A History of Psychology

From Antiquity to Modernity

Thomas Hardy Leahey

• Publisher: Routledge
• Year: 2017
• ISBN:
  9781317228486
• Edition: 8
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

A History of Psychology places social, economic, and political forces of change alongside psychology's internal theoretical and empirical arguments, illuminating how the external world has shaped psychology's development, and, in turn, how the late twentieth century's psychology has shaped society. Featuring extended treatment of important movements such as the Enlightenment and the Scientific Revolution, the textbook approaches the material from an integrative rather than wholly linear perspective. The text carefully examines how issues in psychology reflect and affect concepts that lie outside the field of psychology's technical concerns as a science and profession.

This new edition features expanded attention on psychoanalysis after its founding as well as new developments in cognitive science, artificial intelligence, and behavioral economics. Throughout, the book strengthens its exploration of psychological ideas and the cultures in which they developed and reinforces the connections between psychology, modernism, and postmodernism. The textbook covers scientific, applied, and professional psychology, and is appropriate for higher-level undergraduate and graduate students.

Part I

Situating Psychology

Chapter 1

Introduction

Figure 1.1When Wilhelm Wundt proclaimed the founding of psychological science, he said it was the outcome of an “alliance” between philosophical psychology and the new science of physiology. While this ambition proved premature, it is now coming to fruition in cognitive neuroscience, which uses methods undreamed of by Wundt to connect mind and brain.

Source: Bettmann / Getty Images.

Understanding Science

Plato observed that philosophy begins in wonder. Science also begins in wonder—wonder at the inner workings of nature—and all sciences, including psychology, were originally part of philosophy. Over the centuries, the special sciences gradually became independent of philosophy. Psychology was one of the last of the special sciences to separate from the parent, remaining part of philosophy until the nineteenth century. The founders of psychology were philosophers as well as psychologists, attempting to find scientific answers for many philosophical questions.

Psychology means psyche-logos, literally, the study of the soul, though the term was not coined until the seventeenth century and was not widely used until the nineteenth century. Philosophers and religious teachers around the world have wrestled with the nature of the soul: Does the soul exist? What is its nature? What are its functions? How is it related to the body? While psychologists resist the term soul, preferring the less religiously loaded term mind, they have continued to address these vexing questions. Even psychologists who define psychology not as the study of the mind but as the study of behavior have different answers to these questions.

Since the time of the ancient Greeks, philosophers have inquired into how human beings know the world. This enterprise is called epistemology, from the Greek words episteme (knowledge) and logos (discourse). Asking how human beings know the world involves questions about sensation, perception, memory, and thinking—the whole realm of what psychologists call cognitive psychology.

Ethics is another area shared by philosophers (and religious thinkers) and psychologists. Although ethics is centrally concerned with how people ought to act, practical ethics depends on a conception of human nature. Are people, by nature, good? What motives do people have? Which ones are wholesome and which should be repressed? Are people social by nature? Is there a common good life all humans ought to live? Such questions are profoundly psychological and can be informed by scientific research on human nature. Ethical concerns manifest themselves in many areas of psychology. In scientific psychology, we find them in the studies of motivation and emotion, social behavior, and sexual behavior. Applied psychology, whether in business, industry, government, or in individual clinical and counseling psychology, is deeply involved in human ethics. People come to psychologists wanting to be happier or more productive, seeking the psychologist’s scientifically informed help. The psychologist’s knowledge of motivation, emotion, learning, and memory gives him or her tools to change behavior, but the psychologist must not be merely the client’s servant. A business-consulting psychologist may need to tell a client that he or she is the problem in the company, and no ethical psychologist would teach a con artist how to improve his or her self-presentation skills. Science is traditionally value-neutral in pursuing the secrets of nature, but, as Francis Bacon said, “Knowledge is power,” and the tools of the applied scientist must be rightly used.

Although the conceptual foundations of psychology are to be found in philosophy, the inspiration for the creation of an independent science of psychology came from biology. The idea that the functions philosophers and others ascribed to the mind depended on underlying processes of the brain had been fitfully entertained since the days of the Greeks but had attained the status of a conviction by the mid-nineteenth century. The founders of psychology hoped that, by taking a path to the mind through physiology, what had been speculative philosophy and religion might become naturalistic science. A younger branch of biology—evolution—also shaped the founding of scientific psychology. Especially in Britain and America, philosophers and psychologists began to ask what the mind was good for in the struggle for existence that was evolution by natural selection. Why should we be conscious at all? Were animals conscious? These new questions would disturb, yet animate, psychologists from the beginning. Therefore, we will be concerned not just with the abstract questions of philosophy, but with the growing understanding of the brain and nervous system from the Classical era to the present.

Modes of Scientific Explanation

From the nineteenth century onward there has been general agreement that psychology is, or at least ought to be, a science. The nature of science—what psychology aspires to be—is a good starting point for understanding it. People expect science to explain how and why the world, the mind, and the body work as they do. Philosophy of science tries to understand how science works (Rosenberg, 2005). The modern style of scientific explanation began with Isaac Newton and the Scientific Revolution (see chapter 5).

Box 1.1
Positivism

Positivism was a self-consciously modern movement, and thus part of modernism even before the term came into use. It began with a rather eccentric Frenchman named Auguste Comte (1798–1857) and his positive philosophy. It wasn’t positive in the sense of “positive psychology,” but positive in a philosophical way. His enemy was speculative philosophy that trucked with unseen things like gods and Forms, and he wanted to replace it with a philosophy based on directly observable—positive—facts (if there are such things). He saw human history as passing through three stages, the first two of which were based on speculative philosophy. During the theological stage, people thought that gods caused events and the natural rulers of society were thus priests, who supposedly understood the gods and could entreat or control them to human advantage. The second stage was the metaphysical stage. People (or at least the elite) no longer believed that gods controlled the world, but did believe in unseen essences and forces that did. The natural rulers were thus kings and aristocrats—the elites—who understood these hidden Truths; we’ll meet them as Plato’s Guardians in the next chapter.

The last—modern—stage was the scientific stage. Gods and metaphysics were jettisoned for Newtonian science, which understood the genuine causes of events and which could therefore really deliver the goods for human welfare in a way that priests and aristocrats could only fake—to their own interest, rather than humanity’s. The natural rulers would thus be scientists, specifically the scientists whose expertise was society itself—sociologists. Psychologists would count themselves among the number of the new elite. As founding psychologist James McKeen Cattell wrote, “Scientific men should take the place that is theirs as masters of the modern world” (quoted by Herman, 1996, p. 55).

The Nomological Approach: Explanation by Laws of Nature

Newton defined his scientific enterprise as the search for a small number of mathematical laws from which one could deduce observed regularities in nature. His domain was the physics of motion, which he proposed to explain in terms of three laws of motion and a law of gravity, and he showed how his laws could precisely account for the movement of the bodies in the solar system. As an example of the Newtonian style of explanation (Cohen, 1980), we will take the law of gravity: Between any two bodies there is a mutually attracting force whose strength is inversely proportional to the square of the distance between them. Newton was criticized by his contemporaries for failing to provide any mechanism to explain how gravity worked; to them, action at a distance between two objects smacked of magic. Newton, however, replied, “Hypotheses non fingo,” “I do not feign [propose] hypotheses.” Newton refused, in other words, to explain his principle of gravity; for him, it was sufficient to postulate a force from which one could predict the motions of the heavenly bodies.

With Newton began a new philosophy for understanding nature that was later codified in an extreme form by Auguste Comte (1798–1857) and his followers, the positivists (see chapter 7), who said science worked because of the Newtonian style of remaining as close as possible to the observable facts and as far as possible from hypothetical explanations. Thus the basic job of science is description rather than explanation. Scientists are supposed to closely observe nature, looking for regular occurrences and reliable correlations. On the basis of their observations, scientists would propose scientific laws, such as Newton’s law of gravity. Extending Newton’s reluctance to frame hypotheses, positivists understood scientific laws to be mathematical summaries of past observations rather than truths of nature.

From the first function of science, description, ideally summarized as laws, arises the second function, prediction. Using Newton’s law of gravity and his three laws of motion, scientists could predict future events, such as eclipses and the return of comets. Finally, prediction from laws made control of nature possible. Using Newton’s laws, engineers could calculate the thrust required to throw satellites into precise orbits around the earth and send probes to the distant planets. Knowledge, as Francis Bacon said, is power, and control was the ultimate rationale for science in the positivist’s philosophy. Comte looked forward to the scientific rule of society, and the desire to apply scientific psychological expertise to Comte’s project played an important role in shaping twentieth-century psychology.

Description, prediction, and control were the only three functions assigned to science by the first positivists. They regarded the human desire for explanations—answers to why questions—as a dangerous temptation to indulge in metaphysical and theological speculation. However, in 1948, the contemporary era of philosophical understanding of explanation began with the publication of “Studies in the Logic of Explanation” by two logical positivists, Carl Hempel and Paul Oppenheim. Their “epoch-making” (Salmon, 1989) paper showed a way of incorporating an explanatory function for science within the positivist framework, and, despite its age and defects, the Hempel–Oppenheim model of explanation remains the starting point for all subsequent studies of explanation in science.

Hempel and Oppenheim proposed that scientific explanations could be regarded as logical arguments in which the event to be explained, the explanandum, could be deduced from the explanans—relevant scientific laws and the observed initial conditions. So a physicist would explain a solar eclipse by showing that, given the relative position of sun, moon, and earth sometime before the eclipse, one could use Newton’s laws of motion and gravity to deductively predict their arrival into an eclipse-producing alignment. Since Hempel and Oppenheim said that explanations are deductions from scientific laws, their scheme is called the deductive-nomological (from the Greek nomos, “law”) model of explanation. It is also called the covering-law model of explanation, since an explanation shows how an event is subsumed, or covered, under some set of scientific laws.

Certain features of the Hempel–Oppenheim model are important. First, it makes explicit a central and crucial feature of explanation that I will call the Iron Law of Explanation: The explanandum may not be contained explicitly or implicitly in the explanans. Violation of this rule renders an explanation null and void on grounds of circularity. An example borrowed from the French playwright Molière illustrates a circular explanation. Imagine asking “Why does Somitol make me sleepy?” and receiving the reply “Because it possesses the soporific power!” At first glance, this appears to be an explanation of one thing (sleepiness) in terms of another (soporific power), and indeed, stated forcefully in an advertisement, it might be able to pass itself off as one. However, when we learn that “soporific” means “sleep-inducing,” we see that the proffered explanation is empty because it says, in effect, Somitol makes you sleepy because it makes you sleepy. The explanandum, causing sleep, was implicitly contained in the explanans, so the explanation was circular. The Iron Law is easy to violate because we often think when we have named something—the soporific power—that we have explained it. Because much of the mind cannot be observed, violating the Iron Law is especially easy in psychology. We may think we have explained why someone is shy and has few friends by calling him or her an “introvert,” but all we have done is given a shorthand label to a person who is shy and has few friends. If introversion is to be a real explanation of being shy, it must be linked to something other than shy behavior, perhaps to a genetic predisposition.

A more controversial feature of the deductive-nomological model is that it sees prediction and explanation as the same thing. In the Hempel–Oppenheim model, the explanation of an event consists of showing that it could have been predicted. Thus, an astronomer predicts an eclipse in the year 2010 but explains one in 1010. In each case, the procedure is the same—applying the laws of motion to the state of the sun, moon, and earth, and demonstrating the inevitability of the eclipse. However, the thesis that explanation and prediction are symmetrical runs into important problems. Consider a flagpole and its shadow (Rosenberg, 2005). If one knows the height of a flagpole and the position of the sun, one can deduce and so predict the length of the shadow from the laws governing light and the rules of geometry, and it seems reasonable to say that we have thereby explained the length of the shadow. By the same token, however, if we know the length of the shadow, we can deduce and so “predict” the height of the flagpole, but surely the length of the shadow does not explain the height of the flagpole.

The Causal Approach: Laws Are Not Enough

The covering-law model for scientific explanation deliberately avoids questions about the real causal structure of nature, preferring to focus instead on how we can predict and control nature. Usable knowledge need not pretend to be profound or true. Although how aspirin works is only now being understood, physicians have long prescribed it to relieve pain, inflammation, and fever. Following Newton, who refused to worry about why his laws of motion were true, positivists demand of scientific explanations only that they make successful predictions, not that they reveal why they do so. Discomfited by the shortcomings of the positivist approach, some philosophers want science to probe deeper, telling us not merely how nature works as it does, but why it works as it does.

The main rival to the positivist approach to explanation is the causal approach (e.g., Salmon, 1984). Its starting point is the difficulty of identifying explanation with prediction. Although we can deduce the height of a flagpole from the length of its shadow, shadows cannot cause anything, and so they should not be cited in explanations; in contrast, objects blocking rays from the sun causally cast shadows. The mere existence of a predictive regularity is not the same as a law of nature, no matter how reliable and useful the regularity may be. The generalization “When the reading on a barometer drops, a storm will occur” states a useful correlation, not a causal law of nature.

More importantly for the explanation of human behavior, we intuitively accept explanations that cite no laws at all. When in the last chapter of a murder mystery the detective unravels the crime, explaining who did it, how, and why, he or she will not invoke laws of nature. Instead, he or she will show how a series of particular, unique events led, one after the other, to the commission of murder. We feel satisfied to learn that Lord X was murdered by his son to pay his gambling debts, but there is no law of nature saying “All (or even most) sons with gambling debts will kill their fathers.” Much explanation in everyday life and history is of this type, connecting events in a causal sequence without the mention of laws. No...