Classroom notes for: Radiation and Life 98.101.201 Professor: Thomas M. Regan Pinanski 206 ext 3283
Critical Thinking Science is more than just a collection of facts- it s a way of thinking about the world around us. In particular science requires critical thinking. You apply critical thinking every day. For instance, consider the claims of TV commercials. Does one detergent makes clothes whiter than another (Tide vs. Whisk)? You will try both brands to verify the claim. When planning a trip to Cape Cod, you receive advice as to the shortest route (495 straight to the Cape vs. 3 S to 128 S back to 3 S to the Cape). You will try both routes to determine which is the quickest journey, or will consult on-line travel planners.
The Scientific Method The Scientific Method formalizes the process of critical thinking. The Greek philosopher Leucippus (5 th century B.C.) was the first to state categorically that every event has a natural cause. This rules out all (indiscriminate and/or continuous) intervention by the supernatural and represents the scientific view held today. (Asimov s Chronology of Science and Discovery, Asimov, p. 47) Francis Bacon (1561-1626) was a pioneer of the Scientific Method. Francis Bacon, 1st Baron Verulam and Viscount Saint Albans, English philosopher and statesman; was one of the pioneers of modern scientific thought.(http://www.encarta.msn.com) Bacon's Novum Organum (1620) successfully influenced the acceptance of accurate observation and experimentation in science. In it he maintained that all prejudices and preconceived attitudes, which he called idols, must be abandoned. (http://www.encarta.msn.com) Bacon argued strenuously that deduction might do for mathematics but it would not do for science. The laws of science had to be induced; that is, established as generalizations drawn out of a vast mass of specific observation. (Asimov s Chronology of Science and Discovery, Asimov, p. 153)
The Scientific Method cont. Is this the only way of viewing the world? Some claim that the Scientific Method is a Western Philosophy, and is simply one world-view among many. As a philosophy it is subject to the cultural bias of Westerners, making it no more or less valid than any other philosophies. One good defense of science is that is it works. You can explain a falling apple many ways, but only the theory of gravity predicts the path of the earthbound apple and allows us to put men on the moon using the same mathematical formula. The Scientific Method does have its limitations, particularly when considering: 1) issues of how vs. why and 2) issues of morality ( right vs. wrong ). Whereas philosophy in general is concerned with the why as well as the how of things, science occupies itself with the latter question only, but in a scrupulously rigorous manner. (http://www.encarta.msn.com) Although scientists can provide extremely precise answers to the how of these theories, they cannot provide the answers to the why, not because their powers of observation or experimental abilities are limited, but rather because the questions are outside the realm of experimentation. (Modern Physics, p. 14) Considering the origins of the universe leaves us thinking: why? The atomic bomb was a marvelous technical achievement, but was it morally right?
The Scientific Method 1. 2. 3. 4. 5. 6. Formulate a problem. Generate an educated guess (hypothesis). Test the hypothesis by experimentation. Accept or reject the hypothesis. If the hypothesis is rejected, formulate a new hypothesis. If the hypothesis is accepted, continue to test it.
1. Formulate a problem. Be careful to consider only questions that science can answer. For instance, it may not be valid within the framework of the Scientific Method to consider the question: what is a good deed? While questions such as how much is a life worth? can be answered in technical terms.
2. Generate an Educated Guess (hypothesis). This guess may be inspired by previously collected data or by simple observations of the world (such as the moon rising and setting every night). A hypothesis is typically based on inductive reasoning; that is, drawing broad conclusions based upon specific observations or particular data. One type of inductive reasoning is known as simple enumeration, that is, drawing general conclusions from particular data. (http://www.encarta.msn.com) Applying simple enumeration to specific observations of the moon rising and setting each night would lead you to conclude that the moon rises and sets every night.
A hypothesis must be falsifiable (that is, testable) If you ever have a child who claims that an invisible monster lives under his/her bed- one that can t be seen, heard, smelled, touched, tasted, or otherwise detected- then you ve experienced a hypothesis that is not falsifiable; there is no way you can disprove the child s claim, so the existence of the creature then becomes a matter of faith, rather than something that is understandable by science. This is a difficult step, as it requires an active imagination; Albert Einstein recognized the importance of imagination in science, saying: "Imagination is more important than knowledge." (http://rescomp.stanford.edu/~cheshire/einsteinquotes.html) Interestingly, the ancient Greek philosophers, as well as thinkers as recent as Rene Descartes (of "I think, therefore I am" fame) and Gottfried Wilhelm Leibniz, stopped at this point, believing that questions could be answered by thought alone. (http://www.encarta.msn.com) The ancient Greeks tested none of their hypotheses by experiment, so convinced were they that the power of reason alone could be used to discover the hidden and mysterious laws of nature and that once reason had been applied to understanding a problem, no experiments were necessary. If theory and experiment were to disagree, they would argue, then there must be something wrong with the experiment! (Modern Physics, p. 12)
3.Test the hypothesis by experimentation. This too, is a difficult step, as proper experiments are hard to design/complete. The experiment must have proper control and experimental groups. That is, there must be two groups, and all factors between the two must be identical except the one (and only one) to be tested. For example, if you were to design an experiment to analyze the health impact of cigarette smoking, the control group would be non-smokers, while the experimental group would be smokers. Cigarette smoking in this case would have to be the only difference between the two groups; all other factorsdiet, exercise, alcohol consumption, etc - would have to be identical (or at least accounted for statistically). If the nonsmokers had a dramatically poorer diet, for instance, and as a result were in poorer health, you might falsely conclude that smoking poses no risk, or even that it is beneficial.
The experiment must be reproducible. On March 23 rd, 1989, B. Stanley Pons (b. 1943) and Martin Fleischmann (b. 1927), chemists at the Univ. of Utah, announced that an experiment conducted at room temperature using platinum and palladium electrodes immersed in heavy water (deuterium oxide) had produced excess heat and other by-products that they ascribed to a fusion reaction. Attempts to replicate their experiment produced initially conflicting results, but several early announcements of experimental confirmation were later retracted. (http://www.encyclopedia.com and (ttp://broccoli.caltech.edu/~goodstein/fusion.html) Unfortunately, when other scientists tried to duplicate the experiment, they were unable to confirm the cold fusion findings. They also reported inconsistencies in the Pons- Fleischmann data. After continuing controversy, a U.S. Department of Energy panel found a lack of convincing evidence to associate the reported anomalous heat with a nuclear process. (Asimov s Chronology of Science and Discovery, Asimov, p. 747)
4. Accept or reject the hypothesis. Objectivity is the key to this step. Objectivity indicates the attempt to observe things as they are, without falsifying observations to accord with some preconceived world-view. (http://www.encarta.msn.com) In other words, don t keep the data that you want to see because it suits your purposes. As of Spring 2000, there was debate in the medical community as to whether medical researchers should be allowed to invest in biotech or pharmaceutical companies for whom they are doing research. This poses a potential problem, for it might be easier for a doctor to see only data that supports his/her findings of the efficacy of a new drug that if approved, would significantly increase the value of a company s stocks.
Beware of mistaking causation with correlation. I understand that a medical study was once conducted that demonstrated babies born to mothers who had ultrasound tests performed while the babies were being carried in the womb are smarter than babies whose mothers did not receive these tests. Is this because the sound waves somehow alter the development of the fetus brain to make the baby smarter (causation)? Or could it simply be that the mothers having ultrasounds conducted are from better socio-economic backgrounds? Then the babies would have proper nutrition, better education, more stable surroundings, and in general better odds of growing up healthy and intelligent (correlation).
5. If the hypothesis is rejected, formulate a new hypothesis. This is not a bad thing; once a hypothesis is rejected, other scientists now know not to pursue that particular line of inquiry. This is helpful for the scientific community, because attention and resources can now be better directed towards other areas that promise to yield results
6. If the hypothesis is accepted, continue to test it. The testing never ends, as someone could uncover facts disproving the hypothesis. Even Albert Einstein recognized this and realized that someday his theories could be overturned. Scientists have been testing the validity of Einstein s Special Theory of Relativity almost since it was published in 1905. Display quote by Albert Einstein (1879-1955): The scientific theorist is not to be envied. For Nature, or more precisely experiment, is an inexorable and not very friendly judge of his work. It never says Yes to a theory. In the most favorable cases it says Maybe, and in the great majority of cases simply No. Probably every theory will some day experience its no - most theories, soon after conception.
Hypothesis vs. Theory vs. Law These are three terms often used interchangeably; however, they have very different meanings. Hypothesis has been defined. Theory can be loosely defined as a hypothesis that has withstood repeated attempts to disprove it. Another definition would be: an organized body of facts or explanations.(modern Physics, p. 13) Law would be an ultimate or universal truth ; however, Einstein s quote suggests that there is no such thing as a law, because there is always the possibility that something will be uncovered to disprove it. Einstein s Special Theory of Relativity is a perfect example, because with it he demonstrated that Newton s Laws of Motion are in fact not entirely correct.
Operational vs. Ultimate Truth The aim of science is to model the world around us in terms of operational truths; that is, it aims to provide an explanation of what s going on that allows us to make accurate future predications based on mathematical formulae. Are these models ultimate truths? Are they explanations of what is really happening? Few scientists would be so arrogant to make such a claim. It must be remembered that the search for ultimate truths or eternal laws is not a goal of science. (Modern Physics, p. 13) Consider the (in)famous wave-particle duality of light. In certain situations light behaves like a particle, while in others it behaves like a wave, basically depending upon the experiment being performed. Which is it really? What is the ultimate truth of the issue? Does it really matter as long as we can accurately model it, allowing us to make accurate predications of its behavior and hence to design devices using light to make our world a better place? This becomes an almost philosophical question, and many great minds have pondered it.
Science Defined Finally then, science can be loosely defined as: an organized system for the rigorous study of the natural world. On one slip of paper, have each student write down his/her favorite musical artist (solo performer or group) and collect the data.