Americans have two different experiences of science. A few of us produce science (more, but not many, are trained to produce it); Most of us consume science.
Science for consumption is a load of absolute statements: "Water freezes at 0 centigrade and boils at 100 centigrade." Hence, most of the non-science which people label as "science" so that you'll believe it is just a collection of absolute statements: "social science," "scientific socialism," and the like.[1][2]
The experience of people who produce science is quite different. One person takes one side and produces evidence; the other person takes the other side and produces evidence. Other scientists are persuaded -- or, quite often, not.
Scientific American occasionally prints a pair of articles, each by a recognised authority, taking opposite sides of an issue. Science articles for people who only consume science, on the other hand, only print "now scientists know [fitb]" articles. When, as often happens, the evidence supports the other side a few months later, the papers print "now scientists know [whatever contradicts the last report]."
This dichotomy has consequences in how science interacts with politics whenever it does. Details after the jump.
The array-of-absolute-statements method of teaching science is, as far as I can figure out, unavoidable. I can remenber a freshman chemistry class at MIT where the book gave a number for the water molecules involved in an H+ ion.[3] The professor said, "this is wrong; later research has it at this number; write it in." We all dutifully wrote it in. Nobody in the class was astonished that a book could list a quantity which was subject to later correction. We were, if not scientists, at least scientists-in-training.
Science books don't say "we think this, subject to later checks." They say "this is true." But, those who know more than a modicum of science know that the data are always subject to later checks. And they have some feeling for likely the statement is of being corrected. (If the chemistry professor had said "Water is really H3O," we'd have laughed.)
The first thing that opponents of particular scientific findings, relativity as well as evolution and global warming, point to is that dissent is possible in that particular area. And dissent is possible in any particular area. Anomalies proliferate. The second thing that they emphasize is that the explanation for the anomaly is that the scientific finding that they oppose is false.
Now, the idea of "critical experiment" is an old one. Ben Franklin became the pre-eminent scientist of his time by figuring out a long series of critical experiments having -- mostly -- to do with electricity. There was one hypothesie and a contradictory one. He conducted an experiment which would go one way if the first hypothesis were correct and the other way if the other were correct. Einstein was complimented on a group of astronomical observations which seemed to verify general relativity: "You have been proven correct." He replied "A million experiments can't prove me correct; one can prove me wrong."
Actually -- though -- in logic, an experiment doesn't prove one assertion wrong. An anomaly shows that the entire set of assumptions can't be all correct. One of them, at least, must be wrong. Each of us has a mental heirarchy as to which assumptions are likely to be wrong. The first thing that expermenters look for is whether the experiment was conducted correctly. (Diabetics are warned when they get a totally weird blood sugar reading: "Wash your hands carefully and test again." It's much more likely to be a dab of sugar on your finger than a 300 level actually in your blood.)
When the anomaly has been repeated, and other experimenters in different labs have all confirmed it, then something is wrong with the set of theories. Theoretical scientists look for the least-established link as the most likely to be wrong; they are taught to avoid looking for an entire restructuring, although every scientists dreams of coming upon one of those.
(More than a century ago, a doctoral candidate in Scandinavia looked at a variety of anomalies in the behavior of solutions. He explained them all with one hypothesis. His dissertation was accepted, although with the laowest passing grade. Dissertatinos aren't supposed to challenge so many theories, but the explanation did make sense of all of them. Well, he was right. Some years later, he received the Nobel Prize for the ionic theory of solutions.)
Scientists look for the minimal new assumption which will explain anomalies. Crackpots end to look for something more like a maximal new assumption.
If two electrons undergo the process which makes them "entangled," and then are moved a great distance apart, and then one electron is tested for north spin and tests positive, and the other electron is tested for north spin, it will always test negative -- even if the electrons are so far apart and the tests are so close together in time that light could not travel from one experiment to the other in the time between the experiments. The crackpot explanation is "every particle is in constant instantatneous communication with every other particle in the universe." Ignore that these crackpots assume that "at the same time" is a meaningful concept for far-distant events. They are explaing the agreement of a specific pair of electrons by the mystic communication of every particle with every other one.
Lay challengers of scientific findings, on the other hand, tend to regard their particular nemesis as the first point to abandon.
Is there an anomaly in the fossil record? (There are many.) Then the explanation of the creationists is that Darwin was wrong. Some years ago a very old layer of rock was uncovered with footprints which didn't show claws. Creationists were quick to seize that evidence -- although they generally ignore footprints, which contradict their commonest explanations for the regular strata of fossils[4]. "These are human footprints. See??? Humans lived back then. Closer examination showed that the footprints did have claws. The mud in which the prints had originally been made turned into hard rock; the next layer of rock turned into softer rock; the softer rock was eroded away, leaving the footprints out in the open -- except that the soft rock in the narrow spaces made by claws had been protected from erosion.
When a doubter of global warming showed Alexander Cockburn graphs of fossil fuel burning and of atmospheric CO2 covering the period of the Great Depression, Cockburn was convinced that Global Warming had been refuted. (The graph of atmospheric CO2 increased smoothly; the graph of fossil fuel burning plunged.) A scientist would have asked first where the figures for atmospheric CO2 came from. (The direct measurement of atmospheric CO2 in the present observatory began in 1958. Local CO2 amounts are, obviously, heavily influenced by locality; are you downwind from a smokestack or from a forest?)
Doubters of any particular scientific finding are likely to claim persecution if schoolchildren aren't taught that there are anomalies in this arena. Actually, there are anomalies in every arena. Carbon monoxide was beyond the levle of the elementary chemistry that I was taught. (I don't know whether practicing chemists had an explanation back then.) Carbon had four places for extra electrons; oxygen had two extra electrons, There was no way that these two atoms should combine in that way. Nobody cited that as a reason to go back to the phlogiston theory; they just accepted that there was an anomaly and went on.
Creationists want schoolchildren taught that there are controversies and anomalies in the fossil record. This would be a contrast to all the other science as schoolchildren are taught it. It's not a contrast to other scientific fields as scientists experience them.
Creationists -- at least young-earth creatinists -- really have a harder row to hoe than deniers of global warming. Our understanding of astrophysics, geology, nuclear decay, nearly every branch of science, is locked in to the long timeline consistent with evolution.
There are only a few scientific areas which the deniers of global warming must challenge. They usually avoid the links
- fossil-fuel burning
- atmospheric CO2
- global warming.
Instead, they deny that there is a link between global warming and fossil-tuel burning without saying whether this means that CO2 going up a chimney then disappears or whether an increase in atmospheric CO2 magically does not retain more heat energy on earth, even though the CO2 at the begining of the industrial era did (and does) make the earth much warmer than the average temperature of the moon.
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[1] "Science" in terms which are not involved with "natural science" usually means: "We are like physics." They give a bunch of absolute statements. Botany,as another example of science, contains too much observation for the people who want to have their assertions taken as science. "Christian Science," OTOH, has the science of medicine in mind.
[2] Social Science:
I'll admit that some "social science," Anthropology most especially, involves observations which are the equivalent of natural history. That's as good science as any other.
Economics, OTOH, seems to me to be a very poor imitation of freshman physics. That class is full of such aproximations as "frictionless plane," "rigid body," and "perfect gas." Any undergraduate who missapplies these terms, or assumes that they qre absolute, is lucky to suffer merely the sneers of his professor; he risks a failing grade. Economics is centered on the "auction market." This is a possibly-helpful aproximation. Economics professors, not only their undergraduate students, treat it as if reality was constrained to fit that aproximation. Read sometime an Economics text on why the companies who advertise in newspapers are all wasting their money; it's a scream.
[3] The hydrogen nucleus is a proton, much too small to enter into solution in water. Instead, the "H+" ion is a psuedo-molecule of the hydrogen nucleus and several water molecules. Each of these is oriented so that the oxygen atoms are toward the lone nucleus.
[4] Some Creatinoists "explain" the layers of rock which contain different fossil bones in terms of one flood which deposited the bones in layers according to "heaviest first." (The dinosaurs that schoolchildren know were very large and heavy. They don't know about the first ones which were about as large as a chicken. And denser, rather than heavier, material sink faster -- never mind.) But the footprints show that these layers of rock were once mud on which animals walked. Hardly typical of one sole flood.