Tuesday, May 20. 2008
It’s interesting that research suggesting a link between using a mobile phone while pregnant and subsequent behavioral problems in children was announced shortly after I posted an essay quoting Claude Bernard, a critic of statistical studies. But I’m not quite ready to declare a causal link between my post and the announcement.
According to an article in the UK Independent, the study is based on a survey of the mothers of 13,159 children born in Denmark in the late 1990s. It found that the children of mothers who used mobile phones at least two or three times per day while pregnant were much more likely to experience behavioral problems later. The article suggests the study (which will be published in the July issue of Epidemiology) is particularly credible because one of its authors was previously skeptical about the health risks associated with mobile phones. It also states that when the authors looked for other explanations such as smoking during pregnancy, family psychiatric history or socio-economic status they found that “…the association with mobile phone use got even stronger.”
Three potential problems with this study leap off the page. “Behavioral problems” is an extremely vague category. Are the authors certain that the problems were correctly diagnosed and have physiological causes?
The fact that one of the authors (UCLA Professor Leeka Kheifets) was previously skeptical about mobile phone use causing health problems is irrelevant. Presumably, she thought the research was worth doing.
It makes sense that the authors looked for other explanations. I have no problem with the fact that they found no correlation with smoking, family history, or socio-economic status. But I don’t see how that made the association with mobile phone use even stronger.
My overall reaction is that this research cast a very wide net and (surprise!) found something. But we are not even sure what it found. And we are a very long way from concluding that radio frequency radiation was the cause.
Monday, May 12. 2008
The latest flare up in the evolution versus intelligent design dispute has brought out some questionable assertions regarding the role of theory in science. One such claim is that a theory is a hypothesis that has passed a round of tests. That is, there are different degrees of certainty in science; ‘theory’ is simply the intermediate state between ‘hypothesis’ and ‘law’.
That is certainly good news for the proponents of reigning theories. But is it good for science? The history of science shows that relatively few theories endure—and even fewer endure without modification. More important, theory-as-partially-verified-hypothesis confuses the distinction between the facts that a theory attempts to explain and the explanation.
The French scientist Claude Bernard, widely considered the Father of Physiology, recommended that researchers treat all theories with skepticism. He had good reasons for this attitude. Bernard was at the forefront of the movement to liberate medicine from scholasticism and refashion it as a dynamic, experimental science. His classic work An Introduction to the Study of Experimental Medicine is worth quoting at length (all of the following quotes are found in Part 1, Section III):
The first condition to be fulfilled by men of science, applying themselves to the investigation of natural phenomena, is to maintain absolute freedom of mind, based on philosophic doubt. Yet we must not be in the least skeptical; we must believe in science, i.e., in determinism; we must believe in a complete and necessary relation between things, among the phenomena proper to living beings as well as in all others; but at the same time we must be thoroughly convinced that we know this relation only in a more or less approximate way, and that the theories we hold are far from embodying changeless truths. When we propound a general theory in our sciences, we are sure only that, literally speaking, all such theories are false. They are only partial and provisional truths which are necessary to us, as steps on which we rest, so as to go on with the investigation; they embody only the present state of our knowledge, and consequently they must change with the growth of science, and all the more often when sciences are less advanced in their evolution. On the other hand, our ideas come to us, as we said, in view of facts which have been previously observed and which we interpret afterword. Now countless sources of error may slip into our observations, and in spite of all our attention and sagacity, we are never sure of having seen everything, because our means of observation are often too imperfect. The result of all this is, then, that if reasoning guides us in experimental science, it does not necessarily force its deductions upon us. Our mind can always remain free to accept or to dispute these deductions. If an idea presents itself to us, we must not reject it simply because it does not agree with the logical deductions of a reigning theory. We may follow our feelings and our idea and give free rein to our imagination, as long as all our ideas are mere pretexts for devising new experiments that may supply us with convincing or unexpected and fertile facts.
Bernard is not saying that scientists should be extreme skeptics. Nor is he saying that theories are mere guesses. What he is saying is that theories are attempts to connect the factual dots within a logically consistent model. Theories can help lead us to new discoveries. But we must not let them blind us to facts that don’t fit the model.
Bernard proceeds to describe how unwarranted attachment to theories can lead to error:
If a doctor imagined that his reasoning had the value of a mathematician's, he would be utterly in error and would be led into the most unsound conclusions. This is unluckily what has happened and still happens to the men whom I shall call systematizers. These men start, in fact, from an idea which is based more or less on observation, and which they regard as an absolute truth. Then they reason logically and without experimenting, and from deduction to deduction they succeed in building a system which is logical, but which has no sort of scientific reality. Superficial persons often let themselves be dazzled by this appearance of logic; and discussions worthy of ancient scholasticism are thus sometimes renewed in our day. The excessive faith in reasoning, which leads physiologists to a false simplification of things, comes, on the one hand, from ignorance of the science of which they speak, and, on the other hand, from lack of a feeling for the complexity of natural phenomena. That is why we sometimes see pure mathematicians, with very great minds too, fall into mistakes of this kind; they simplify too much and reason about phenomena as they construct them in their minds, but not as they exist in nature.
He goes so far as to suggest that science can give rise to a unique form of superstition:
...We must trust our observations or our theories only after experimental verification. If we trust too much, the mind becomes bound and cramped by the results of its own reasoning; it no longer has freedom of action, and so lacks the power to break away from that blind faith in theories which is only scientific superstition.
Or as the great American inventor Edwin H. Armstrong was fond of saying, “It ain’t ignorance that causes all the trouble in this world. It’s the things people know that ain’t so”:
It has often been said that, to make discoveries, one must be ignorant. This opinion, mistaken in itself, nevertheless conceals a truth. It means that it is better to know nothing than to keep in mind fixed ideas based on theories whose confirmation we constantly seek, neglecting meanwhile everything that fails to agree with them. Nothing could be worse than this state of mind; it is the very opposite of inventiveness...
Educators would do well to heed Bernard’s words:
In scientific education, it is very important to differentiate, as we shall do later, between determinism which is the absolute principle of science, and theories which are only relative principles to which we should assign but temporary value in the search for truth. In a word, we must not teach theories as dogmas or articles of faith. By exaggerated belief in theories, we should give a false idea of science; we should overload and enslave the mind, by taking away its freedom, smothering its originality and infecting it with the taste for systems.
Finally, he points out that not only religious beliefs, but scientific beliefs, can obstruct the search for truth:
To sum up, two things must be considered in experimental science: method and idea. The object of method is to direct the idea which arises in the interpretation of natural phenomena and in the search for truth. The idea must always remain independent, and we must no more chain it with scientific beliefs than with philosophic or religious beliefs; we must be bold and free in setting forth our ideas, must follow our feeling, and must on no account linger too long in childish fear of contradicting theories...
Today, Bernard is revered as a champion of vivisection but shunned as an opponent of human clinical studies. Though he was wrong to assume animal research is sufficient, his skepticism towards the use of statistics in human studies was not entirely unwarranted. Scientists would do well to read his book today.
UPDATE May 13, 2008 - 10:00am Eastern:
According to Wikipedia, even the National Academy of Sciences has decided it's time to redefine theory. The Academy reasons that if a theory purports to explain a sufficiently large number of facts, then somehow that validates the explanation.
Never mind that there can be any number of theories to explain the same facts. Never mind that the Academy is essentially tossing out the bulk of philosophy of science.
NOTE: This post was originally titled Claude Bernard’s Take on “What is a Theory?”
Saturday, May 3. 2008
Few movies evoke intense emotional responses as does Ben Stein’s new release, Expelled: No Intelligence Allowed. People seem to line up on two sides: those who fear “big science” is trying to destroy religion and those who believe that intelligent design (ID) is biblical creationism in disguise.
The real issues run much deeper. This is a debate about who gets to decide what constitutes science and how, if at all, that decision should be enforced.
According to Expelled, “big science” has decided that Darwinian evolution is no longer a theory but a proven fact. Consequently, there is no place in science for ID. The movie does not demand equal time for ID; it simply argues that scientists should be free to pursue research based on ID as long as they are willing to submit their work to the same kind of scrutiny applied to other scientific research.
Critics accuse the movie’s producers of using dishonest tactics: The scholars who allege they were persecuted for their ID views are merely using that as an excuse. The movie unfairly links Darwinism to Nazism. And the movie’s producers deceived leading evolutionists in order to secure their participation, and then manipulated their words.
Unfortunately, this has become a debate about Ben Stein and Expelled. Let’s get back to the issues.
Evolution is the best theory we have to explain the similarities between diverse living organisms. These similarities provide compelling evidence that higher organisms are the result of an evolutionary process. However, evolution does not satisfactorily explain this process. It doesn’t give us a detailed account of how new species come into being. Nor does it tell us precisely how life began.
Intelligent design is not a competing theory. It does not attempt to explain the diversity of living organisms. It is a simple hypothesis that challenges Darwinian views regarding the origin of life and the sufficiency of natural selection to explain the development of higher organisms. I understand why many people feel that evolution is science and ID is not. They are certainly not equals.
But I also know that the U.S. education establishment sometimes resorts to brainwashing and bullying. One of my children was once given a two-part homework assignment: 1) go through your family’s kitchen cupboards, identify all products and packages that are harmful to the environment, and report back to class and 2) get all family members to sign an environmentalist loyalty oath.
The education establishment warns that if we don’t teach our children “the scientific method” we will become a nation of science illiterates. Let me tell you a little story. Once upon a time the majority of scientists believed in something called “the luminiferous ether.” It was a mysterious form of matter that permeated all of space—and helped explain how electromagnetic waves propagate through a vacuum. Some great scientific work was done based on this assumption—even though it was later proved false.
The lesson is that scientists must remain free to embrace any hypothesis as long as it does not deny specific indisputable facts or make clearly contradictory assertions. We need more free exchange of ideas—not less.
UPDATE: May 5, 2008 - 9:50am Eastern:
Stein did not help his cause when he told Trinity Broadcasting Network "...science leads you to killing people." A more popular view is that science is inherently neither good nor bad. I go further: science is inherently good but can be corrupted and exploited for evil purposes.
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