Stanovich Chapter 1 and 2
Divisions of the American Psychological Association
1. General Psychology 30. Psychological Hypnosis 2. Teaching of Psychology 31. State Psychological Association Affairs 3. Experimental Psychology 32. Humanistic Psychology 5. Evaluation, Measurement, and Statistics 33. Intellectual and Developmental Disabilities 6. Behavioral Neuroscience and Comparative Psychology 34. Population and Environmental Psychology 7. Developmental Psychology 35. Psychology of Women 8. Personality and Social Psychology 36. Psychology of Religion 9. Psychological Study of Social Issues 37. Child and Family Policy and Practice 10. Psychology of Aesthetics, Creativity, and the Arts 38. Health Psychology 12. Clinical Psychology 39. Psychoanalysis 13. Consulting Psychology 40. Clinical Neuropsychology 14. Industrial and Organizational Psychology 41. Psychology and Law 15. Educational Psychology 42. Psychologists in Independent Practice 16. School Psychology 43. Family Psychology 17. Counseling Psychology 44. Psychological Study of Lesbian, Gay, and Bisexual Issues 18. Psychologists in Public Service 45. Psychological Study of Ethnic Minority Issues 19. Military Psychology 46. Media Psychology 20. Adult Development and Aging 47. Exercise and Sport Psychology 21. Applied Experimental and Engineering Psychology 48. Peace Psychology 22. Rehabilitation Psychology 49. Group Psychology and Group Psychotherapy 23. Consumer Psychology 50. Addictions 24. Theoretical and Philosophical Psychology 51. Psychological Study of Men and Masculinity 25. Behavior Analysis 52. International Psychology 26. History of Psychology 53. Clinical Child and Adolescent Psychology 27. Community Psychology 54. Pediatric Psychology 28. Psychopharmacology and Substance Abuse 55. Pharmacotherapy 29. Psychotherapy 56. Trauma Psychology
Theory
A theory in science is an interrelated set of concepts that is used to explain a body of data and to make predictions about the results of future experiments. Currently viable theories are those that have had many of their hypotheses confirmed. The theoretical structures of such theories are, thus, consistent with a large number of observations. However, when the database begins to contradict the hypotheses derived from a theory, scientists begin trying to construct a new theory (or, more often, simply make adjustments in the previous theory) that will provide a better interpretation of the data. Thus, the theories that are under scientific discussion are those that have been verified to some extent and that do not make many predictions that are contradicted by the available data. They are not mere guesses or hunches.
ESP and falsifiability
As a lecturer and public speaker on psychological topics, I am often confronted by people who ask me why I have not lectured on all the startling new discoveries in extrasensory perception (ESP) and parapsychology that have been made in the past few years. I have to inform these questioners that most of what they have heard about these subjects has undoubtedly come from the general media rather than from scientifically respectable sources. In fact, some scientists have looked at these claims and have not been able to replicate the findings. I remind the audience that replication of a finding is critical to its acceptance as an established scientific fact and that this is particularly true in the case of results that contradict either previous data or established theory. I further admit that many scientists have lost patience with ESP research. Although one reason is undoubtedly that the area is tainted by fraud, charlatanism, and media exploitation, perhaps the most important reason for scientific disenchantment is the existence of what science writer Martin Gardner years ago called the catch-22 of ESP research. It works as follows: A "believer" (someone who believes in the existence of ESP phenomena before beginning an investigation) claims to have demonstrated ESP in the laboratory. A "skeptic" (someone who doubts the existence of ESP) is brought in to confirm the phenomena. Often, after observing the experimental situation, the skeptic calls for more controls, and though these are sometimes resisted, well-intentioned believers often agree to them. When the controls are instituted, the phenomena cannot be demonstrated. The skeptic, who correctly interprets this failure as an indication that the original demonstration was due to inadequate experimental control and, thus, cannot be accepted, is often shocked to find that the believer does not regard the original demonstration as invalid. Instead, the believer invokes the catch-22 of ESP: Psychic powers, the believer maintains, are subtle, delicate, and easily disturbed. The "negative vibes" of the skeptic were probably responsible for the disruption of the "psi powers." The believer thinks that the powers will undoubtedly return when the negative aura of the skeptic is removed. This way of interpreting failures to demonstrate ESP in experiments is logically analogous to my story about the little green men. ESP operates just as the little green men do. It's there as long as you don't intrude to look at it carefully. When you do, it disappears. If we accept this explanation, it will be impossible to demonstrate the phenomenon to any skeptical observers. It appears only to believers. Of course, this position is unacceptable in science. We do not have the magnetism physicists and the nonmagnetism physicists (those for whom magnetism does and does not "work"). Interpreting ESP experiments in this way makes the hypothesis of ESP unfalsifiable just as the hypothesis of the little green men is. Interpreting the outcomes in this way puts it outside the realm of science.
Tourette syndrome and falsifiability
As another example, consider the history of Gilles de la Tourette syndrome. This is a disorder characterized by physical tics and twitches that may involve any part of the body, as well as vocal symptoms such as grunts and barks, echolalia (involuntary repetition of the words of others), and coprolalia (compulsive repetition of obscene words). Tourette syndrome is an organically based disorder of the central nervous system and is now often successfully treated with drug therapies. Importantly, understanding of the cause and treatment of the disorder was considerably hampered from 1921 to 1955, when explanations and treatments for Tourette syndrome were dominated by psychoanalytic conceptualizations. Author after author presented unfalsifiable psychoanalytic explanations for the syndrome. The resulting array of vague explanations created a conceptual sludge that obscured the true nature of the syndrome and probably impeded scientific progress toward an accurate understanding of it. Progress in the treatment and understanding of Tourette syndrome began to occur only when researchers recognized that the psychoanalytic "explanations" were useless. These explanations were enticing because they seemed to explain things. In fact, they explained everything—after the fact. However, the explanations they provided created only the illusion of understanding. By attempting to explain everything after the fact, they barred the door to any advancement. Progress occurs only when a theory does not predict everything but instead makes specific predictions that tell us—in advance—something specific about the world. The predictions derived from such a theory may be wrong, of course, but this is a strength, not a weakness.
What do mistake, error, and falsified mean?
Asimov's example of the shape of the earth illustrates for us the context in which scientists use such terms as "mistake," "error," or "falsified." Such terms do not mean that the theory being tested is wrong in every respect, only that it is incomplete. So when scientists emphasize that knowledge is tentative and may be altered by future findings, they are referring to a situation such as this example. When scientists believed that the earth was a sphere, they realized that, in detail, this theory might someday need to be altered. However, the alteration from spherical to oblate spheroidal preserves the "roughly correct" notion that the earth is a sphere. We do not expect to wake up one day and find that it is a cube!
Why do people try to convince the public that psychology cannot be a science?
Attempts to convince the public that psychology cannot be a science stem from a variety of sources. For example, there currently exist many industries surrounding pseudoscientific belief systems that have a vested interest in convincing the public that anything goes in psychology and that there are no rational criteria for evaluating psychological claims. This is the perfect atmosphere in which to market claims like: "Lose weight through hypnosis," "Develop your hidden psychic powers," and "Learn French while you sleep," along with the many other parts of the multibillion-dollar self-help industry that either are not based on scientific evidence or, in many cases, are actually contradicted by much available evidence. Another source of resistance to scientific psychology stems from the tendency to oppose the expansion of science into areas where unquestioned authorities and "common sense" have long reigned. History provides many examples of initial public resistance to the use of science rather than philosophical speculation, theological edict, or folk wisdom to explain the natural world. Each science has gone through a phase of resistance to its development. Each scientific step to greater knowledge about human beings has evoked opposition. This opposition eventually dissipated, however, when people came to realize that science does not destroy the meaning of our lives but enhances it.
Autism and falsifiability
But the existence of such unfalsifiable theories does real damage. For example, explanations for the cause of autism (in part a genetically determined disorder) were led down a blind alley by psychoanalytic explanations for the condition. Influenced by psychoanalytic ideas, psychologist Bruno Bettelheim popularized the now-discredited notion of "refrigerator mothers" as the cause and thought that "the precipitating factor in infantile autism is the parent's wish that his child should not exist". Ideas like this not only did damage, but they set back the study of autism.
Publicly Verifiable Knowledge
By publicly verifiable knowledge, then, we mean findings presented to the scientific community in such a way that they can be replicated, criticized, or extended by anyone in the community. This is a most important criterion not only for scientists but also for the layperson, who, as a consumer, must evaluate scientific information presented in the media. One important way to distinguish charlatans and practitioners of pseudoscience from legitimate scientists is that the former often bypass the normal channels of scientific publication and instead go straight to the media with their "findings." One ironclad criterion that will always work for the public when presented with scientific claims of uncertain validity is the question, Have the findings been published in a recognized scientific journal that uses some type of peer review procedure? The answer to this question will almost always separate pseudoscientific claims from the real thing.
Not all confirmations are equal
Confirmations are more or less impressive depending on the extent to which the prediction exposes itself to potential disconfirmation. One confirmation of a highly specific, potentially falsifiable prediction (for instance, a female, 30 years old, 5 feet 2 inches tall, carrying a book and a purse in the left hand and knocking with the right) has a greater impact than the confirmation of 20 different predictions that are all virtually unfalsifiable (for instance, a person less than 100 years old). Thus, we must look not only at the quantity of the confirming evidence, but also at the quality of the confirming instances. Using the falsifiability criterion as a tool to evaluate evidence will help the research consumer resist the allure of the nonscientific, all-explaining theory that inevitably hinders the search for deeper understanding. Indeed, such theoretical dead ends are often tempting precisely because they can never be falsified. They are islands of stability in the chaotic modern world. Popper often made the point that "the secret of the enormous psychological appeal of these unfalsifiable theories lies in their ability to explain everything. To know in advance that whatever happens you will be able to understand it gives you not only a sense of intellectual mastery but, even more important, an emotional sense of secure orientation in the world". However, the attainment of such security is not the goal of science, because such security would be purchased at the cost of intellectual stagnation. Science is a mechanism for continually challenging previously held beliefs by subjecting them to empirical tests in such a way that they can be shown to be wrong. This characteristic often puts science—particularly psychology—in conflict with so-called folk wisdom or common sense.
Systematic Empiricism
Empiricism: the practice of relying on observation. Scientists find out about the world by examining it. The empirical approach is not necessarily obvious, which is why we often have to teach it, even in a society that is dominated by science. Empiricism pure and simple is not enough, however. Note that the heading for this section is "Systematic Empiricism." Observation is fine and necessary, but pure, unstructured observation of the natural world will not lead to scientific knowledge. Write down every observation you make from the time you get up in the morning to the time you go to bed on a given day. When you finish, you will have a great number of facts, but you will not have a greater understanding of the world. Scientific observation is termed systematic because it is structured so that the results of the observation reveal something about the underlying nature of the world. Scientific observations are usually theory driven; they test different explanations of the nature of the world. They are structured so that, depending on the outcome of the observation, some theories are supported and others rejected.
Defining what science is not
First, science is not defined by subject matter. Any aspect of the universe is fair game for the development of a scientific discipline, including all aspects of human behavior. We cannot divide the universe into "scientific" and "nonscientific" topics. Although strong forces throughout history have tried to place human beings outside the sphere of scientific investigation, they have been unsuccessful, as we shall see. The reactions against psychology as a scientific discipline probably represent the modern remnants of this ancient struggle. Science is also not defined by the presence of instruments and experimental apparatus. It is not the test tube, the computer, the electronic equipment, or the investigator's white coat that defines science. These are the trappings of science but are not its defining features. Science is, rather, a way of thinking about and observing the universe that leads to a deep understanding of its workings.
Good Theories
Good theories, then, make predictions that expose themselves to falsification. Bad theories do not put themselves in jeopardy in this way. They make predictions that are so general that they are almost bound to be true (e.g., the next person to knock on my door will be less than 100 years old) or are phrased in such a way that they are completely protected from falsification (as in the Benjamin Rush example). In fact, a theory can be so protected from falsifiability that it is simply no longer considered scientific at all. Indeed, it was philosopher Karl Popper's attempt to define the criteria that separate science from nonscience that led him to emphasize the importance of the falsifiability principle.
Hypothesis
Hypotheses are specific predictions that are derived from theories (which are more general and comprehensive).
Freud and Falsifiability
In the early decades of the twentieth century, Popper was searching for the underlying reasons that some scientific theories seem to lead to advances in knowledge and others lead to intellectual stagnation. Einstein's general relativity theory, for example, led to startlingly new observations (for instance, that the light from a distant star bends when it passes near the sun) precisely because its predictions were structured so that many possible events could have contradicted them and, thus, falsified the theory. Popper reasoned that this is not true of stagnant theories—and pointed to Freudian psychoanalysis as an example. Freudian theory uses a complicated conceptual structure that explains human behavior after the fact—that is, after it has occurred—but does not predict things in advance. In short, Freudian theory can explain everything. However, as Popper argued, it is precisely this property that makes it scientifically useless. It makes no specific predictions. Adherents of psychoanalytic theory spend much time and effort in getting the theory to explain every known human event, from individual quirks of behavior to large-scale social phenomena. But their success in making the theory a rich source of after-the-fact explanation robs it of any scientific utility. Freudian psychoanalytic theory currently plays a much larger role as a spur to the literary imagination than as a theory in contemporary psychology. Its demise within psychology can be traced in part to its failure to satisfy the falsifiability criterion.
New Theory vs Old Theory
It should also be emphasized that, when scientists talk about falsifying a theory based on observation and about replacing an old, falsified theory with a new one, they do not mean that all the previous facts that established the old theory are thrown out. Quite the contrary, the new theory must explain all of the facts that the old theory could explain plus the new facts that the old theory could not explain. So the falsification of a theory does not mean that scientists have to go back to square one. Complex theories can be generally right without being perfectly right, and beliefs can be getting closer to the truth without being exactly true.
Unity in Science
Many sciences are dedicated to understanding people. Many professions are dedicated to helping people. There are only two things that justify psychology as an independent discipline: 1. Psychology studies the full range of human and nonhuman behavior with the techniques of science 2. The applications that derive from this knowledge are scientifically based. Two guarantees given to the public by psychology: 1. The conclusions about behavior that it produces derive from scientific evidence. 2. Practical applications of psychology have been derived from and tested by scientific methods. Psychology is a data-based scientific study of behavior.
Scientific Laws
Of course, saying that knowledge in science is tentative and that hypotheses derived from theories are potentially false does not mean that everything is up for grabs. There are many relationships in science that have been confirmed so many times that they are termed laws because it is extremely doubtful that they will be overturned by future experimentation. It is highly unlikely that we shall find one day that blood does not circulate in the veins and arteries or that the earth does not orbit the sun. These mundane facts are not the type of hypotheses that we have been talking about. They are of no interest to scientists precisely because they are so well established. Scientists are interested only in those aspects of nature that are on the fringes of what is known. They are not interested in things that are so well confirmed that there is no doubt about them.
Psychology and Folk Wisdom: The Problem with Common Sense
Our personal models of behavior are not really coherent in the way that an actual theory would have to be. Instead, we carry around a ragbag of general principles, homilies, and clichés about human behavior that we draw on when we feel that we need an explanation. The problem with this commonsense knowledge, this folk wisdom, is that much of it contradicts itself and is, therefore, unfalsifiable. The enormous appeal of clichés like these is that, taken together as implicit "explanations" of behavior, they cannot be refuted. No matter what happens, one of these explanations will be cited to cover it. No wonder we all think we are such excellent judges of human behavior and personality. Our folk wisdom gives us an explanation for anything and everything that happens. As such, folk wisdom is cowardly in the sense that it takes no risk that it might be refuted. Folk wisdom is "after the fact" wisdom, but it's actually useless in a predictive sense. A further problem occurs even in cases in which our folk beliefs do have some specificity; that is, even when they are empirically testable. The problem is that psychological research has shown that, when many common cultural beliefs about behavior are subjected to empirical test, they turn out to be false. Common folk beliefs that are falsifiable often turn out to be wrong. Children who read a lot and are academically inclined are actually also more physically and socially robust. Aggression is actually linked with high self esteem, not low self esteem. It isn't true that we only use 10% of our brains. And people aren't just left brained or right brained. New folk myths are being created, like the belief that the technology native millennials are able to multitask without losing efficiency. However, they are no better at multitasking than anyone else. Beliefs about us all being intelligent in our own ways are incorrect as are beliefs that we can speed read without losing comprehension. These problems with folk psychology would not be so damaging if people realized the fallibility of their folk beliefs. Instead, however, surveys have shown that over 80 percent of the public thinks that adequate training in psychology is provided by daily life! To the contrary, we need the discipline of psychology because it provides tests of the empirical basis of common sense. Sometimes common sense beliefs do not hold up when tested, as we saw in many of the previous examples. From the examples discussed—and many more could be cited—we can see that psychology's role as the empirical tester of much folk wisdom often brings it into conflict with many widely held cultural beliefs. Psychology is often the bearer of the "bad tidings" that comfortable folk beliefs do not stand up to the cold light of day. Perhaps it is not surprising that many people would like not only to ignore the message but also to do away with the messenger.
Peer Review
Peer review is a procedure in which each paper submitted to a research journal is critiqued by several scientists, who then submit their criticisms to an editor. The editor is usually a scientist with an extensive history of work in the specialty area covered by the journal. The editor decides whether the weight of opinion warrants publication of the paper, publication after further experimentation and statistical analysis, or rejection because the research is flawed or trivial. Legitimate journals publish statements of their editorial policies in each issue and on their websites, so you should always check to see whether a journal is peer reviewed. This is even more important now because the web has spawned dozens of open-access journals that will publish anything for a fee. These vanity web journals prey on young scholars desperate to publish in order to get tenure at universities. Their presence on the web makes it harder for the general public to discern peer-reviewed scientific research from things on the web that look scientific but have not undergone the scrutiny of peer review. Not all information in peer-reviewed scientific journals is necessarily correct, but at least it has met a criterion of peer criticism and scrutiny. Peer review is a minimal criterion, not a stringent one, because most scientific disciplines publish dozens of different journals of varying quality. Most scientific ideas can get published somewhere in the legitimate literature if they meet some rudimentary standards. The idea that only a narrow range of data and theory can get published in science is false. This is an idea often suggested by purveyors of bogus remedies and therapies who try to convince the media and the public that they have been shut out of scientific outlets by a conspiracy of "orthodox science." But consider for a minute just how many legitimate outlets there are in a field like psychology. The APA database PsycINFO summarizes articles from over 2,000 different journals. Most of these journals are peer reviewed. Virtually all halfway legitimate theories and experiments can find their way into this vast array of publication outlets. Indeed, if anything, there are probably too many scientific journals. And there are certainly too many non-peer-reviewed journals and vanity journals that are not reviewed at all. The mechanisms of peer review vary somewhat from discipline to discipline, but the underlying rationale is the same. Peer review is one way that science institutionalizes the attitudes of objectivity and public criticism (replication is another). Ideas and experimentation undergo a honing process in which they are submitted to other critical minds for evaluation. Ideas that survive this critical process have begun to meet the criterion of public verifiability. The peer review process is far from perfect, but it is really the only consumer protection that we have.
Implications of diversity
Psychology doesn't have one grand all encompassing theory. It has many different theories, each covering a limited aspect of behavior. The diversity of psychology guarantees that the task of theoretical unification will be immensely difficult. Evolutionary psychologists have been researching to try to bring unification to our conceptualization of human psychological processes by viewing them as mechanisms serving critical evolutionary functions. Many university departments are changing their name to "Department of Psychological Sciences." With the plural term conveying the diversity of content in the discipline.
Falsifiability and Folk Wisdom
Psychology is a threat to the comfort that folk wisdom provides because, as a science, it cannot be content with explanations that cannot be refuted. The goal of psychology is the empirical testing of alternative behavioral theories in order to rule out some of them. Aspects of folk wisdom that are explicitly stated and that do stand up to empirical testing are, of course, welcomed, and many have been incorporated into psychological theory. However, psychology does not seek the comfort of explanatory systems that account for everything after the fact but predict nothing in advance. It does not accept systems of folk wisdom that are designed never to be changed and that end up being passed on from generation to generation. It is self-defeating to try to hide this fact from students or the public. Unfortunately, some psychology instructors and popularizers are aware that psychology's threat to folk wisdom disturbs some people, and they sometimes seek to soothe such feelings by sending a false underlying message that implies, "You'll learn some interesting things, but don't worry—psychology won't challenge things you believe in strongly." This is a mistake, and it contributes to confusion both about what science is and about what psychology is. Psychology establishes facts about sexual behavior, intelligence, crime, financial behavior, the effects of marriage, child rearing, and many other topics that people feel strongly about. It would be amazing if the investigation of subjects such as these failed to uncover something that did not upset somebody! Science seeks conceptual change. Scientists try to describe the world as it really is, as opposed to what our prior beliefs dictate it should be. The dangerous trend in modern thought is the idea that people must be shielded from the nature of the world—that a veil of ignorance is necessary to protect a public unequipped to deal with the truth. Psychology is like other sciences in rejecting the idea that people need to be shielded from findings that make them uncomfortable. Psychology is not a "safe space" for those who want their beliefs to go unchallenged by evidence
The diversity of modern psychology
Psychology stretches from biological to social sciences. The APA has 54 different divisions with other smaller subdivisions.
Psychology as a young science
Psychology's battle to establish its problems as empirically solvable has only recently been won. But as the science progresses, psychologists will address more and more issues that are the subject of strongly held beliefs about human beings because many of these problems are empirically testable. Some people object to empirical investigation in some areas; yet there has been scientific progress in each one of them. Finally, people often are offended simply by the presentation of simple descriptive facts about human behavior. For example, it is enough to offend some people to just report the simple fact that children growing up in single-parent households are more likely to experience poverty and behavioral problems. This is the type of opposition to simple empirical facts about human behavior that psychology has to deal with on a regular basis. This opposition, when the issue is a heated one, can get hostile and can be personally directed at psychologists. There are subgroups in the population who do not like many of the findings coming out of scientific psychology, including, for example, that intelligence is partially heritable; that there are evolutionary explanations for some of our sexual behaviors; and that there are cognitive biases that lead us to believe in pseudoscience and conspiracy theories. Psychology is often in a no-win situation as a discipline. On the one hand, some people object to calling psychology a science and deny that psychologists can establish empirical facts about behavior. On the other hand, there are those who object to the investigation of certain areas of human behavior because they fear that the facts uncovered by psychology might threaten their beliefs. Skinnerian psychologists regularly deal with these contradictory criticisms. For instance, critics have argued that the laws of reinforcement formulated by behaviorists do not apply to human behavior. At the same time, other critics are concerned that the laws will be used for the rigid and inhumane control of people. Thus, the behaviorists are faced with some critics who deny that their laws can be applied and others who charge that their laws can be applied all too easily! Examples such as this arise because the relatively new science of psychology has just begun to uncover facts about aspects of behavior that have previously escaped study. The relative youth of psychology as a science partially explains why many people are confused about the discipline. Nevertheless, during the past several decades, psychology has become firmly established in the interconnecting structure of knowledge that we call science. Failure to appreciate this fact is the source of almost all of the confused thinking about psychology that you will encounter.
Empirically Solvable Problems: Scientists' Search for Testable Theories
Science deals with solvable, or specifiable, problems. This means that the types of questions that scientists address are potentially answerable by means of currently available empirical techniques. If a problem is not solvable or a theory is not testable by the empirical techniques that scientists have at hand, then scientists will not attack it. Science advances by positing theories to account for particular phenomena in the world, by deriving predictions from these theories, by testing the predictions empirically, and by modifying the theories based on the tests. The sequence might be portrayed as follows: theory → prediction → test → theory modification. So what a scientist often means by the term solvable problem is "testable theory." What makes a theory testable? The theory must have specific implications for observable events in the natural world; this is what is meant by empirically testable. This criterion of testability is often called the falsifiability criterion. Psychology itself provides many good examples of the development from the unsolvable to the solvable. There are many questions (such as "How does a child acquire the language of his or her parents?", "Why do we forget things we once knew?", or "How does being in a group change a person's behavior and thinking?") that had been the subjects of philosophical speculation for centuries before anyone recognized that they could be addressed by empirical means. As this recognition slowly developed, psychology coalesced as a collection of problems concerning behavior in a variety of domains. Psychological issues gradually became separated from philosophy, and a separate empirical discipline evolved. Cognitive psychologist Steven Pinker (1997) discusses how ignorance can be divided into problems and mysteries. In the case of problems, we know that an answer is possible and what that answer might look like even though we might not actually have the answer yet. In the case of mysteries, we can't even conceive of what an answer might look like. Using this terminology, we can see that science is a process that turns mysteries into problems.
Publicly Verifiable Knowledge: Replication and Peer Review
Scientific knowledge is public in a special sense. By public, we, of course, do not mean that scientific observations are posted on community center bulletin boards. Instead, we refer to the fact that scientific knowledge does not exist solely in the mind of a particular individual. In an important sense, scientific knowledge does not exist at all until it has been submitted to the scientific community for criticism and empirical testing by others. Knowledge that is considered "special"—the province of the thought processes of a particular individual, immune from scrutiny and criticism by others—can never have the status of scientific knowledge. Likewise, science rejects the claim that particular groups have access to special knowledge. Science makes the idea of public verifiability concrete via the procedure of replication. In order to be considered in the realm of science, a finding must be presented to the scientific community in a way that enables other scientists to attempt the same experiment and obtain the same results. When this occurs, we say that the finding has been replicated. Scientists use replication to define the idea of public knowledge. Replication ensures that a particular finding is not due simply to the errors or biases of a particular investigator. In short, for a finding to be accepted by the scientific community, it must be possible for someone other than the original investigator to duplicate it. When a finding is presented in this way, it becomes public. It is no longer the sole possession of the original researcher; it is instead available for other investigators to extend, criticize, or apply in their own ways.
Falsifiability Criterion
Scientific theories must always be stated in such a way that the predictions derived from them could potentially be shown to be false. Thus, the methods of evaluating new evidence relevant to a particular theory must always include the possibility that the data will falsify the theory. This principle is often termed the falsifiability criterion, and its importance in scientific progress has been most forcefully articulated by Karl Popper, a philosopher of science whose writings are read widely by working scientists. The falsifiability criterion states that, for a theory to be useful, the predictions drawn from it must be specific. The theory must go out on a limb, so to speak, because in telling us what should happen, the theory must also imply that certain things will not happen. If these latter things do happen, then we have a clear signal that something is wrong with the theory: It may need to be modified, or we may need to look for an entirely new theory. Either way, we will end up with a theory that is nearer to the truth. By contrast, if a theory does not rule out any possible observations, then the theory can never be changed, and we are frozen into our current way of thinking, with no possibility of progress. Thus, a successful theory is not one that accounts for every possible outcome because such a theory robs itself of any predictive power. As biologist Stuart Firestein puts it, we should have confidence in science not because it is always right, but instead because it is possible to prove it wrong.
The freedom to admit a mistake
Scientists have found that one of the most liberating and useful implications of the falsifiability principle is that, in science, making a mistake is not a sin. By the process of continually adjusting theory when data do not accord with it, scientists collectively arrive at theories that better reflect the nature of the world. Biologist Stuart Firestein writes that the usual list of the pillars of science—things like reason and fact and truth and experiment and objectivity—usually have one critical pillar missing. That pillar that we often forget, Firestein suggests, is failure. By failure, Firestein means making errors that we learn something from. He mean errors in the Popperian sense. Indeed, Firestein calls Popper the philosopher of failure. In fact, our way of operating in everyday life might be greatly improved if we could use the falsifiability principle on a personal level. This is why the word liberating was used in the opening sentence of this section. It has a personal connotation that was specifically intended—because the ideas developed here have implications beyond science. We would have many fewer social and personal problems if we could only understand that, when our beliefs are contradicted by evidence in the world, it is better to adjust our beliefs than to deny the evidence and cling tenaciously to dysfunctional ideas. Many scientists have attested to the importance of understanding that making errors in the course of science is normal and that the real danger to scientific progress is our natural human tendency to avoid exposing our beliefs to situations in which they might be shown to be wrong. Scientists must avoid this tendency, and Nobel Prize winner Peter Medawar urged them to avoid it by remembering that "the intensity of the conviction that a hypothesis is true has no bearing on whether it is true or not" But the falsifying attitude doesn't always have to characterize each and every scientist for science to work. The unique power of science to reveal knowledge about the world does not arise because scientists are uniquely virtuous (that they are completely objective; that they are never biased in interpreting findings, etc.) but instead it arises because fallible scientists are immersed in a process of checks and balances—in a process in which other scientists are always there to criticize and to root out the errors of their peers. The strength of science comes not because scientists are especially virtuous, but from a social process where scientists constantly cross-check each others' knowledge and conclusions.
Layperson vs Scientific Theory
The difference between the layperson's and the scientist's use of the word theory has often been exploited by people who want creationism taught in the public schools. Their argument often is "After all, evolution is only a theory." This statement is intended to suggest the layperson's use of the term theory. In common language, the term theory means "only a guess." However, the theory of evolution by natural selection is not a theory in the layperson's sense (to the contrary, in the layperson's sense, it would be called a fact). Instead, it is a theory in the scientific sense. It is a conceptual structure that is supported by a large and varied set of data. It is not a mere guess, equal to any other guess. Instead, it interlocks with knowledge in a host of other disciplines, including geology, physics, chemistry, and all aspects of biology.
The Freud Problem
The general public's beliefs about psychology are largely influenced by what they know of Sigmund Freud. But his work made very few contributions to modern psychology, and only about 5% of psychologists have anything to do with his methods of psychoanalysis today. Freuds methods of investigation don't represent how psychological research is actually conducted. Freud didn't use controlled experimentation and depended largely on case studies to establish the truth or falsity of theories. He had a lot of theories and hypotheses, but he lacked a method of empirical observation. Freud's theories don't meet the minimal requirements for a link between the theory and behavioral data. Familiarity with Freud's style of work can be a significant impediment to the understanding of modern psychology.
How do scientists make sure they are dealing with testable theories?
The way scientists make sure they are dealing with testable theories is by ensuring that their theories are falsifiable, that is, that they have implications for actual events in the natural world. Scientific theories must always be stated in such a way that the predictions derived from them could potentially be shown to be false.
Some thoughts are cheap
These theories, usually described in several pages of single-spaced typescript, are speculations about the deepest ultimate questions we can ask—what is the nature of life? the origin of the universe? the beginning of time? But thoughts are cheap. Any person of intelligence can devise his half dozen before breakfast. Scientists can also spin out ideas about ultimates. We don't (or, rather, we confine them to our private thoughts) because we cannot devise ways to test them, to decide whether they are right or wrong. What good to science is a lovely idea that cannot, as a matter of principle, ever be affirmed or denied? Gould was telling us that such theories are useless for scientific purposes, however comforting they may be. Science is a creative endeavor, but the creativity involves getting conceptual structures to fit the confines of empirical data. This is tough. These types of thoughts—those that explain the world as it actually is—are not cheap. Probably this is why good scientific theories are so hard to come by and why unfalsifiable pseudoscientific belief systems proliferate everywhere—the latter are vastly easier to construct. In fact, they are so easy to construct that there is an event—the Festival of Bad Ad-Hoc Hypotheses (BAH-Fest)—that gives an award for presenting the most creative theory that is made unfalsifiable by ad hoc assumptions and caveats. One reason that constructing unfalsifiable theories is easy is that one sure-fire way to prevent a theory from being falsified is to fill it with obfuscation and incomprehensible jargon. Many unfalsifiable conspiracy theories (e.g., that the government has spread AIDS deliberately, or that it knew of the 9/11 attacks in advance) have this property. This is the reason that belief in conspiracy theories tends to correlate—if a person believes in one, they tend to believe in another. There seems to be a general tendency to be entranced by unfalsifiable obfuscation.
Scientific uncertainty on fringes of knowledge
This aspect of scientific practice—that scientists gravitate to those problems on the fringes of what is known and ignore things that are well confirmed (so-called laws)—is very confusing to the general public. It seems that scientists are always emphasizing what they don't know rather than what is known. This is true, and there is a very good reason for it. To advance knowledge, scientists must be at the outer limits of what is known. Of course, this is precisely where things are uncertain. But science advances by a process of trying to reduce the uncertainty at the limits of knowledge. This can often make scientists look "uncertain" to the public. But this perception is deceiving. Scientists are only uncertain at the fringes of knowledge—where our understanding is currently being advanced. Scientists are not uncertain about the many facts that have been well established by replicable research.
Myside bias
This social cross-checking is a really distinctive feature of science as a domain. Yes, the value of objectivity is often invoked by many people in other domains of life. But no other domain of life has such structured cross-checking built in like science. Instead, in other domains of life, myside bias reigns supreme. Myside bias is the tendency for people to evaluate evidence, generate evidence, and test hypotheses in a manner biased toward their own prior beliefs, opinions and attitudes. Myside bias is common in the domain of politics. For example, liberals routinely admonish conservatives for failing to acknowledge the strong evidence that human activity is a contributor to global warming. They are right to do so because the evidence for this conclusion is highly convergent. But what most liberals fail to realize is that they have fallen prey to myside bias by cherry-picking the issue of climate change. They have focused on an issue where it is easy for liberals to agree with the scientific conclusion and hard for conservatives to agree with the conclusion. What liberals goading conservatives about climate change do not seem to realize is how easily the situation could be cherry-picked in the other direction. They don't realize how easy it would be for conservatives to ask liberals to accept the scientific evidence for conclusions that make liberals uncomfortable—that intelligence is at least moderately heritable for example, or that women do not in fact make 20 percent less than a man makes for doing the same job. Both liberals and conservatives are guilty of myside bias. That is why we need science—for its process, not for its individuals. The latter are no more unbiased than anyone else, but they are immersed in a process of error detection and cross-checking that is relatively unique.
The Theory of Knocking Rhythms
Why the difference in my reactions? Why do my friend's three predictions yield three different responses, ranging from "So what?" to "Wow!"? The answer has to do with the specificity and precision of the predictions. The more specific predictions made a greater impact when they were confirmed. Notice, however, that the specificity varied directly with the falsifiability. The more specific and precise the prediction was, the more potential observations there were that could have falsified it. For example, there are a lot of people who are not 30-year-old females and 5 feet 2 inches tall. Note that implicitly, by my varied reactions, I signaled that I would be more impressed by a theory that made predictions that maximized the number of events that should not occur.
Defining what science is
three important and interrelated features that define science: (1) the use of systematic empiricism; (2) the production of public knowledge; and (3) the examination of solvable problems.
