August 28, 1992
Science warns me to be careful how I adopt a view which jumps with my preconceptions, and to require stronger evidence for such beliefs than for one to which I was previously hostile.
Thomas Huxley, 1860
Most creative work starts with an act of imagination -- fantasy, pure and simple. Imagination alone, untarnished by reality, can get you a ticket to the funny farm. A religious prophet can make it on just imagination if he can get enough people to go along with him. For an artist to create a work of art, music or literature, the imagination has to be combined with craftsmanship. Both the craftsmanship and the imagination are essential; one without the other doesn't accomplish much.
Since science deals with the truth, there is a third essential element in scientific research: verification. No matter how great the imagination and craftsmanship is, if it isn't true it is worthless. Since scientists are human, they may fall into the same psychological pitfalls as anyone else.
The Greek philosopher and scientist Aristotle(384-322 B.C.) made some important observations. He also made a number of unfounded speculations which, with the help of a church which made everything that he said an article of faith, retarded science and medicine for centuries.
Plato(427-347 B.C.), Aristotle(384-322 B.C.), and Galen (130-200A.D.) made observations on the heart. Their observations were mixed with speculation and philosophy. None of them actually understood what the heart did. The Spanish physician Michael Servetus(1511-1553) may have understood the function of the heart, but he was burned at the stake for heresy and his writings destroyed. It took William Harvey(1578-1657) to show how the heart, lungs and blood vessels functioned. Harvey's publication, On TheMovement of the Heart, is a model of clarity and erudition. It is recommended reading for anyone going into science or medicine.
In 1926, Johannes Fibiger of Denmark was awarded the Nobel Prize in Medicine for discovering that roundworms cause cancer of the stomach in rats. His work could not be verified -Fibiger was mistaken. The scientific world and the Nobel committee were justifiably embarrassed by the incident and they have been very cautious ever since about rushing to judgment, particularly in matters concerned with cancer.
I was involved in a similar incident: the case of Sir Ronald Aylmes Fisher versus Gregor Mendel. Gregor Mendel discovered the basic laws of genetics in the mid 1800s. His work was ignored until the turn of the century, when it was rediscovered and its brilliance acknowledged. It changed, forever, the way that biological research was done.
R.A.Fisher was a mathematical geneticist who did some highly acclaimed work on experimental method, particularly as it applied to genetics. He was an acknowledged leader in mathematical genetics. He developed ways of dealing with unknown biases in experiments and statistical tests that can be used with such experiments.
Fisher decided that he could detect faked data by examining their probability and he decided that Mendel's data were just too good to be true. He tested Mendel's combined data with a test of goodness-of-fit(a test that tells you how well an experiment and your theory match) called Chi Square and found the probability value extremely high. In 1936 he published a paper in which he concluded that Mendel had falsified his data.
On the face of it, this seemed to me to be irrational. It is the equivalent of accusing someone of cheating because he draws a royal flush in poker.
Fisher had overlooked an important aspect of the Chi Square test. The test was designed to test whether a set of observations agree with a particular hypothesis. Therefore, every time that you do an experiment to test a particular hypothesis and the results agree with the hypothesis, the probability of the hypothesis being true increases. If enough experiments of the right kind are done, the probability approaches certainty. When using the Chi Square test, if the data are compatible with the theory, as Mendel's data were, and there are a number of experiments, the probability value would be expected to approach certainty. That's one way that theories are tested.
It is not unusual for a scientist to make a mistake. What is unusual is for a scientist as skilled as Fisher to make such an elementary error in the field in which he is the acknowledged expert. I can't imagine what blinded him to the truth --but it did happen.
It is easy to understand why Fisher's word would be accepted, particularly since it was supported by other equally formidable scientific authorities. Few scientists questioned it, and many still believe that Fisher was correct despite the crystal clear demonstration of his error.
If Fisher didn't understand what Chi Square was all about, perhaps the very structure of science is shaky. I don't believe that. It merely shows what we have known all along; that even the greatest can be wrong, and we would do well to accept things very cautiously, particularly when they are at variance with common sense.
Return to the Science Home Page
Return to Ira's Home Page