Chapter 1: THE NATURE OF SCIENCE
THE SCIENTIFIC WORLD VIEW
THE SCIENTIFIC ENTERPRISE
Chapter 1: THE NATURE OF SCIENCE
Over the course of human history, people have developedmany interconnected and validated ideas about the physical,biological, psychological, and social worlds. Those ideas haveenabled successive generations to achieve an increasinglycomprehensive and reliable understanding of the human species andits environment. The means used to develop these ideas areparticular ways of observing, thinking, experimenting, andvalidating. These ways represent a fundamental aspect of thenature of science and reflect how science tends to differ fromother modes of knowing.
It is the union of science, mathematics, and technologythat forms the scientific endeavor and that makes it sosuccessful. Although each of these human enterprises has acharacter and history of its own, each is dependent on andreinforces the others. Accordingly, the first three chapters ofrecommendations draw portraits of science, mathematics, andtechnology that emphasize their roles in the scientific endeavorand reveal some of the similarities and connections amongthem.
This chapter lays out recommendations for what knowledge ofthe way science works is requisite for scientific literacy. Thechapter focuses on three principal subjects: the scientific worldview, scientific methods of inquiry, and the nature of thescientific enterprise. Chapters 2 and 3 consider ways in whichmathematics and technology differ from science in general.Chapters 4 through 9 present views of the world as depicted bycurrent science; Chapter 10, Historical Perspectives, covers keyepisodes in the development of science; and Chapter 11, CommonThemes, pulls together ideas that cut across all these views ofthe world.
THE SCIENTIFIC WORLD VIEW
Scientists share certain basic beliefs and attitudes aboutwhat they do and how they view their work. These have to do withthe nature of the world and what can be learned about it.The World Is Understandable
Science presumes that the things and events in the universeoccur in consistent patterns that are comprehensible throughcareful, systematic study. Scientists believe that through theuse of the intellect, and with the aid of instruments that extendthe senses, people can discover patterns in all of nature.
Science also assumes that the universe is, as its nameimplies, a vast single system in which the basic rules areeverywhere the same. Knowledge gained from studying one part ofthe universe is applicable to other parts. For instance, the sameprinciples of motion and gravitation that explain the motion offalling objects on the surface of the earth also explain themotion of the moon and the planets. With some modifications overthe years, the same principles of motion have applied to otherforcesand to the motion of everything, from the smallestnuclear particles to the most massive stars, from sailboats tospace vehicles, from bullets to light rays.Scientific Ideas Are Subject ToChange
Science is a process for producing knowledge. The processdepends both on making careful observations of phenomena and oninventing theories for making sense out of those observations.Change in knowledge is inevitable because new observations maychallenge prevailing theories. No matter how well one theoryexplains a set of observations, it is possible that anothertheory may fit just as well or better, or may fit a still widerrange of observations. In science, the testing and improving andoccasional discarding of theories, whether new or old, go on allthe time. Scientists assume that even if there is no way tosecure complete and absolute truth, increasingly accurateapproximations can be made to account for the world and how itworks.Scientific Knowledge IsDurable
Although scientists reject the notion of attaining absolutetruth and accept some uncertainty as part of nature, mostscientific knowledge is durable. The modification of ideas,rather than their outright rejection, is the norm in science, aspowerful constructs tend to survive and grow more precise and tobecome widely accepted. For example, in formulating the theory ofrelativity, Albert Einstein did not discard the Newtonian laws ofmotion but rather showed them to be only an approximation oflimited application within a more general concept. (The NationalAeronautics and Space Administration uses Newtonian mechanics,for instance, in calculating satellite trajectories.) Moreover,the growing ability of scientists to make accurate predictionsabout natural phenomena provides convincing evidence that wereally are gaining in our understanding of how the world works.Continuity and stability are as characteristic of science aschange is, and confidence is as prevalent as tentativeness.Science Cannot Provide CompleteAnswers to All Questions
There are many matters that cannot usefully be examined in ascientific way. There are, for instance, beliefs thatbytheir very naturecannot be proved or disproved (such as theexistence of supernatural powers and beings, or the true purposesof life). In other cases, a scientific approach that may be validis likely to be rejected as irrelevant by people who hold tocertain beliefs (such as in miracles, fortune-telling, astrology,and superstition). Nor do scientists have the means to settleissues concerning good and evil, although they can sometimescontribute to the discussion of such issues by identifying thelikely consequences of particular actions, which may be helpfulin weighing alternatives.
Fundamentally, the various scientific disciplines are alike intheir reliance on evidence, the use of hypothesis and theories,the kinds of logic used, and much more. Nevertheless, scientistsdiffer greatly from one another in what phenomena theyinvestigate and in how they go about their work; in the reliancethey place on historical data or on experimental findings and onqualitative or quantitative methods; in their recourse tofundamental principles; and in how much they draw on the findingsof other sciences. Still, the exchange of techniques,information, and concepts goes on all the time among scientists,and there are common understandings among them about whatconstitutes an investigation that is scientifically valid.
Scientific inquiry is not easily described apart from thecontext of particular investigations. There simply is no fixedset of steps that scientists always follow, no one path thatleads them unerringly to scientific knowledge. There are,however, certain features of science that give it a distinctivecharacter as a mode of inquiry. Although those features areespecially characteristic of the work of professional scientists,everyone can exercise them in thinking scientifically about manymatters of interest in everyday life.Science Demands Evidence
Sooner or later, the validity of scientific claims is settledby referring to observations of phenomena. Hence, scientistsconcentrate on getting accurate data. Such evidence is obtainedby observations and measurements taken in situations that rangefrom natural settings (such as a forest) to completely contrivedones (such as the laboratory). To make their observations,scientists use their own senses, instruments (such asmicroscopes) that enhance those senses, and instruments that tapcharacteristics quite different from what humans can sense (suchas magnetic fields). Scientists observe passively (earthquakes,bird migrations), make collections (rocks, shells), and activelyprobe the world (as by boring into the earth"s crust oradministering experimental medicines).
In some circumstances, scientists can control conditionsdeliberately and precisely to obtain their evidence. They may,for example, control the temperature, change the concentration ofchemicals, or choose which organisms mate with which others. Byvarying just one condition at a time, they can hope to identifyits exclusive effects on what happens, uncomplicated by changesin other conditions. Often, however, control of conditions may beimpractical (as in studying stars), or unethical (as in studyingpeople), or likely to distort the natural phenomena (as instudying wild animals in captivity). In such cases, observationshave to be made over a sufficiently wide range of naturallyoccurring conditions to infer what the influence of variousfactors might be. Because of this reliance on evidence, greatvalue is placed on the development of better instruments andtechniques of observation, and the findings of any oneinvestigator or group are usually checked by others.Science Is a Blend of Logic andImagination
Although all sorts of imagination and thought may be used incoming up with hypotheses and theories, sooner or laterscientific arguments must conform to the principles of logicalreasoningthat is, to testing the validity of arguments byapplying certain criteria of inference, demonstration, and commonsense. Scientists may often disagree about the value of aparticular piece of evidence, or about the appropriateness ofparticular assumptions that are madeand therefore disagreeabout what conclusions are justified. But they tend to agreeabout the principles of logical reasoning that connect evidenceand assumptions with conclusions.
Scientists do not work only with data and well-developedtheories. Often, they have only tentative hypotheses about theway things may be. Such hypotheses are widely used in science forchoosing what data to pay attention to and what additional datato seek, and for guiding the interpretation of data. In fact, theprocess of formulating and testing hypotheses is one of the coreactivities of scientists. To be useful, a hypothesis shouldsuggest what evidence would support it and what evidence wouldrefute it. A hypothesis that cannot in principle be put to thetest of evidence may be interesting, but it is not likely to bescientifically useful.
The use of logic and the close examination of evidence arenecessary but not usually sufficient for the advancement ofscience. Scientific concepts do not emerge automatically fromdata or from any amount of analysis alone. Inventing hypothesesor theories to imagine how the world works and then figuring outhow they can be put to the test of reality is as creative aswriting poetry, composing music, or designing skyscrapers.Sometimes discoveries in science are made unexpectedly, even byaccident. But knowledge and creative insight are usually requiredto recognize the meaning of the unexpected. Aspects of data thathave been ignored by one scientist may lead to new discoveries byanother.Science Explains andPredicts
Scientists strive to make sense of observations of phenomenaby constructing explanations for them that use, or are consistentwith, currently accepted scientific principles. Suchexplanationstheoriesmay be either sweeping orrestricted, but they must be logically sound and incorporate asignificant body of scientifically valid observations. Thecredibility of scientific theories often comes from their abilityto show relationships among phenomena that previously seemedunrelated. The theory of moving continents, for example, hasgrown in credibility as it has shown relationships among suchdiverse phenomena as earthquakes, volcanoes, the match betweentypes of fossils on different continents, the shapes ofcontinents, and the contours of the ocean floors.
The essence of science is validation by observation. But it isnot enough for scientific theories to fit only the observationsthat are already known. Theories should also fit additionalobservations that were not used in formulating the theories inthe first place; that is, theories should have predictive power.Demonstrating the predictive power of a theory does notnecessarily require the prediction of events in the future. Thepredictions may be about evidence from the past that has not yetbeen found or studied. A theory about the origins of humanbeings, for example, can be tested by new discoveries ofhuman-like fossil remains. This approach is clearly necessary forreconstructing the events in the history of the earth or of thelife forms on it. It is also necessary for the study of processesthat usually occur very slowly, such as the building of mountainsor the aging of stars. Stars, for example, evolve more slowlythan we can usually observe. Theories of the evolution of stars,however, may predict unsuspected relationships between featuresof starlight that can then be sought in existing collections ofdata about stars.Scientists Try to Identify andAvoid Bias
When faced with a claim that something is true, scientistsrespond by asking what evidence supports it. But scientificevidence can be biased in how the data are interpreted, in therecording or reporting of the data, or even in the choice of whatdata to consider in the first place. Scientists" nationality,sex, ethnic origin, age, political convictions, and so on mayincline them to look for or emphasize one or another kind ofevidence or interpretation. For example, for many years the studyof primatesby male scientistsfocused on thecompetitive social behavior of males. Not until female scientistsentered the field was the importance of female primates"community-building behavior recognized.
Bias attributable to the investigator, the sample, the method,or the instrument may not be completely avoidable in everyinstance, but scientists want to know the possible sources ofbias and how bias is likely to influence evidence. Scientistswant, and are expected, to be as alert to possible bias in theirown work as in that of other scientists, although suchobjectivity is not always achieved. One safeguard againstundetected bias in an area of study is to have many differentinvestigators or groups of investigators working in it.Science Is Not Authoritarian
It is appropriate in science, as elsewhere, to turn toknowledgeable sources of information and opinion, usually peoplewho specialize in relevant disciplines. But esteemed authoritieshave been wrong many times in the history of science. In the longrun, no scientist, however famous or highly placed, is empoweredto decide for other scientists what is true, for none arebelieved by other scientists to have special access to the truth.There are no preestablished conclusions that scientists mustreach on the basis of their investigations.
In the short run, new ideas that do not mesh well withmainstream ideas may encounter vigorous criticism, and scientistsinvestigating such ideas may have difficulty obtaining supportfor their research. Indeed, challenges to new ideas are thelegitimate business of science in building valid knowledge. Eventhe most prestigious scientists have occasionally refused toaccept new theories despite there being enough accumulatedevidence to convince others. In the long run, however, theoriesare judged by their results: When someone comes up with a new orimproved version that explains more phenomena or answers moreimportant questions than the previous version, the new oneeventually takes its place.
THE SCIENTIFIC ENTERPRISE
Science as an enterprise has individual, social, andinstitutional dimensions. Scientific activity is one of the mainfeatures of the contemporary world and, perhaps more than anyother, distinguishes our times from earlier centuries.Science Is a Complex SocialActivity
Scientific work involves many individuals doing many differentkinds of work and goes on to some degree in all nations of theworld. Men and women of all ethnic and national backgroundsparticipate in science and its applications. Thesepeoplescientists and engineers, mathematicians, physicians,technicians, computer programmers, librarians, andothersmay focus on scientific knowledge either for its ownsake or for a particular practical purpose, and they may beconcerned with data gathering, theory building, instrumentbuilding, or communicating.
As a social activity, science inevitably reflects socialvalues and viewpoints. The history of economic theory, forexample, has paralleled the development of ideas of socialjusticeat one time, economists considered the optimum wagefor workers to be no more than what would just barely allow theworkers to survive. Before the twentieth century, and well intoit, women and people of color were essentially excluded from mostof science by restrictions on their education and employmentopportunities; the remarkable few who overcame those obstacleswere even then likely to have their work belittled by the scienceestablishment.
The direction of scientific research is affected by informalinfluences within the culture of science itself, such asprevailing opinion on what questions are most interesting or whatmethods of investigation are most likely to be fruitful.Elaborate processes involving scientists themselves have beendeveloped to decide which research proposals receive funding, andcommittees of scientists regularly review progress in variousdisciplines to recommend general priorities for funding.
Science goes on in many different settings. Scientists areemployed by universities, hospitals, business and industry,government, independent research organizations, and scientificassociations. They may work alone, in small groups, or as membersof large research teams. Their places of work include classrooms,offices, laboratories, and natural field settings from space tothe bottom of the sea.
Because of the social nature of science, the dissemination ofscientific information is crucial to its progress. Somescientists present their findings and theories in papers that aredelivered at meetings or published in scientific journals. Thosepapers enable scientists to inform others about their work, toexpose their ideas to criticism by other scientists, and, ofcourse, to stay abreast of scientific developments around theworld. The advancement of information science (knowledge of thenature of information and its manipulation) and the developmentof information technologies (especially computer systems) affectall sciences. Those technologies speed up data collection,compilation, and analysis; make new kinds of analysis practical;and shorten the time between discovery and application.Science Is Organized Into ContentDisciplines and Is Conducted in Various Institutions
Organizationally, science can be thought of as the collectionof all of the different scientific fields, or contentdisciplines. From anthropology through zoology, there are dozensof such disciplines. They differ from one another in many ways,including history, phenomena studied, techniques and languageused, and kinds of outcomes desired. With respect to purpose andphilosophy, however, all are equally scientific and together makeup the same scientific endeavor. The advantage of havingdisciplines is that they provide a conceptual structure fororganizing research and research findings. The disadvantage isthat their divisions do not necessarily match the way the worldworks, and they can make communication difficult. In any case,scientific disciplines do not have fixed borders. Physics shadesinto chemistry, astronomy, and geology, as does chemistry intobiology and psychology, and so on. New scientific disciplines(astrophysics and sociobiology, for instance) are continuallybeing formed at the boundaries of others. Some disciplines growand break into subdisciplines, which then become disciplines intheir own right.
Universities, industry, and government are also part of thestructure of the scientific endeavor. University research usuallyemphasizes knowledge for its own sake, although much of it isalso directed toward practical problems. Universities, of course,are also particularly committed to educating successivegenerations of scientists, mathematicians, and engineers.Industries and businesses usually emphasize research directed topractical ends, but many also sponsor research that has noimmediately obvious applications, partly on the premise that itwill be applied fruitfully in the long run. The federalgovernment funds much of the research in universities and inindustry but also supports and conducts research in its manynational laboratories and research centers. Private foundations,public-interest groups, and state governments also supportresearch.
Funding agencies influence the direction of science by virtueof the decisions they make on which research to support. Otherdeliberate controls on science result from federal (and sometimeslocal) government regulations on research practices that aredeemed to be dangerous and on the treatment of the human andanimal subjects used in experiments.There Are Generally Accepted EthicalPrinciples in the Conduct of Science
Most scientists conduct themselves according to the ethicalnorms of science. The strongly held traditions of accuraterecordkeeping, openness, and replication, buttressed by thecritical review of one"s work by peers, serve to keep the vastmajority of scientists well within the bounds of ethicalprofessional behavior. Sometimes, however, the pressure to getcredit for being the first to publish an idea or observationleads some scientists to withhold information or even to falsifytheir findings. Such a violation of the very nature of scienceimpedes science. When discovered, it is strongly condemned by thescientific community and the agencies that fund research.
Another domain of scientific ethics relates to possible harmthat could result from scientific experiments. One aspect is thetreatment of live experimental subjects. Modern scientific ethicsrequire that due regard must be given to the health, comfort, andwell-being of animal subjects. Moreover, research involving humansubjects may be conducted only with the informed consent of thesubjects, even if this constraint limits some kinds ofpotentially important research or influences the results.Informed consent entails full disclosure of the risks andintended benefits of the research and the right to refuse toparticipate. In addition, scientists must not knowingly subjectcoworkers, students, the neighborhood, or the community to healthor property risks without their knowledge and consent.
The ethics of science also relates to the possible harmfuleffects of applying the results of research. The long-termeffects of science may be unpredictable, but some idea of whatapplications are expected from scientific work can be ascertainedby knowing who is interested in funding it. If, for example, theDepartment of Defense offers contracts for working on a line oftheoretical mathematics, mathematicians may infer that it hasapplication to new military technology and therefore would likelybe subject to secrecy measures. Military or industrial secrecy isacceptable to some scientists but not to others. Whether ascientist chooses to work on research of great potential risk tohumanity, such as nuclear weapons or germ warfare, is consideredby many scientists to be a matter of personal ethics, not one ofprofessional ethics.Scientists Participate in PublicAffairs Both as Specialists and as Citizens
Scientists can bring information, insights, and analyticalskills to bear on matters of public concern. Often they can helpthe public and its representatives to understand the likelycauses of events (such as natural and technological disasters)and to estimate the possible effects of projected policies (suchas ecological effects of various farming methods). Often they cantestify to what is not possible. In playing this advisory role,scientists are expected to be especially careful in trying todistinguish fact from interpretation, and research findings fromspeculation and opinion; that is, they are expected to make fulluse of the principles of scientific inquiry.
Even so, scientists can seldom bring definitive answers tomatters of public debate. Some issues are too complex to fitwithin the current scope of science, or there may be littlereliable information available, or the values involved may lieoutside of science. Moreover, although there may be at any onetime a broad consensus on the bulk of scientific knowledge, theagreement does not extend to all scientific issues, let alone toall science-related social issues. And of course, on issuesoutside of their expertise, the opinions of scientists shouldenjoy no special credibility.
In their work, scientists go to great lengths to avoidbiastheir own as well as that of others. But in matters ofpublic interest, scientists, like other people, can be expectedto be biased where their own personal, corporate, institutional,or community interests are at stake. For example, because oftheir commitment to science, many scientists may understandablybe less than objective in their beliefs on how science is to befunded in comparison to other social needs.