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W HAT IS S CIENCE ? How do we know what we think we know?

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Presentation on theme: "W HAT IS S CIENCE ? How do we know what we think we know?"— Presentation transcript:

1 W HAT IS S CIENCE ? How do we know what we think we know?

2 O N T YPES OF K NOWLEDGE How do we know what we think we know? There are a variety of ways in which we obtain what we sometimes call “knowledge”. Culture based knowledge. My parents taught me this, so it must be true. Everyone in my circle of friends believes it, so it must be true. The news (CBS, CNN, Fox, MSNBC) reported this, so it must be true. My political leader or political party said this, so it must be true. Education based knowledge My teacher taught me this, so it must be true. I read it in a book, so it must be true. Religion based knowledge. The bible tells me so, so it must be true. My pastor tells me so, so it must be true. Everyone in my church believes it, so it must be true.

3 Personal experiential knowledge and knowledge based on intuition. I personally experienced this, so it must be true. Someone I know experienced this, so it must be true. My intuition tells me it is true. Science-Based knowledge. Knowledge based on empirical data, experimentation with the data, and repeated verification and attempts to disprove. Science is an active process of observation and investigation.

4 C ULTURE, E DUCATION, AND R ELIGION - B ASED K NOWLEDGE : A C ASE S TUDY Imagine humans in the “state of nature” attempting to make sense of the things around them: the sun, the moon, the four seasons, birth, death, and the four elements: earth, air, fire, water. Early cultures. Ancient Egyptians tried to understand their place in the universe and their belief system centered itself on nature, the earth, sky, moon, sun, stars, and the Nile River. Aten, the solar-disk, or Horus on the Horizon. Ra was the one and only creator in the universe. The sun god Atum traveled along Nut during the day and then was swallowed by Nut at night. Dawn was seen as Nut giving birth to Atum as the sky opened up to the light. Philolaus (c. 480–385 BCE), a Greek philosopher of the Pythagorean school, described an astronomical system in which the Earth, Moon, Sun, planets, and stars all revolved about a central fire. Aristarchus of Samos (310–230 BCE) also wrote of the heliocentric hypotheses in a book that does not survive. The great Greek historian Plutarch wrote that Aristarchus was accused of impiety for "putting the Earth in motion". In other words, he was ostracized for his views by religious authorities.

5 Most pre-modern cultures had conceptions of a flat Earth, including ancient Greece until the classical period, the Bronze Age and Iron Age civilizations of the Ancient Near East until the Hellenistic period, Ancient India until the Gupta period (early centuries AD) and China until the 17th century. It was typically held in the cultures of the New World until the time of European contact, and a flat Earth domed by the firmament in the shape of an inverted bowl is common in pre-scientific societies. The prevailing theory in Europe was the one that the Egyptian Ptolemy published in his Almagest circa 150 CE. Ptolemy's system drew on previous Greek theories in which the Earth was the stationary center of the universe. Stars were embedded in a large outer sphere which rotated rapidly, approximately daily, while each of the planets, the Sun, and the Moon were embedded in their own, smaller spheres. In 1543, the scientist Copernicus' dared to contradict this view. His vision of the universe was published in De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), in the year of his death, 1543, though he had formulated the theory several decades earlier. Copernicus’ theory posited that the earth was a sphere rotating on an axis and that the sun was the center of the universe. The Church banned Copernicus’ writings and theory, viewing it as heretical to an earth- centered universe created by God.

6 Galileo, sometimes called the “Father of Modern Science” championed Copernicanism, at a time when a large majority of philosophers and astronomers still subscribed to the geocentric view that the Earth is at the centre of the universe. After 1610, when he began publicly supporting the heliocentric view, which placed the Sun at the centre of the universe, he met with bitter opposition from contemporary philosophers and clerics, and two of the latter eventually denounced him to the Roman Inquisition early in In February 1616, although he had been cleared of any offence, the Catholic Church nevertheless condemned heliocentrism as "false and contrary to Scripture“, and Galileo was warned to abandon his support for it—which he promised to do. When he later defended his views in his most famous work, Dialogue Concerning the Two Chief World Systems, published in 1632, he was tried by the Inquisition, found "vehemently suspect of heresy", forced to recant, and spent the rest of his life under house arrest.

7 Example: For more than 2000 years up to the 19 th century, bloodletting (or blood-letting) was practiced. This was the withdrawal of often considerable quantities of blood from a patient to cure or prevent illness and disease. Bloodletting was based on an ancient system of medicine in which blood and other bodily fluid were considered to be "humors" whose proper balance maintained health. It was the most common medical practice performed by doctors from antiquity up to the late 19th century. Our Founding Father, George Washington, was subjected to bloodletting just prior to his death. Example: There was in much of history a belief that the weight of an object determines the rate at which it falls from the sky. Galileo Galilei overturned nearly 2,000 years of this Aristotelian belief that heavier bodies fall faster than lighter ones by proving that all bodies fall at the same rate. He did so through experiments conducted at the Leaning Tower of Pisa. You can see the apparatus he used to conduct these experiments in the Science Museum in Florence Italy. E XPERIENTIAL AND INTUITIVE K NOWLEDGE : C OMMON B ELIEFS CAN BE F ALSE

8 Political Science Example: Our culture tells us that democracy is the best form of government. However, based on experience associated with the Greek city-states, all the major Greek philosophers thought democracy was the worst form of government. This was the common view even up to the time of the American and French revolutions. Plato, in his critique of democracy in The Republic, claimed that it allows people to follow all their passions and drives without order or control; Aristotle claimed that the competing interests in a democracy makes for chaos rather than purposive and deliberated action. Democracy did not seem to work very democratically at all, in fact. In Athens, the democratic Assembly was usually dominated by a single powerful, charismatic individual; this individual often dominated the Assembly because of his presence or oratorical skill rather than his individual worth. Who was right? Is this a question which can be settled by debate and ideology, or might it be something worthy of scientific investigation? Would it be an important question to investigate? Suppose one found that democracy is not such a desirable form of government? What difficulties would one face in having one’s views accepted? Could we raise a similar set of questions about capitalism?

9 W HAT IS S CIENCE ? The word science derives from the Latin. The Latin verb “scire” means “to know” The Latin noun “scientia” means “knowledge” A Process: Science is an enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the world. A Body of Knowledge: An older meaning still in use today is that of Aristotle, for whom scientific knowledge was a body of reliable knowledge that can be logically and rationally explained. Studying the Natural World: The narrower sense of "science" that is also commonly used today developed as a part of science being a distinct enterprise of defining "laws of nature", based on early examples such as Kepler's laws, Galileo's laws, and Newton's laws of motion. Over the course of the 19th century, the word "science" became increasingly associated with the disciplined study of the natural world including physics, chemistry, geology and biology. Thus, when we think of science, we normally think of the “natural sciences”.

10 However, human behavior is also natural. Thus, this terminology left the study of human thought and society in a linguistic limbo, which was resolved by classifying these areas of academic study as social science. Political science is a social science. It is all about the study of political phenomena and behaviors.

11 T YPES OF S CIENCE Natural versus Social Sciences Scientific fields are commonly divided into two major groups: natural sciences, which study natural phenomena (including biological life), and social sciences, which study human behavior and societies. These groupings are both empirical sciences, which means the knowledge must be based on observable phenomena and capable of being tested for its validity by other researchers working under the same conditions. Basic versus Applied Science Basic science is the search for new knowledge. It is curiosity driven, and does not have to have any purpose other than building the body of scientific knowledge. Applied science is the search for solutions to practical problems using this knowledge. Although some scientific research is applied research into specific problems, a great deal of our understanding comes from the curiosity- driven undertaking of basic research. This leads to the possibility of technological advance that were not planned or sometimes even imaginable when the basic research was conducted.

12 E XAMPLES OF B ASIC S CIENCE THAT P RODUCED MORE B ASIC OR A PPLIED S CIENCE Watson and Crick conducted “basic research” on human DNA. They developed the double helix DNA model in the early 1950s. Since then, it has spurred biological research on what determines the fundamental characteristics of living beings. The double helix model has shaped genetic research and led directly to mapping living genomes. Medical breakthroughs have occurred, including the potential ability to splice genes for medical treatment, and the ability to detect genetic anomalies associated with human abnormalities, diseases, and their prevention. Another major contribution is genetic fingerprinting which has become important to modern forensic science. Recently researchers created the first artificial life form, which holds promise in such diverse areas as environmental cleanup and new methods of energy production. Without Watson and Crick’s double helix DNA model, the disciplines of biology and medicine would not offer the future promises that now seem apparent.

13 Einstein’s theory of general relativity, developed between 1907 and 1915, has served as a basis for the study of gravity and many other areas of astrophysics for a century. It explains why objects within objects in freefall experience weightlessness. It explains experimentally observed phenomena such as the bending of light and slowing of time. It provides the basis for understanding anomalies in the orbits of Mercury and other planets. It is currently the basis for understanding black holes where gravity is so intense that no light can escape. It is also the fundamental theory underlying the “big bang” theory of the origins of the universe. Without Einstein’s theory of general relativity the discipline of physics would be much different than it is today.

14 Other by-products of basic research. Electricity and its many uses at least partially resulted from basic research done by Benjamin Franklin, who was also one of the authors of our Constitution. Satellites were the culmination of our understanding of gravity and physics.. The internet was a culmination of telecommunications science. Transistors and microcircuits were applications of basic research on materials and molecules. Teflon and plastics were culminations of basic chemistry research. The discovery of infrared light was a product of basic research. Coming from this discovery were lasers and night vision optics. The discovery of radiation by Madam and Pierre Curie cost them their lives. However, it is widely used today for good. The point is that basic research may appear to the layperson as silly and of little value at the time. However, it may actually have great importance. This point was made by Michael Faraday when, allegedly in response to the question "what is the use of basic research?" he responded "Sir, what is the use of a new- born child?”

15 S OCIAL S CIENCE E XAMPLES Have the social sciences produced such positive benefits as these? Psychology- Understanding the causes of mental disease, both chemical and environmental. Understanding the processes of human learning. Psychology incorporates elements of chemistry, biology, and studying human nature. The biology side relates to how chemicals trigger responses in humans. For example, low levels of the chemical seratonin in the brain are a major cause of depression in humans. This is easily treated using drugs such as Prosac, Paxil, Zoloft, etc. Psychosis is often treated with Haldol, Thorazine, etc. Hyperactivity in children is treated with Ritalin, Wellbutrin, etc. Psychologists also use therapy to treat emotional problems.

16 Economics Economists study the allocation of scarce resources in economic systems. They develop theories to explain and improve efficiency. Positive benefits- More effectively controlling the macro-economy. Understanding micro-economic behavior has enabled changes that made the economy more efficient. Regulation and economies of scale. Regulation and externalities.

17 Political Science Political Scientists also study the allocation of scarce resources. One definition of politics, “Who gets what, when, where?” One method of allocation is democracy. Studies of the virtues and evils of democracy by political scientists John Adams, Thomas Jefferson, and James Madison formed a basis for the U.S. Constitution, Bill of Rights, etc. Political scientists also study institutions, both democratic and otherwise. Woodrow Wilson was largely responsible for transforming the modern presidency into a more powerful and policy oriented office. Political scientists who formed the 1937 Brownlow Commission were largely responsible for the design of the modern presidency, as well as the evolution of the modern Federal bureaucracy. Modern political scientists have played a large role in writing the Constitutions and designing the governments of various countries around the world, including the new Eastern European democracies, as well as countries in Latin America, Asia, and Africa emerging from authoritarian regimes.

18 W HAT S CIENTISTS D O Based on observations of a phenomenon, scientists generate a model or theory to explain a phenomenon of interest. This is an attempt to describe or depict the phenomenon in terms of a logical, physical, or mathematical representation. Empirical evidence is gathered, and hypotheses relating to the theory are evaluated. Hypotheses may be formulated using principles such as parsimony (traditionally known as "Occam's Razor") and are generally expected to fit well with other accepted facts related to the phenomena. When a hypothesis proves unsatisfactory, it is either modified or discarded. Once a hypothesis has survived testing, it may become adopted into the framework of a scientific theory. This is a logically reasoned, self-consistent model or framework for describing the behavior of certain natural phenomena. A theory typically describes the behavior of much broader sets of phenomena than a hypothesis; commonly, a large number of hypotheses can be logically bound together by a single theory. Thus a theory is a hypothesis explaining various other hypotheses. In that vein, theories are formulated according to most of the same scientific principles as hypotheses.

19 Experimentation is especially important in science to help establish a causational relationships. While performing experiments, scientists may have a preference for one outcome over another, and so it is important to ensure that science as a whole can eliminate this bias. At the core of science is norms. Scientists are expected to put aside any personal biases they may have. However, they may not always succeed in doing so. Further, some scholars don’t even try. However, normative bias can be minimized and even eliminated by process. Science requires transparency. It also requires careful experimental design and a thorough peer review process of the experimental results as well as any conclusions. After the results of an experiment are announced or published, it is normal practice for independent researchers to double-check how the research was performed, and to follow up by performing similar experiments to determine how dependable the results might be.

20 T HE S CIENTIFIC M ETHOD The scientific method refers to a body of techniques for investigating phenomena of interest, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering observable, empirical and measurable evidence subject to specific principles of reasoning. The Oxford English Dictionary says that scientific method is: "a method of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.“ Scientific researchers propose hypotheses as explanations of phenomena, and design experimental studies to test these hypotheses. These steps must be repeatable, to predict future results. Theories that encompass wider domains of inquiry may bind many independently derived hypotheses together in a coherent, supportive structure called a theory or model. Theories, in turn, may help form new hypotheses or place groups of hypotheses into context.

21 The four essential elements of a scientific method the following: Definition of Research Concepts (observations, definitions, and measurements of the subject of inquiry) Statement of Theory and Hypotheses (theoretical, hypothetical explanations of observations and measurements of the subject) A Priori Predictions (reasoning including logical deduction from the hypothesis or theory) Experiments (tests of all of the above) Each element of a scientific method is subject to peer review for possible mistakes or misleading results.

22 S CIENCE, C ERTAINTY, AND U NCERTAINTY Unlike a mathematical proof, a scientific theory is empirical, and is always open to falsification if new evidence is presented. That is, no theory is ever considered strictly certain as science works under a fallibilistic view (i.e. the belief that all claims of knowledge could, in principle, be mistaken). Instead, science is proud to make predictions with great probability, bearing in mind that the most likely event is not always what actually happens. There is a stochastic nature to all scientific knowledge. We can NEVER explain a phenomenon with 100% certainty. However, we may be able to assign a high probability of occurrence to a phenomenon. Science generally chooses to err on the conservative side. That is, for an experimental finding to be worthy of reporting, the probability of falsely rejecting a true null hypothesis must be low. In other words, researchers must meet a high standard of probability for a finding to be worthy. If we are going to err, then we prefer to err on the side of not misleading science, rather than on the side of new creative findings which may, in fact, be path-breaking.

23 S IMILARITIES AND D ISSIMILARITIES TO O THER F IELDS Note that this is quite similar to what occurs in the field of law. Under a “reasonable doubt” standard we must fail to convict when there is “reasonable doubt.” This is usually the standard in criminal cases. Why? Better that one guilty person goes free than that one innocent person goes to prison. However, it differs from the field of law where a standard of “preponderance of the evidence” is often used. This is usually the standard in civil cases. Using a conservative approach to reporting new scientific knowledge is also dissimilar to what occurs typically in the fields of public administration and business administration where analyses and recommendations are often based on relative perceived costs and benefits. Because science is always uncertain and we need some means of assessing certainty and uncertainty (i.e., probability or likelihood), statistics is VERY IMPORTANT to science.

24 M ODELS OF U NCERTAINTY Social scientists use at least three different models of uncertainty to evaluate their hypotheses: the probability model, the likelihood model, and the Bayesian model. The Probability Model- Here the assumption is that every statistical test one performs on an experiment is a new test. No attempt is made to take into account prior information. Each test is Tabula Rasa. Probability has well defined rules. One assigns a number between 0 and 1 to an event occurring. A probability of zero means that it will never occur. A probability of one means that it will always occur. Everything in between reflects our degree of uncertainty that an event will occur. The Likelihood Model- The Likelihood Model is similar to the probability model, except that the numbers we assign to an event occurring are not bounded between zero and one. Higher likelihood implies a greater chance of occurring. Lower likelihood implies a smaller chance of occurring. This model of uncertainty is a relative model which enables comparing substantive models.

25 The Bayesian Model – Thomas Bayes (pronounced: ‘be ɪ z) (c – 17 April 1761) was an English mathematician and Presbyterian minister. Calculate a posterior probability based on a prior probability and the likelihood. Note that this model of uncertainty allows one to incorporate prior information. Example: Suppose there is a school with 60% boys and 40% girls as its students. The female students wear trousers or skirts in equal numbers; the boys all wear trousers. An observer sees a (random) student from a distance, and what the observer can see is that this student is wearing trousers. What is the probability this student is a girl? The correct answer can be computed using Bayes' theorem. We need the components of the preceding function to calculate the probability. P(Trousers|Girl). Since girls are as likely to wear skirts as trousers, this is 0.5. P(Girl)=0.4. P(Trousers), or the probability of a (randomly selected) student wearing trousers regardless of any other information. Since half of the girls and all of the boys are wearing trousers, this is 0.5× ×0.6 = 0.8.

26 S CIENTIFIC R EVOLUTIONS ARE R ARE Theories and experimentation very rarely result in vast changes in our understanding. According to psychologist Keith Stanovich, it may be the media's overuse of words like "breakthrough" that leads the public to imagine that science is constantly proving everything it thought was true to be false. While there are such famous cases as the theory of relativity or Watson and Crick’s double helix that required a complete reconceptualization, these are extreme exceptions. Knowledge in science is gained by a gradual synthesis of information from different experiments, by various researchers, across different domains of science; it is more like a climb than a leap. Theories vary in the extent to which they have been tested and verified, as well as their acceptance in the scientific community. For example, heliocentric theory, the theory of evolution, and germ theory still bear the name "theory" even though, in practice, they are considered factual. Being skeptical and entertaining the possibility that one is incorrect is compatible with being correct. The scientist adhering to proper scientific method will doubt themselves even once they possess the truth.

27 Science avoids searching for a "magic bullet"; it avoids the single cause fallacy. This means a scientist would not ask merely "What is the cause of...", but rather "What are the most significant causes of...". This is especially the case in the more macroscopic fields of science (e.g. psychology, economics, political science). The rule of “parsimony” versus the “kitchen sink”. One way of developing a perfect explanation for a phenomenon under study would be to throw everything into our models. However, good science searches for parsimonious explanations. Example: Predicting presidential election outcomes. We could perfectly predict presidential election outcomes simply by constructing a model consisting of indicator variables for each year in which a presidential election has occurred. However, it would not “explain” very much theoretically. The more parsimonious approach is to look for a few explanatory variables. Political scientists can almost perfectly predict presidential election outcomes using the following model:

28 S CIENCE, THE M EDIA, AND P OLITICS Many factors damage the relationship of science to the media and the use of science and scientific arguments by politicians. As a broad generalization, many politicians and citizens seek certainties and facts while scientists typically offer only probabilities and caveats. Politicians' ability to be heard in the mass media frequently distorts scientific understanding by the public. Many people, including politicians and the media resist new scientific knowledge. Resistance to certain scientific ideas derives in large part from assumptions and biases that have been demonstrated experimentally by psychologists in young children and that may persist into adulthood. In particular, both adults and children resist acquiring scientific information that clashes with culture, education, personal experience, and intuition based domains.

29 Additionally, when learning information from other people, both adults and children are sensitive to the perceived trustworthiness of the source of that information. Who is perceived as trustworthy by the average citizen? Their parents? Their pastor? The “talking head” on Fox, MSNBC, CNN? Resistance to science, then, is particularly exaggerated in societies where nonscientific ideologies have the advantages of being both grounded in common sense and transmitted by trustworthy sources (i.e., religious authorities, parents, teachers, political leaders, the mass media). This resistance to science has important social implications. Because scientifically ignorant publics are unprepared to evaluate policies about such things as global warming, vaccination, genetically modified organisms, stem cell research, cloning, etc., policy may lag behind scientific understanding and reality.

30 S CIENCE B ASED K NOWLEDGE IS S UPERIOR Science is based on repeated empirical verification through experimentation. Science is probabilistic, never certain. We assign degrees of probability to our knowledge, not certainty. Laws are rare in science. Alternative theories are always considered. As expressed by Plato, “the only thing I know is that I know nothing.” Skepticism is the hall mark of a good scientist. We continually question, test, and retest. We call into question knowledge obtained through culture, intuition, common knowledge, and even other science. Scientific knowledge is devoid of culture, values, ideology, history, or intuition. This is not to say that scientists don’t have pre-conceptions based on culture, values, ideology, history, or intuition. They may also have conflicts of interest.

31 However, the nature of the process means that such factors do not usually enter into the scientific “body of knowledge.” Peer review Repeated experiments and replication Scientific standards and values Time Example: It was reported in 1998 in the journal Lancet (a respected British medical journal) that MMR vaccinations (Measles, Mumps, and Rubella) are a cause of autism in children. The study was peer reviewed and seemingly based on sound scientific evidence. However, the author had conflicts of interest and it was recently discovered through reevaluation that the data upon which much of the study was based was actually fabricated. It is now the accepted knowledge that the MMR vaccine has positive benefits that far outweigh potential costs.

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