15.8: Paradigms and Possible Causes

Your car's engine is gummed up today. This has never happened before. Could it be because at breakfast this morning you drank grapefruit juice rather than your usual orange juice? No, it couldn't be. Current science says this sort of explanation is silly. OK, forget the grapefruit juice. Maybe the engine is gummed up because today is Friday the 13th. No, that is silly, too. A scientist wouldn't even bother to check these explanations. Let's explore this intriguing notion of what science considers "silly" versus what it takes seriously. What causes the pain relief after swallowing a pain pill? Could it be the favorite music of the inventor? No, that explanation violates medical science's basic beliefs about what can count as a legitimate cause of what. Nor could the pain relief be caused by the point in time when the pill is swallowed. Time alone causes nothing, says modern science. The pain relief could be caused by the chemical composition of the pill, however, or perhaps by a combination of that with the mental state of the person who swallowed the pill. The general restrictions that a science places on what can be a cause and what can't are part of what is called the paradigm of the science. Every science has its paradigm.

That is, at any particular time, each science has its own particular problems that it claims to have solved; and, more important, it has its own accepted ways of solving problems that then serve as a model for future scientists who will try to solve new problems. These ways of solving problems, including the methods, standards, and generalizations generally held in common by the community of those practicing the science, is, by definition, the paradigm of that science.

The paradigm in medical science is to investigate what is wrong with sick people, not what is right with well people. For a second example, biological science is not sure what causes tigers to like meat rather than potatoes, but biologists are fairly sure the cause involves the chemical makeup of the meat, not the history of zipper manufacturing or the price of rice in China. The paradigm for biological science limits what counts as a legitimate biological explanation. When we take a science course or read a science book, we are slowly being taught the paradigm of that science and, with it, the ability to distinguish silly explanations from plausible ones. Silly explanations do not meet the basic requirement for being a likely explanation, namely coherence with the paradigm. Sensitivity to this consistency requirement was the key to understanding the earlier story about Brother Bartholomew. Scientists today say that phenomena should not be explained by supposing that Bartholomew or anybody else could see into the future; this kind of "seeing" is inconsistent with the current paradigm. It is easy to test whether people can foresee the future if you can get them to make specific predictions rather than vague ones. Successfully testing a claim that someone can foresee the future would be a truly revolutionary result, upsetting the whole scientific world-view, which explains why many people are so intrigued by tabloid reports of people successfully foretelling the future.

Exercise \(\PageIndex{1}\)

Even if you’ve never had a college biology course, you ought to be able to identify which explanation below, about why spiders don't get stuck in their own webs, deviates the most from the paradigm.

a. The color of the web causes the spider to wrinkle its feet, which in turn causes new, wet, webbing to flow out of the spider, yet only dry webbing can stick to a spider.
b. Spiders are possessed by demons that use demonic power to keep themselves unstuck.
c. A chemical oozing out of the spider's feet won't mix with the web, much the way oil won't mix with water.
d. The hot breath of the spider sends shock waves through the web, temporarily altering its chemical structure and thereby giving the spider the power to walk freely on the web.

Answer

Choice (a) is very strange, but the answer is (b). Demons are not supposed to be used in explanations that fit within the current paradigm of biological science. All the other possible answers are probably incorrect explanations, but at least they don't radically depart from the current paradigm.

Suppose a scientist wants to determine whether adding solid carbon dioxide to ice water will cool the water below 32 degrees Fahrenheit (0 degrees Celsius). The scientist begins with two glasses containing equal amounts of water at the same temperature. The glasses touch each other. Solid carbon dioxide is added to the first glass, but not the second. The scientist expects the first glass to get colder but the second glass not to. This second glass of water is the control because it is just like the other glass except that the causal factor being tested—the solid carbon dioxide—is not present in it. After twenty minutes, the scientist takes the temperature of the water in both glasses. Both are found to have cooled, and both are at the same temperature. A careless scientist might draw the conclusion that the cooling is not caused by adding the carbon dioxide, because the water in the control glass also got cooler. A more observant scientist might draw another conclusion, that the experiment wasn’t any good because the touching is contaminating the control. The two glasses should be kept apart during the experiment to eliminate contamination. The paradigm of the science dictates that the glasses not touch because it implies that glasses in contact will reach a common temperature in much faster than glasses not in contact.

For a second example of the contamination of experimental controls, suppose a biologist injects some rats with a particular virus and injects control rats with a placebo—some obviously ineffective substance such as a small amount of salt water. The biologist observes the two groups of rats to determine whether the death rate of those receiving the virus is significantly higher than the death rate of those receiving the placebo. If the test is well run and the data show such a difference, there is a correlation between the virus injection and dying. Oh, by the way, the injected rats are kept in the same cages with the control rats. Oops. This contamination will invalidate the entire experiment, won't it?

Reputable scientists know how to eliminate contamination, and they actively try to do so. They know that temperature differences and disease transmission can be radically affected by physical closeness. This background knowledge that guides experimentation constitutes another part of the paradigm of the sciences of physics and biology. Without a paradigm helping to guide the experimenter, there would be no way of knowing whether the control group was contaminated. There would be no way to eliminate experimenter effects, that is, the unintentional influence of the experimenter on the outcome of the experiment. There would be no way of running a good test. That fact is one more reason that so much of a scientist's college education is spent learning the science's paradigm.