Pathological science

From Academic Kids

Pathological science is a term created by the Nobel Prize-winning chemist Irving Langmuir during a colloquium at the Knolls Research Laboratory, December 18, 1953. Langmuir used the term to describe ideas that would simply not "go away", long after they were given up on as wrong by the majority of scientists in the field. The term is semantically loaded, and has often been taken as a personal insult implying utter foolishness in the target. It involves self-deception amongst a larger number of participants and as such, is fundamentally different from conscious scientific fraud.

Critics of the concept argue that it fails to offer criteria that distinguish lasting discoveries (and other scientific studies) from mere fads and fallacies and that it could be applied to many revolutionary discoveries of the past. Critics also urge others to abandon the phrase.


Pathological science

Pathological science, as defined by Langmuir, is a psychological process in which a scientist, originally conforming to the scientific method, unconsciously veers from that method, and begins a pathological process of wishful data interpretation. Criteria for pathological science are:

  • The maximum effect that is observed is produced by a causative agent of barely detectable intensity, and the magnitude of the effect is substantially independent of the intensity of the cause.
  • The effect is of a magnitude that remains close to the limit of detectability, or many measurements are necessary because of the very low statistical significance of the results.
  • There are claims of great accuracy.
  • Fantastic theories contrary to experience are suggested.
  • Criticisms are met by ad hoc excuses.
  • The ratio of supporters to critics rises and then falls gradually to oblivion.


Langmuir discussed the issue of N-rays as an example of pathological science, one that is universally regarded as pathological.

The discoverer, René-Prosper Blondlot, was working on X-rays (as were many physicists of the era) and noticed a new visible radiation that could penetrate aluminium. He devised experiments in which a barely visible object was illuminated by these N-rays, and thus became considerably "more visible".

After a time another physicist, Robert W. Wood, decided to visit Blondlot's lab, where he had since moved on to the physical characterization of N-rays. The experiment passed the rays from a 2 mm slit through an aluminium prism, from which he was measuring the index of refraction to a precision that required measurements accurate to within 0.01 mm.

Wood asked how it was possible that he could measure something to 0.01 mm from a 2 mm source, a physical impossibility in the propagation of any kind of wave. Blondlot replied, "That's one of the fascinating things about the N-rays. They don't follow the ordinary laws of science that you ordinarily think of."

Wood then asked to see the experiments being run as usual, which took place in a room required to be very dark so the target was barely visible. Blondlot repeated his most recent experiments and got the same results—despite the fact that Wood had reached over and covertly removed the prism.

Other examples

Langmuir also covered a small number of other examples of pathological science in his original speech, but most of these have since faded from discussion. However, a number of newer examples have since been offered.

Certainly the example of polywater is one of pathological science. In this case, however, the problem spread beyond a single lab; largely as a result of much better publishing and international talks, polywater experiments were being carried out around the world. Moreover polywater made some scientific sense as, although unlikely, it was certainly within the realm of possibility. With considerably more time and energy invested in the concept, polywater took much longer to die than N-rays, which basically had a single supporter.

A more recent example is cold fusion, the very mention of which continues to spark debate. However, the historical record is clear: skeptics claim that cold fusion shows exactly the same sort of research patterns as polywater did in the 1960s. After the announcement, a huge number of research projects were reportedly started to investigate the effect, but the vast majority turned up nothing. However, cold fusion researchers point out it is difficult to estimate how many of these projects really were started, or to evaluate what was actually done in them, because most were not published in the peer-reviewed literature or conference proceedings. A database of papers maintained by D. Britz and E. Storms shows that by the end of 1990, 881 papers were published, and most of these reported positive results. In September 1990, F. Will at the National Institute for Cold Fusion compiled a list of 92 groups at universities and national laboratories reporting positive results [Mallove, p. 247]. The Britz/Storms database increased to over 3,200 papers by May 2005 (counting mostly papers in English, not Italian, Japanese or Chinese).

Skeptics claim that only a few experiments were positive and became causes célèbres and justified further research. Skeptics say that to date cold fusion has not completely "died", but they claim there is complete lack of repeatability and no clear evidence that the effect exists. Cold fusion researchers, on the other hand, claim that hundreds of positive results were reported, and that repeatability ranges from 50% to nearly 100%, which is better than it is for some other well established fields of science. They point out that the peer-reviewed literature includes many results at a high signal to noise ratios, sigma 90 and above, meaning this is very clear, positive evidence.

Furthermore, cold fusion researchers say the pattern of their results do not resemble those of polywater. Langmuir listed ten rules of thumb, but cold fusion does not meet any of them:

1. "The maximum effect that is observed is not of barely detectable intensity . . ." Cold fusion heat has been measured at sigma 90. In 1990 tritium was measured at 60 times background, and in some subsequent experiments it was several million times background, and beyond the upper detection limit of the instruments.

2. "The effect is of a magnitude that remains close to the limit of detectability." Many cold fusion results are far above the limit of detectability.

3. "There are claims of great accuracy." This is not the case with cold fusion. Researchers use ordinary, off-the-shelf equipment and claim only ordinary levels of accuracy. In some cases, such as at Mitsubishi, extremely expensive and accurate equipment has been made, but the levels of heat, gamma rays and transmutations these researchers observe could easily be detected with ordinary instruments.

4. "Fantastic theories contrary to experience are suggested." Theories have not been proposed. Cold fusion is based on experimental evidence, not theory.

5. "Criticisms are met by ad hoc excuses." Criticisms of the experiments have only been published in one peer-reviewed paper, which was answered by the authors in detail. [1] (

6. "The ratio of supporters to critics rises and then falls gradually to oblivion." This ratio is impossible to measure, but in any case, it may well reflect political power or the ability to influence public opinion, rather than the scientific validity of the claims.

J. Piel, the late editor of the Scientific American, added another criterion to Langmuir's list. He wrote that science is pathological when "the precise physical mechanism is not fully understood." (Scanned image of his letter ( This would broaden the definition of pathological science to include nearly every discovery, since very few discoveries were fully understood when they were first made.

Scientific theories that are not pathological science

Lysenkoism is named after Trofim Lysenko and refers to a period of Soviet science in which political ideas superseded scientific rigour. Lysenko was an influential political figure, but his ideas were devoid of scientific merit; many scientists of the time were forced into publicly recanting politically unacceptable ideas such as evolution (those that refused were imprisoned).

The theory of Plate Tectonics was proposed in 1912 by Alfred Wegener but not taken seriously by geologists until well into the 1960s. While it sounded fantastic in the first half of the last century it did make clear predictions about the movement of the continental plates, and as soon the mechanisms driving continental drift and seafloor spreading were elucidated, the theory gained wide acceptance.


Langmuir was at one time a supporter of the cubical atom, a theory that later was abandoned in favor of the Bohr atom. A comparison of this incorrect theory with, for instance, N-rays, can give insight into the meaning of pathological science.

Whenever a subject is branded as pathological science, its defenders flock to its defense. In general the arguments claim that in the past "people didn't consider <<effect xxx>> to be real, but it was later proved to be true". However these arguments tend to miss the point. The issue is not whether or not an effect actually exists, nor whether or not people "believe in it"; the issue is how the support for the claim is given.

Nevertheless the term remains a difficult one to use. Most of the problem appears to be the use of the word "pathological", which to many people implies mental illness. A more neutral term may be seen as more acceptable.

Critics sometimes assert that a pathological science can only be shown to be one in retrospect. Supporters of Langmuir's idea, however, point to explicit principles, such as the first three cited above. The radical and inexplicable discovery of radioactivity, for instance, could never have been classed as pathological science precisely because the observations were not at the limit of detection and could be easily reproduced. To give a modern example, many people consider cold fusion to be pathological, yet research continues. The possibility certainly exists that one of these experiments will suddenly prove the effect exists—but the same is true for N-rays. In fact, the test of pathological science is not whether a reported discovery turns out to be true, but the nature of the claims and the evidence for them.

Mainstream sciences have failed historically to approve of certain sciences till years later and inappropriately label them as pathological. It is claimed that the following are examples of scientific work that have been inappropriately described as either pathological science or incorrect:

See also

External links and bibliography



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