The Astrophysics Spectator
The Astrophysics Spectator
As I watch the rolling disaster overtake Dan Rather and CBS news over the forged documents that Rather presented as evidence of a young George Bush not fulfilling his duty in the National Guard, I see a side of human nature that often surfaces in science: our need to cling to our world view. We each interpret what we see with an internal world view that we have constructed for ourselves. When we see data that conforms to our world view, we trust that the data is accurate, and when we see data that conflicts with our world view, we tend to discount the data.1
Because of his world view, Dan Rather accepted the documents without question; in his mind President Bush was irresponsible as a young man, and the documents backed up this belief. The documents, however, clearly are forgeries written on a computer with the Microsoft Word program, and not on a 1972 vintage typewriter. Rather could not recognize the small-font superscripted "th", which is standard feature of modern word processors, but an uncommon feature of typewriters of 1972, as a warning flag of a forgery. He did not recognize the automatic centering and proportional spacing of the header information that is trivial for a word processor, but extremely difficult on even the most expensive 1970s era typewriter. He failed to check the status of the man who, according to the memos, was exerting pressure on behalf of Bush; that man had retired 18 months earlier, and was therefore in no position to pressure anyone. He ignored the experiments that precisely reproduced the CBS memos using Microsoft Word with the default settings. The memos are obvious forgeries, but Dan Rather believed them, because they conformed to his world view.
When confronted by the avalanche of criticism from writers on the World Wide Web, in main stream newspapers, and competing television networks, Rather's reaction was to defend the data, first last Friday night, and again last Monday night. To Rather, what is suspect is the evidence that the memos are forgeries, because that evidence conflicts with his world view. A well-known joke in the science community speaking to this very human tendency is that science advances when the current generation dies.
Last year the American Astronomical Society held its summer meeting here in Nashville. At that meeting I fell into conversation with an old friend. He told me that he analyzed some data from an experiment, and that one of the data points was not in line with what he expected, so he threw it out under the assumption that it was a spurious data point. Now, bad data points are not uncommon, but the data point must be discarded for reasons other than that the result is not what is expected. Of course, my friend accepted as valid the remaining data points, which behaved as he expected.
On several occasions I have seen scientists refuse to change their view of the world when presented with evidence that counters their beliefs. One incident in particular stands out in my memory. A controversy I was a part of concerned the source of gamma-ray bursts.2 Are gamma-ray bursts emitted by neutron stars within the Milky Way Galaxy,3 or are they emitted by objects in the most distant galaxies? From the late sixties to the early 1990s, the neutron star theory was widely-accepted, but the observation of gamma-ray bursts by instruments on NASA's Compton Gamma-Ray Observatory (CGRO) showed that the gamma-ray burst sources were not confined to the galactic plane, as expected for the neutron star theory. The most likely explanation for the observation was that the sources of gamma-ray bursts were in distant galaxies. I remember have dinner during a conference on gamma-ray bursts with several friends who, like myself, had studied the neutron star theory for many years. I was convinced that the theory was dead, but others at the table still held out hope. At one point, one of my friends exclaimed "I just feel in my bones that gamma-ray bursts are coming from neutron stars!"
One of the goals of a scientific education is to overcome these innate tendencies. But few people, even those of us trained to be objective, are able to break out of our world view without a struggle. My friends had a world view developed over many years of research on neutron stars, and so they were emotionally invested in the neutron star theory for gamma-ray bursts. The deepest emotional investment is in theories that we have grown up with.
The best example of this is general relativity. This theory correctly describes the motion of the planets, particularly of the planet Mercury, and of light in the weak gravitational field around the Sun. However, the theory has never been tested in the strong field regime. Despite this, it has been the standard theory for strong gravitational fields for many decades; the black hole is the object in general relativity with the strongest gravitational field,4 and scientists constantly speak of objects as being confirmed black holes, but in fact there is no evidence for their existence. Belief in the existence of black holes is an act of faith, a belief that general relativity is correct in regimes that have not been tested. How would the scientific community react if an experiment contradicted general relativity in this regime? I suspect that it would take years and many confirmations before the scientific community accepted the results. Some members of the community would never accept the results.
This clinging to dead theories is the mechanism driving revolutionary change in science. In his discussion of scientific revolution, Thomas Kuhn in The Structure of Scientific Revolutions stated that a community adheres to its world view, which he called a paradigm, while evidence invalidating that world view accumulates, until the mass of evidence against the world view is overwhelming, and the community can no longer defend its position. At this point a revolution occurs, what Kuhn called a paradigm shift, and the community adopts a new world view that is consistent with the new data. This happened eventually with the theory for the origin of gamma-ray burst, this may happen with general relativity when new experiments are conducted, and it will happen at CBS news. The only question is who will be left clinging to his old world view until his death?
Jim Brainerd
1 One of the best discussions I know of about the biases caused by our world view is The Psychology of Intelligence Analysis by CIA officer Richard J. Heuer.
2 A gamma-ray burst is an event seen by satellites. It is a massive increase in the gamma-ray flux from a specific location on the sky that can last from a tenth of a second to a thousand seconds. They are produced by supernovae in distant galaxies.
3 A neutron star is a star with an extremely high density. It has a mass of between one to three solar masses, and it has a radius of around 15 km. A neutron star is the remains of a star that has undergone a supernova.
4 A black hole is the gravitational field produced by a point mass. Black holes are characterized by an event horizon at a characteristic distance from the point mass. Inside of the event horizon, light cannot escape, so objects that fall through the event horizon are unable to affect objects outside of the event horizon. Black holes are an unavoidable feature of Einstein's general theory of relativity.
