Pathological science is an area of research where "people are tricked into false results ... by subjective effects, wishful thinking or threshold interactions."[1][2] The term was first used by Irving Langmuir, Nobel Prize-winning chemist, during a 1953 colloquium at the Knolls Research Laboratory.[3] Langmuir said a pathological science is an area of research that simply will not "go away"—long after it was given up on as "false" by the majority of scientists in the field. He called pathological science "the science of things that aren't so."[4][5]

Bart Simon lists it among practices pretending to be science: "categories ... such as ... pseudoscience, amateur science, deviant or fraudulent science, bad science, junk science, and popular science ... pathological science, cargo-cult science, and voodoo science."[6] Examples of pathological science include the Martian canals, N-rays, polywater, and cold fusion. The theories and conclusions behind all of these examples are currently rejected or disregarded by the majority of scientists.


Irving Langmuir coined the phrase pathological science in a talk in 1953.

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 (see the observer-expectancy effect and cognitive bias). Some characteristics of pathological science are:

Langmuir never intended the term to be rigorously defined; it was simply the title of his talk on some examples of "weird science". As with any attempt to define the scientific endeavor, examples and counterexamples can always be found.

Langmuir's examples

Fig. 6,7 from Prosper-René Blondlot: "Registration by Photography of the Action Produced by N Rays on a Small Electric Spark". Nancy, 1904.


Main article: N ray

Langmuir's discussion of N-rays has led to their traditional characterization as an instance of pathological science.[7]

In 1903, Prosper-René 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 "more visible". Blondlot claimed that N-rays were causing a small visual reaction, too small to be seen under normal illumination, but just visible when most normal light sources were removed and the target was just barely visible to begin with.

N-rays became the topic of some debate within the science community. After a time, American physicist Robert W. Wood decided to visit Blondlot's lab, which had moved on to the physical characterization of N-rays. An experiment passed the rays from a 2 mm slit through an aluminum 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 sabotaged the N-ray apparatus by removing the prism.[1][8]

Other examples

Langmuir offered additional examples of what he regarded as pathological science in his original speech:[9]

Later examples

A 1985 version[citation needed] of Langmuir's speech offered more examples, although at least one of these (polywater) occurred entirely after Langmuir's death in 1957:

Newer examples

Since Langmuir's original talk, a number of newer examples of what appear to be pathological science have appeared. Denis Rousseau, one of the main debunkers of polywater, gave an update of Langmuir in 1992, and he specifically cited as examples the cases of polywater, Martin Fleischmann's cold fusion and Jacques Benveniste's "infinite dilution".[14]


Main article: Polywater

Polywater was a form of water which appeared to have a much higher boiling point and much lower freezing point than normal water. During the 1960s, many articles were published on the subject, and research on polywater was done around the world with mixed results. Eventually it was determined that many of the properties of polywater could be explained by biological contamination. When more rigorous cleaning of glassware and experimental controls were introduced, polywater could no longer be produced. It took several years for the concept of polywater to die in spite of the later negative results.

Cold fusion

Main article: Cold fusion

In 1989, Martin Fleischmann and Stanley Pons announced the discovery of a simple and cheap procedure to obtain room-temperature nuclear fusion. Although there were many instances where successful results were reported, they lacked consistency and hence cold fusion came to be considered to be an example of pathological science.[15] Two panels convened by the US Department of Energy, one in 1989 and a second in 2004, did not recommend a dedicated federal program for cold fusion research. A small number of researchers continue working on the field.

Water memory

Main articles: Benveniste affair and Water memory

Jacques Benveniste was a French immunologist who in 1988 published a paper in the prestigious scientific journal Nature describing the action of very high dilutions of anti-IgE antibody on the degranulation of human basophils, findings which seemed to support the concept of homeopathy. Biologists were puzzled by Benveniste's results, as only molecules of water, and no molecules of the original antibody, remained in these high dilutions. Benveniste concluded that the configuration of molecules in water was biologically active. Subsequent investigations have not supported Benveniste's findings.

See also


  1. ^ a b Irving Langmuir, "Colloquium on Pathological Science," held at the Knolls Research Laboratory, December 18, 1953. A recording of the actual talk was made, but apparently lost, though a recorded transcript was produced by Langmuir a few months later. A transcript is available on the Web site of Kenneth Steiglitz, Professor of Computer Science, Princeton University. But see also: I. Langmuir, "Pathological Science", General Electric, (Distribution Unit, Bldg. 5, Room 345, Research and Development Center, P.O. Box 8, Schenectady, NY 12301), 68-C-035 (1968); I. Langmuir, "Pathological Science", (1989) Physics Today, Volume 42, Issue 10, October 1989, pp. 36–48
  2. ^ "Threshold interaction" refers to a phenomenon in statistical analysis where unforeseen relationships between input variables may cause unanticipated results. For example, see Dusseldorp, Voorjaarsbijeenkomst 2005 Archived 2011-07-24 at the Wayback Machine
  3. ^ "Langmuir's talk on Pathological Science". Princeton University Department of Computer Science. Retrieved 3 September 2013.
  4. ^ Park, Robert (2000). Voodoo Science: The Road from Foolishness to Fraud. Oxford University Press. p. 41. ISBN 0198604432.
  5. ^ Langmuir's contribution followed the first edition (1952) of Martin Gardner's book Fads and Fallacies in the Name of Science (Dover, 1957). Gardner cited especially the "magnificent collection of crank literature" in the New York Public Library.
  6. ^ Bart Simon, Undead Science: Science Studies and the Afterlife of Cold Fusion (2002) ISBN 0813531543. Simon refers to: Thomas F. Gieryn, Cultural Boundaries of Science: Credibility on the Line (1999) University of Chicago Press, ISBN 0226292622
  7. ^ Helge Kragh (1998). "Social constructivism, the Gospel of Science, and the Teaching of Physics". In Michael R. Matthews (ed.). Constructivism in science education: a philosophical examination (illustrated ed.). Springer. p. 134. ISBN 978-0792350330.
  8. ^ Wood, R.W. (29 September 1904). "The N-Rays". Nature. 70 (1822): 530–531. Bibcode:1904Natur..70..530W. doi:10.1038/070530a0. S2CID 4063030. After spending three hours or more in witnessing various experiments, I am not only unable to report a single observation which appeared to indicate the existence of the rays, but left with a very firm conviction that the few experimenters who have obtained positive results, have been in some way deluded. A somewhat detailed report of the experiments which were shown to me, together with my own observations, may be of interest to the many physicists who have spent days and weeks in fruitless efforts to repeat the remarkable experiments which have been described in the scientific journals of the past year.
  9. ^ "transcript of speech".
  10. ^ For a review and bibliography, see Hollander and Claus, J. Opt. Soc. Am., 25, 270–286 (1935).
  11. ^ F. Allison and E.S. Murphy, J. Am. Chem. Soc., 52, 3796 (1930). (b) F. Allison, Ind. Eng. Chem., 4, 9 (1932). (c) S. S. Cooper and T. R. Ball, J. Chem Ed., 13, 210 (1936), also pp. 278 and 326. (d) M. A. Jeppesen and R. M. Bell, Phys. Rev., 47, 546 (1935). (e) H. F. Mildrum and B. M. Schmidt, Air Force Aero Prop. Lab. AFAPL-TR-66-52 (May 1966).
  12. ^ Eric Scerri (2009), "Finding francium", Nature Chemistry, In Your Element, 670 (1): 670, Bibcode:2009NatCh...1..670S, doi:10.1038/nchem.430, PMID 21378961, Dozens of papers were published on this effect, including a number of studies arguing that it was spurious. These days the Allison effect is often featured in accounts of pathological science, alongside the claims for N-rays and cold fusion
  13. ^ Krippner, Stanley; Friedman, Harris L. (2010). Debating Psychic Experience: Human Potential Or Human Illusion? (illustrated ed.). ABC-CLIO. p. 151. ISBN 978-0313392610. Classic cases of pathological science, such as the alleged "discovery" of canals on Mars, N-rays, polywater, cold fusion, and so on are all testament to the fact that dozens of papers can appear in the scientific literature attesting to the reality of the phenomena, which turn out to be entirely illusory.
  14. ^ D. L. Rousseau (January–February 1992). "Case Studies in Pathological Science: How the Loss of Objectivity Led to False Conclusions in Studies of Polywater, Infinite Dilution and Cold Fusion". American Scientist. 80: 54–63.
  15. ^ Labinger JA, Weininger SJ (2005). "Controversy in chemistry: how do you prove a negative? – the cases of phlogiston and cold fusion". Angew Chem Int Ed Engl. 44 (13): 1916–1922. doi:10.1002/anie.200462084. PMID 15770617. So there matters stand: no cold fusion researcher has been able to dispel the stigma of 'pathological science' by rigorously and reproducibly demonstrating effects sufficiently large to exclude the possibility of error (for example, by constructing a working power generator), nor does it seem possible to conclude unequivocally that all the apparently anomalous behavior can be attributed to error.