association areas, as well as the expression of the emotions, and the changes of function accompanying the development of the nervous system, from the formation of the embryo till physical dissolution, and from species of the simplest to those of the most complex organization.

At the beginning of the nineteenth century the French physician Cabanis was disposed to identify human personality with mere nervous organization reacting to physical impressions, and to look upon the brain as the organ for the production of mind. He soon, however, withdrew from this extreme position and expressed his conviction of the existence of an immortal spirit apart from the body. One might say that the brain is the instrument through which the mind manifests itself rather than the organ by which mind is excreted. Even so, it must be agreed that the relation between the psychic agent and the physical instrument is so close that physiology must take heed of mental phenomena and that psychology must not ignore the physical concomitants of mental processes. Hence arises a new branch of natural science, physiological psychology, or, as Fechner (1860), the disciple of Weber, called it, psycho-physics.

Through this alliance between the study of the mind and the study of bodily functions the intelligence of the lower animals and its survival value, the mental growth of the child, mental deterioration in age and disease, and the psychological endowments of special classes or of individuals, became subjects for investigation. Now human psychology is recognized as contributing to various branches of anthropology, or the general study of man.

Wilhelm Wundt, who, as already implied, had approached the study of the mind from the side of the natural sciences, established in 1875 at the University of Leipzig the first psycho-physical institute for the experimental study of mental phenomena. His express purpose was to analyze the content of consciousness into its elements, to examine these elements in their qualitative and quantitative differences, and to determine with precision the conditions of their existence and succession. Thus science after contemplating a wide range of outer phenomena—plants, animals, earth's crust, heavenly bodies, molecules and atoms—turns its attention with keen scrutiny inward on the thinking mind, the subjective process by which man becomes cognizant of all objective things.

The need of expert study of the human mind as the instrument of scientific discovery might have been inferred from the fact that the physicist Tyndall read before the British Association in 1870 a paper on the Scientific Use of the Imagination, in which he spoke of the imagination as the architect of physical theory, cited Newton, Dalton, Davy, and Faraday as affording examples of the just use of this creative power of the mind, and quoted a distinguished chemist as identifying the mental process of scientific discovery with that of artistic production. Tyndall even chased the psychologists in their own field and stated that it was only by the exercise of the imagination that we could ascribe the possession of mental powers to our fellow creatures. "You believe that in society you are surrounded by reasonable beings like yourself.... What is your warrant for this conviction? Simply and solely this: your fellow-creatures behave as if they were reasonable."

On the traces of this brilliant incursion of the natural philosopher into the realm of mental science, later psychologists must follow but haltingly. Just as in the history of physics a long series of studies intervened between Bacon's hypothesis that heat is a kind of motion (1620) and Tyndall's own work, Heat as a Mode of Motion (1863), so must many psychological investigations be made before an adequate psychology of scientific discovery can be formulated. It may ultimately prove that the passages in which Tyndall and other scientists speak of scientific imagination would read as well if for this term, intuition, inspiration, unconscious cerebration, or even reason were substituted.

At first glance it would seem that the study of the sensory elements of consciousness, motor, tactile, visual, auditory, olfactory, gustatory, thermal, internal, pursued for the last half century by the experimental method, would furnish a clue to the nature of the imagination. A visual image, or mental picture, is popularly taken as characteristic of the imaginative process. In fact, the distinguished psychologist William James devotes the whole of his interesting chapter on the imagination to the discussion of different types of imagery. The sensory elements of consciousness are involved, however, in perception, memory, volition, reason, and sentiment, as they are in imagination. They have been recognized as fundamental from antiquity. Nothing is in the intellect which was not previously in the senses. To be out of one's senses is to lack the purposive guidance of the intelligence.

The psychology of individuals and groups shows startling differences in the kind and vividness of imagery. Many cases are on record where the mental life is almost exclusively in visual, in auditory, or in motor terms. One student learns a foreign language by writing out every word and sentence; another is wholly dependent on hearing them spoken; a third can recall the printed page with an almost photographic vividness. The history of literature and art furnishes us with illustrations of remarkable powers of visualization. Blake and Fromentin were able to reproduce in pictures scenes long retained in memory. The latter recognized that his painting was not an exact reproduction of what he had seen, but that it was none the less artistic because of the selective influence that his mind had exerted on the memory image. Wordsworth at times postponed the description of a scene that appealed to his poetic fancy with the express purpose of blurring the outlines, but enhancing the personal factor. Goethe had the power to call up at will the form of a flower, to make it change from one color to another and to unfold before his mind's eye. Professor Dilthey has collected many other records of the hallucinatory clearness of the visual imagery of literary artists.

On the other hand, Galton, after his classical study of mental imagery (1883), stated that scientific men, as a class, have feeble powers of visual representation. He had appealed for evidence of visual recall to distinguished scientists because he thought them more capable than others of accurately stating the results of their introspection. He had recourse not only to English but to foreign scientists, including members of the French Institute. "To my astonishment," he writes, "I found that the great majority of men of science to whom I first applied protested that mental imagery was unknown to them, and they looked on me as fanciful and fantastic in supposing that the words 'mental imagery' really expressed what I believed everybody supposed them to mean. They had no more notion of its true nature than a color-blind man, who has not discerned his defect, has of the nature of color." One scientist confessed that it was only by a figure of speech that he could describe his recollection of a scene as a mental image to be perceived with the mind's eye.