Guest guest Posted December 8, 2000 Report Share Posted December 8, 2000 >Ray Wolfe <raywolfe >vedic108 >Philosophy of Scientific Reasoning >Fri, 08 Dec 2000 15:17:21 -0800 > >I thought this well-written essay might convey the nature of scientific >proof and how it differs from other proofs or interpretations of truth and >fact. Cheers! > > >The Scientific Method > > > 1.1: What is the "scientific method"? > >The scientific method is the best way yet discovered for winnowing the >truth from lies and delusion. The simple version looks >something like this: > > 1.Observe some aspect of the universe. > 2.Invent a theory that is consistent with what you have observed. > 3.Use the theory to make predictions. > 4.Test those predictions by experiments or further observations. > 5.Modify the theory in the light of your results. > 6.Go to step 3. > >This leaves out the co-operation between scientists in building theories, >and the fact that it is impossible for every scientist to >independently do every experiment to confirm every theory. Because life is >short, scientists have to trust other scientists. So a >scientist who claims to have done an experiment and obtained certain >results will usually be believed, and most people will not >bother to repeat the experiment. > >Experiments do get repeated as part of other experiments. Most scientific >papers contain suggestions for other scientists to >follow up. Usually the first step in doing this is to repeat the earlier >work. So if a theory is the starting point for a significant >amount of work then the initial experiments will get replicated a number of >times. > >Some people talk about "Kuhnian paradigm shifts". This refers to the >observed pattern of the slow extension of scientific >knowledge with occasional sudden revolutions. This does happen, but it >still follows the steps above. > >Many philosophers of science would argue that there is no such thing as the >scientific method. > > 1.2: What is the difference between a fact, a theory and a hypothesis? > >In popular usage, a theory is just a vague and fuzzy sort of fact. But to a >scientist a theory is a conceptual framework that >explains existing facts and predicts new ones. For instance, today I saw >the Sun rise. This is a fact. This fact is explained by >the theory that the Earth is round and spins on its axis while orbiting the >sun. This theory also explains other facts, such as the >seasons and the phases of the moon, and allows me to make predictions about >what will happen tomorrow. > >This means that in some ways the words fact and theory are interchangeable. >The organisation of the solar system, which I >used as a simple example of a theory, is normally considered to be a fact >that is explained by Newton's theory of gravity. And >so on. > >A hypothesis is a tentative theory that has not yet been tested. Typically, >a scientist devises a hypothesis and then sees if it >"holds water" by testing it against available data. If the hypothesis does >hold water, the scientist declares it to be a theory. > >An important characteristic of a scientific theory or hypotheis is that it >be "falsifiable". This means that there must be some >experiment or possible discovery that could prove the theory untrue. For >example, Einstein's theory of Relativity made >predictions about the results of experiments. These experiments could have >produced results that contradicted Einstein, so the >theory was (and still is) falsifiable. > >On the other hand the theory that "there is an invisible snorg reading this >over your shoulder" is not falsifiable. There is no >experiment or possible evidence that could prove that invisible snorgs do >not exist. So the Snorg Hypothesis is not scientific. >On the other hand, the "Negative Snorg Hypothesis" (that they do not exist) >is scientific. You can disprove it by catching one. >Similar arguments apply to yetis, UFOs and the Loch Ness Monster. See also >question 5.2 on the age of the Universe. > > 1.3: Can science ever really prove anything? > >Yes and no. It depends on what you mean by "prove". > >For instance, there is little doubt that an object thrown into the air will >come back down (ignoring spacecraft for the moment). >One could make a scientific observation that "Things fall down". I am about >to throw a stone into the air. I use my observation >of past events to predict that the stone will come back down. Wow - it did! > >But next time I throw a stone, it might not come down. It might hover, or >go shooting off upwards. So not even this simple fact >has been really proved. But you would have to be very perverse to claim >that the next thrown stone will not come back down. >So for ordinary everyday use, we can say that the theory is true. > >You can think of facts and theories (not just scientific ones, but ordinary >everyday ones) as being on a scale of certainty. Up at >the top end we have facts like "things fall down". Down at the bottom we >have "the Earth is flat". In the middle we have "I will >die of heart disease". Some scientific theories are nearer the top than >others, but none of them ever actually reach it. Skepticism >is usually directed at claims that contradict facts and theories that are >very near the top of the scale. If you want to discuss ideas >nearer the middle of the scale (that is, things about which there is real >debate in the scientific community) then you would be >better off asking on the appropriate specialist group. > > 1.4: If scientific theories keep changing, where is the Truth? > >In 1666 Isaac Newton proposed his theory of gravitation. This was one of >the greatest intellectual feats of all time. The theory >explained all the observed facts, and made predictions that were later >tested and found to be correct within the accuracy of the >instruments being used. As far as anyone could see, Newton's theory was the >Truth. > >During the nineteenth century, more accurate instruments were used to test >Newton's theory, and found some slight >discrepancies (for instance, the orbit of Mercury wasn't quite right). >Albert Einstein proposed his theories of Relativity, which >explained the newly observed facts and made more predictions. Those >predictions have now been tested and found to be >correct within the accuracy of the instruments being used. As far as anyone >can see, Einstein's theory is the Truth. > >So how can the Truth change? Well the answer is that it hasn't. The >Universe is still the same as it ever was, and Newton's >theory is as true as it ever was. If you take a course in physics today, >you will be taught Newton's Laws. They can be used to >make predictions, and those predictions are still correct. Only if you are >dealing with things that move close to the speed of light >do you need to use Einstein's theories. If you are working at ordinary >speeds outside of very strong gravitational fields and use >Einstein, you will get (almost) exactly the same answer as you would with >Newton. It just takes longer because using Einstein >involves rather more maths. > >One other note about truth: science does not make moral judgements. Anyone >who tries to draw moral lessons from the laws >of nature is on very dangerous ground. Evolution in particular seems to >suffer from this. At one time or another it seems to have >been used to justify Nazism, Communism, and every other -ism in between. >These justifications are all completely bogus. >Similarly, anyone who says "evolution theory is evil because it is used to >support Communism" (or any other -ism) has also >strayed from the path of Logic. > > 1.5: "Extraordinary evidence is needed for an extraordinary claim" > >An extraordinary claim is one that contradicts a fact that is close to the >top of the certainty scale discussed above. So if you are >trying to contradict such a fact, you had better have facts available that >are even higher up the certainty scale. > > 1.6: What is Occam's Razor? > >Ockham's Razor ("Occam" is a Latinised variant) is the principle proposed >by William of Ockham in the fifteenth century that >"Pluralitas non est ponenda sine neccesitate", which translates as >"entities should not be multiplied unnecessarily". Various other >rephrasings have been incorrectly attributed to him. In more modern terms, >if you have two theories which both explain the >observed facts then you should use the simplest until more evidence comes >along. See W.M. Thorburn, "The Myth of Occam's >Razor," Mind 27:345-353 (1918) for a detailed study of what Ockham actually >wrote and what others wrote after him. > >The reason behind the razor is that for any given set of facts there are an >infinite number of theories that could explain them. For >instance, if you have a graph with four points in a line then the simplest >theory that explains them is a linear relationship, but you >can draw an infinite number of different curves that all pass through the >four points. There is no evidence that the straight line is >the right one, but it is the simplest possible solution. So you might as >well use it until someone comes along with a point off the >straight line. > >Also, if you have a few thousand points on the line and someone suggests >that there is a point that is off the line, it's a pretty fair >bet that they are wrong. > >The following argument against Occam's Razor is sometime proposed: > > This simple hypothesis was shown to be false; the truth was more >complicated. So Occam's Razor doesn't work. > >This is a strawman argument. The Razor doesn't tell us anything about the >truth or otherwise of a hypothesis, but rather it tells us >which one to test first. The simpler the hypothesis, the easier it is to >shoot down. > >A related rule, which can be used to slice open conspiracy theories, is >Hanlon's Razor: "Never attribute to malice that which >can be adequately explained by stupidity". This definition comes from "The >Jargon File" (edited by Eric Raymond), but one >poster attributes it to Robert Heinlein, in a 1941 story called "Logic of >Empire". > > 1.7: Galileo was persecuted, just like researchers into <X> today. > >People putting forward extraordinary claims often refer to Galileo as an >example of a great genius being persecuted by the >establishment for heretical theories. They claim that the scientific >establishment is afraid of being proved wrong, and hence is >trying to suppress the truth. > >This is a classic conspiracy theory. The Conspirators are all those >scientists who have bothered to point out flaws in the claims >put forward by the researchers. > >The usual rejoinder to someone who says "They laughed at Columbus, they >laughed at Galileo" is to say "But they also laughed >at Bozo the Clown". (From Carl Sagan, Broca's Brain, Coronet 1980, p79). > >Incidentally, stories about the persecution of Galileo Galilei and the >ridicule Christopher Columbus had to endure should be >taken with a grain of salt. > >During the early days of Galileo's theory church officials were interested >and sometimes supportive, even though they had yet to >find a way to incorporate it into theology. His main adversaries were >established scientists - since he was unable to provide >HARD proofs they didn't accept his model. Galileo became more agitated, >declared them ignorant fools and publicly stated that >his model was the correct one, thus coming in conflict with the church. > >When Columbus proposed to take the "Western Route" the spherical nature of >the Earth was common knowledge, even though >the diameter was still debatable. Columbus simply believed that the Earth >was a lot smaller, while his adversaries claimed that >the Western Route would be too long. If America hadn't been in his way, he >most likely would have failed. The myth that "he >was laughed at for believing that the Earth was a globe" stems from an >American author who intentionally adulterated history. > > 1.8: What is the "Experimenter effect"? > >It is unconscious bias introduced into an experiment by the experimenter. >It can occur in one of two ways: > > Scientists doing experiments often have to look for small effects or >differences between the things being experimented > on. > > Experiments require many samples to be treated in exactly the same >way >in order to get consistent results. > >Note that neither of these sources of bias require deliberate fraud. > >A classic example of the first kind of bias was the "N-ray", discovered >early this century. Detecting them required the >investigator to look for very faint flashes of light on a scintillator. >Many scientists reported detecting these rays. They were >fooling themselves. For more details, see "The Mutations of Science" in >Science Since Babylon by Derek Price (Yale Univ. >Press). > >A classic example of the second kind of bias were the detailed >investigations into the relationship between race and brain >capacity in the last century. Skull capacity was measured by filling the >empty skull with lead shot or mustard seed, and then >measuring the volume of beans. A significant difference in the results >could be obtained by ensuring that the filling in some skulls >was better settled than others. For more details on this story, read >Stephen Jay Gould's The Mismeasure of Man. > >For more detail see: > >T.X. Barber, Pitfalls of Human Research, 1976. >Robert Rosenthal, Pygmalion in the Classroom. > >[These were recommended by a correspondent. Sorry I have no more >information.] > > 1.9: How much fraud is there in science? > >In its simplest form this question is unanswerable, since undetected fraud >is by definition unmeasurable. Of course there are >many known cases of fraud in science. Some use this to argue that all >scientific findings (especially those they dislike) are >worthless. > >This ignores the replication of results which is routinely undertaken by >scientists. Any important result will be replicated many >times by many different people. So an assertion that (for instance) >scientists are lying about carbon-14 dating requires that a >great many scientists are engaging in a conspiracy. See the previous >question. > >In fact the existence of known and documented fraud is a good illustration >of the self-correcting nature of science. It does not >matter if a proportion of scientists are fraudsters because any important >work they do will not be taken seriously without >independent verification. Hence they must confine themselves to pedestrian >work which no-one is much interested in, and >obtain only the expected results. For anyone with the talent and ambition >necessary to get a Ph.D this is not going to be an >enjoyable career. > >Also, most scientists are idealists. They perceive beauty in scientific >truth and see its discovery as their vocation. Without this >most would have gone into something more lucrative. > >These arguments suggest that undetected fraud in science is both rare and >unimportant. > >The above arguments are weaker in medical research, where companies >frequently suppress or distort data in order to support >their own products. Tobacco companies regularly produce reports "proving" >that smoking is harmless, and drug companies >have both faked and suppressed data related to the safety or effectiveness >or major products. > >For more detail on more scientific frauds than you ever knew existed, see >False Prophets by Alexander Koln. > >The standard textbook used in North America is Betrayers of the Truth: >Fraud and Deceit in Science by William Broad and >Nicholas Wade (Oxford 1982). > >There is a mailing list SCIFRAUD for the discussion of fraud and >questionable behaviour in science. To , send "sub >scifraud <Your Name>" to "listserv". > > 1.9.1: Did Mendel fudge his results? > >Gregor Mendel was a 19th Century monk who discovered the laws of >inheritance (dominant and recessive genes etc.). More >recent analysis of his results suggest that they are "too good to be true". >Mendelian inheritance involves the random selection of >possible traits from parents, with particular probabilities of particular >traits. It seems from Mendel's raw data that chance played >a smaller part in his experiments than it should. This does not imply fraud >on the part of Mendel. > >First, the experiments were not "blind" (see the questions about double >blind experiments and the experimenter effect). >Deciding whether a particular pea is wrinkled or not needs judgement, and >this could bias Mendel's results towards the >expected. This is an example of the "experimenter effect". > >Second, Mendel's Laws are only approximations. In fact it does turn out >that in some cases inheritance is less random than his >Laws state. > >Third, Mendel might have neglected to publish the results of `failed' >experiments. It is interesting to note that all 7 of the >characteristics measured in his published work are controlled by single >genes. He did not report any experiments with more >complicated characteristics. Mendel later started experiments with a more >complex plant, hawkweed, could not interpret the >results, got discouraged and abandoned plant science. > >See The Human Blueprint by Robert Shapiro (New York: St. Martin's, 1991) p. >17. > > 1.10: Are scientists wearing blinkers? > >One of the commonest allegations against mainstream science is that its >practitioners only see what they expect to see. >Scientists often refuse to test fringe ideas because "science" tells them >that this will be a waste of time and effort. Hence they >miss ideas which could be very valuable. > >This is the "blinkers" argument, by analogy with the leather shields placed >over horses eyes so that they only see the road >ahead. It is often put forward by proponents of new-age beliefs and >alternative health. > >It is certainly true that ideas from outside the mainstream of science can >have a hard time getting established. But on the other >hand the opportunity to create a scientific revolution is a very tempting >one: wealth, fame and Nobel prizes tend to follow from >such work. So there will always be one or two scientists who are willing to >look at anything new. > >If you have such an idea, remember that the burden of proof is on you. >Posting an explanation of your idea to sci.skeptic is a >good start. Many readers of this group are professional scientists. They >will be willing to provide constructive criticism and >pointers to relevant literature (along with the occasional rasberry). >Listen to them. Then go away, read the articles, improve >your theory in the light of your new knowledge, and then ask again. >Starting a scientific revolution is a long, hard slog. Don't >expect it to be easy. If it was, we would have them every week. > > > > The Left Hemisphere > The Web Wanderer > >Bill Latura <blatura > ______________________________\ _____ Get more from the Web. 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