Central Controversies

The new field of psychology was shaped by disputes over its definition and scientific nature.

Subject Matter

What does psychology study? The Cartesian paradigm gave one answer: Psychology is the study of consciousness, and the first psychologists defined psychology as the science of consciousness. They claimed a fixed subject matter, consciousness, and a unique method, introspection, for examining it. However, no science of human nature could completely avoid studying what people do. In Germany, Immanuel Kant proposed a science of behavior called anthropology, and in Britain, John Stuart Mill proposed a similar science called ethology. As the human sciences sorted themselves out in the nineteenth and twentieth centuries, psychology gradually extended its scope to include everything about human beings as individuals, adding the studies of individual behavior and individual differences to the study of consciousness. The other human sciences came to focus on human society (sociology), culture (anthropology), and history.

A Science and Its Methods

Interacting with considerations concerning psychology’s subject matter was psychology’s status as a science. Could psychology, especially defined as the study of consciousness, be a science at all? If so, what sort of science should it be and what methods should it use? These questions were debated throughout the nineteenth century Some thinkers, especially the post-Kantian German idealists and the founder of positivism, Auguste Comte (1798-1857), expressed serious reservations about whether there could be a science of mind and consciousness at all.

Idealists doubted that conscious experience, the empirical ego, could be quantitatively measured. Experience might be qualitatively described, but without numerical measurement in more than one dimension, there could be no mental equivalent of Newton’s mathematical laws, and thus no science of the mind. More important was the impossibility of studying the self, the transcendental ego. Because the self had experiences, the idealists held, it could not become an object of experience. Thus, the higher mental processes could not be observed. A psychology from which the study of thought, human’s greatest possession, was excluded, would not deserve the name of science.

Comte proposed a hierarchy of sciences from which psychology was pointedly excluded. The most basic science was physics, upon which was founded chemistry, upon which was founded biology, upon which was founded the most recent and ultimate science, sociology, The soul (psuche) did not exist, Comte held, so there could be no science (logos) of it. He hoped that phrenology, a biological science of the brain, would provide the knowledge of human nature needed by sociologists. Comte’s ideas were later refined by the logical positivists, whose philosophy of science provided arguments for redefining psychology as the science of publicly observable behavior.

In Great Britain, empiricist philosophers developed an alternative conception of the mind friendlier to its scientific treatment. Most significant for psychology was Mill (1806-1873), who answered Kant and Comte directly. Surely, he argued, we can observe consciousness, behavior, and some aspects of thought with varying degrees of rigor, and build up a discipline of the mind. Like meteorology, such a discipline might never achieve the precision of physics, but it would be worthy of the name of science and be practically useful. Mill’s pragmatic approach to defining science and psychology continued in his friend and successor Alexander Bain (1818-1903), and through him, in early American psychology. Prior to the Civil War, however, American psychology was virtually synonymous with the morally oriented psychology of the eighteenth-century Scots.

A third, often vocally dissident, tradition arose in Germany, drawing inspiration from Giambattista Vico and Johann Herder. Idealists and empiricists differed over to what degree psychology could be a science, but they agreed that if psychology was going to be a science. it should aspire to discover the laws governing mind and behavior. The model for psychology (and the other human sciences) was physics. As Mill put it, “The backward state of the moral sciences can only be remedied by applying to them the methods of physical science, duly extended and generalized.” Mill’s scheme was put into action by the first psychology laboratories. Against Mill’s idea (shared by the positivists) that all sciences should be modeled on physics, the historian Wilhelm Dilthey (1833-1911) said that there was not one kind of science, but two: Naturwissenschft (“natural science”) for whom the model was physics, aiming at laws, prediction, and control; and Geisteswissenschaft (literally, “spiritual science,” usually translated as “human science.” a term used here to include all sciences that study human beings by whatever method) was modeled after history. Historians typically seek no universal laws, but attempt to explain particular chains of unique events by trying empathetically and sympathetically to enter into a past culture and its people, aiming not at prediction and control, but at what Dil­they called Verstehen (“understanding”).

The concerns of Vico, Herder, and Dilthey are connected with one the most profound and difficult issues facing the scientific explanation of human mind and behavior. Philosopher Georg Friedrich Wilhelm Hegel (1770-1831) first stated the issue in its modern form: Natural science deals with the causes of events, but human action involves reasons and motives that are not physical causes. Suppose a woman shoots her husband one night. The killing is murder if she intended to kill him for an inheritance. However, it may have been a horrible accident: she may have thought that she was shooting an intruder. From the standpoint of natural science, the cause of the event is the same, a bullet entering a brain, but to understand what happened in human terms—and thus to decide between murder and accident—we must look into the wife’s mind as she pulled the trigger. Motives and reasons are related to human moral (social) life, not to our physical lives, and therefore it was (and is) unclear how they should be treated by natural science.

Only in Germany were challenges to psychology as a natural science proposed, and psychologists ultimately rejected them. Elsewhere, psychologists followed the Newtonian path with little debate. Nevertheless, although Dilthey’s has been a minority perspective, it has offered important critiques of mainstream natural science psychology. In the twentieth century, the herme­neutic movement has viewed psychology more like literary criticism than science, and the followers of Ludwig Wittgenstein (1889-1951) have wrestled with the place of reasons, motives, and social contexts in human behavior.

Empiricism and Idealism

In addition to quarreling over psychology’s methods and aspirations, idealists and empiricists waged a battle over the nature of mind and reality. Empiricists subordinated the subjective to the objective, and idealists subordinated the objective to the subjective. Although this battle was over metaphysics, it nevertheless shaped the early definition and development of psychology. (This statement is a serious but unavoidable overgeneralization for a short article. There were empiricists, such as William James in his radical empiricism and some later positivists, who agreed with the idealists that the only knowable reality was the world of ideas. The key distinction here is the split between empiricists who viewed the mind as relatively passive and idealists who saw it as active.) Both groups accepted the general picture of the Cartesian theater, agreeing that consciousness is a screen of ideas, but disagreed about what lay beyond and underneath consciousness.

Empiricists identified mind with consciousness and depicted consciousness as a surface onto which ideas were directly projected by sensory processes in the brain. In this view, consciousness was a mirror of nature, the image on the mind’s view screen directly reflecting the reality outside the person. Ideas containing more than one distinct sensation were thought of as compounds made up of many atomic sensory units bound together on the screen of consciousness by association, just as distinct objects in space are bound together by gravity. This picture of the mind was developed most fully by British philosophers from Locke to Mill, but also influenced French and German psychology, especially after the rise of positivism.

In empiricists’ hands, psychology, defined as the science of consciousness, became a kind of mental chemistry. Its job was to identify the basic elements of conscious experience (as the periodic table lists the basic physical elements) and to describe the laws that regulate their combination (as chemistry describes the laws regulating how atoms combine to form molecules). To this introspective task was added the goal of linking sensory experience and association formation to underlying physiological processes. This kind of psychology was a tendency in all early psychology laboratories, but was most pronounced in English and American ones. Its purest expression was in Edward Bradford Titchener’s (1867-1927) structural psychology.

Idealists followed Kant in refusing to identify mind with consciousness. Consciousness (the relatively trivial empirical ego) was a surface, but under this surface was the transcendental ego, the self. Moreover, consciousness was not a mirror of the world outside. The transcendental ego imposed necessary and universal categories of understanding on perceptions, constructing reality as we know it. Some idealists went further, saying the self posited the outside world into existence. Empiricists subordinated the subjective world of consciousness to the objective world it reflected, and the self disappeared. Idealists subordinated the objective world to the self, and physical reality disappeared. Unsurprisingly, idealism linked up with Romanticism. Romantic emphasis on feeling and creativity sat ill with empiricism’s passive, mirror mind, but fit well with idealism’s profound and powerful self that posited the world by its own will.

The philosophy of idealism had important implications for psychology as the study of consciousness. The most important concerned the scope of scientific psychology and the existence and nature of will. By setting the transcendental ego outside the possibility of experience, it implied that thought and other higher mental processes perforce eluded scientific study. The German founder of psychology, Wilhelm Wundt (1832-1920), originally held that introspection and physiology could study and explain thought as well as consciousness, giving his early writings more resonance with empiricism than his later ones, in which he accepted idealist strictures on the experimental study of thought. In these, Wundt made common cause with the Vico-Herder-Dilthey thesis in order to create a complete science of mind. He divided psychology into two parts. One, physiological psychology, was the experimental study of consciousness, linked increasingly weakly to the study of the nervous system. The other, Volkerpsychologie (literally, “folk psychology”; however, this and all other translations are misleading), was the nonexperimental study of thought and most other higher mental processes through their expression in language, myth, and culture.

Idealists and Romantics exalted the human will. Wundt reflected the idealist spirit, calling his psychology “voluntaristic.” James so believed in will that he left psychology to develop his own form of idealism and his vision of a morally strenuous life. Nevertheless, idealism soon vanished from psychology. Outside Germany, empiricism, positivism, and materialism sharply limited its influence, and psychology proceeded as a comprehensive science on the model of physics. In Germany, similar ideas triumphed among Wundt’s rivals, who emphasized experimentation and a thoroughgoing naturalism. His Volkerpsychologie went largely unread, and he was not invited to the first meeting of the German Society for Experimental Psychology in 1904. Still, idealist influences persist, for example, mildly in the cognitive psychology of perception and memory, and radically in the movements of contextualism and constructivism. Cognitive psychologists do not assert that the mind posits the world, but do say that the world as we experience and remember it is shaped by an active mind. Contextualists and constructivists deride the idea of objective truth (that mind can mirror nature), and insist that all knowledge is socially constructed.