Controversy in Chemistry: How Do You Prove a Negative?- The Cases of Phlogiston and Cold Fusion
By Jay A. Labinger* and Stephen J. Weininger*

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Angewandte Chemie International Edition
2005, 44, 1916 -1922
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Case 2: The Short Life (but Longer Afterlife) of Cold Fusion**

Our previous essay dealt with a recent controversy, that of bond-stretch isomerism, which was relatively unfamiliar even to the majority of practicing chemists, and completely unknown outside their ranks. The roughly contemporaneous case of cold fusion was entirely the opposite. For several months in 1989 it was one of the hottest topics around-not just in scientific journals, but also in newspapers, popular magazines, TV shows, etc. We can think of no chemistry story that has attained comparable visibility. Indeed, how it played out in the public eye would merit a fascinating and valuable examination in its own right, but one that would far exceed the scope of this Essay. Nor do we have space to consider the claims and counterclaims in any detail; in any case, most readers are probably fairly familiar with at least the basic outline. We present below a very brief summary. For those who want to know more, several full-length book accounts, written from a variety of perspectives (including scientist-nonbeliever,[28] scientist-agnostic/skeptic,[29] scientist/science writer-nonbeliever,[30] scientist/science writer-believer,[31] and science writer-nonbeliever[32]) were published within the first few years. There are also a number of internetbased bibliographies which can easily be located on-line.

The controversy opened in March 1989, when University of Utah electrochemists Stanley Pons and Martin Fleischmann held a press conference to announce that electrolysis of D2O at a palladium electrode produced anomalous effects, including liberation of energy in excess of the input-in one case to such an extreme extent as to melt the Pd cathode and destroy the apparatus. A publication appearing shortly afterwards (but submitted prior to the press conference) provided some details and also reported neutron fluxes, g-rays at the right energy to indicate proton- neutron reactions, and accumulation of tritium in the electrolyte.[33] Related, but much less dramatic, findings (many fewer neutrons, no excess heat) were published around the same time by Steve Jones, a physicist at Brigham Young University.[34] (The two research groups were aware of each other's work; concerns over priority issues-patent rights in particular-no doubt prompted the unorthodox publication-by-press-conference and substantially set the tone for ensuing developments.) The authors concluded that nuclear fusion, which had been somehow catalyzed within the Pd lattice, was the only possible explanation for these observations.

The clear potential importance of such a discovery, coupled with the apparent experimental simplicity, inspired many to attempt replication. Within a matter of weeks a number of positive findings were announced (mostly by press release, like the original), including excess heat (Texas A&M, Stanford), neutrons (Georgia Tech), and tritium (Washington, a different group at Texas A&M). A special session on cold fusion at the April 1989 ACS national meeting attracted an audience of around 7000 (mostly) enthusiastic chemists. Almost immediately, though, strong skepticism set in, as several of the highly publicized "confirmations" were retracted, with explanations of the experimental problems responsible. A special session at the American Physical Society meeting at the beginning of May featured a number of negative presentations; one in particular (by Nate Lewis, subsequently published[35]) reported his research group's inability to detect any excess heat, possible experimental reasons why one might (erroneously) detect excess heat, and a deconstruction of the assumptions used by Pons and Fleischmann that, he argued, led to deducing excess heat evolved from unconvincing data. Later in May, a publication appeared demonstrating that the claimed g-ray signature was artifactual.[36]

Over the next year or so the controversy continued, as further positive as well as negative results appeared regularly. A Department of Energy (DOE) panel investigated the topic during the summer, and issued its report-strongly negative-in October. In August 1989 the National Cold Fusion Institute (NCFI) was inaugurated in Salt Lake City, funded by the state of Utah (after federal support was refused). The First Annual Conference on Cold Fusion was held there in March 1990; the participants were primarily (by design) those with positive findings to report. In any case the majority of critics had concluded there was little left that needed to be criticized, and ceased paying much attention. By late 1990 both Pons and Fleischmann had left Utah, and the NCFI closed the following June. The cold fusion controversy was effectively over.

But not cold fusion. Research has continued at a moderate level of activity right up to the present day. A good deal of the work has been published in nonmainstream journals (some created for the purpose) or electronically; but occasionally papers have appeared in prestigious locations, such as the 1993 paper by Pons and Fleischmanns on calorimetry, which was accepted by Physics Letters A.[37] This publication merits notice on further grounds: it reports what appears to be the last joint experimental work by Fleischmann and Pons on cold fusion. Perhaps more importantly, it is one of the last reports to be formally challenged on technical grounds by a cold fusion skeptic.[38] Subsequent claims have been almost completely ignored by the scientific mainstream, and the popular media has generally followed suit, with a few exceptions. Compilations of this work may be found on a number of websites, notably the LENR-CANR (low energy nuclear reactions/ chemically assisted nuclear reactions) site,[39] which features bibliographic material and summaries, written from the strong proponents' point of view. A quite different (and intriguing) perspective may be found in a recent book by the sociologist of science Bart Simon, who proposes a new model for understanding how and why research persists beyond the point where the vast majority of the community considers the field finished: he calls it "Undead Science".[40]

Two somewhat less fanciful, but rather contradictory, conceptual models have been offered for the consideration of scientific controversies: one from an internal point of view and one more external. In fact they both seem to fit the cold fusion saga pretty well. The first is that of "pathological science", first described by Irving Langmuir in a 1953 lecture (a transcription was republished in Physics Today in 1989[41]) and subsequently reprised and updated by Denis Rousseau.[42] According to Rousseau, pathological science has three fundamental characteristics:

  1. Observed effects are near the limits of detectability and/or statistically marginally significant; their magnitudes cannot be controlled in any systematic way by varying experimental parameters.
  2. Incompatibility with accepted theories or principles is readily ignored.
  3. Investigators avoid carrying out critical, potentially disconfirming experiments, and refuse to accept any such experiments carried out by others as conclusive.

Rousseau argued that all three applied to Pons and Fleischmann (the other two cases he examined were "polywater" and Benveniste's "infinite dilution"), in which he called particular attention to the complete lack of correspondence between the excess heat claimed and the levels of nuclear byproducts detected (point 2), and the failure to perform any control experiments with ordinary water (point 3). The first point applies to the question of excess heat itself (although Rousseau does not specifically comment on that): even in the original paper[33] some of the data (Table 2) appear to show effects varying inversely with input, and subsequent analysis established that many of the most striking claims were actually tiny numbers inflated by dubious assumptions.[ 35]

A quite different perspective has been proposed by the sociologist of science Harry Collins. The "Experimenter's Regress", which was introduced in a discussion of the search for gravity waves, argues that it is impossible to separate questions about the existence or non-existence of a novel phenomenon from questions about the validity of the experiments designed to detect it:

"When the normal criterion--successful outcome- is not available, scientists disagree about which experiments are competently done.
Where there is disagreement about what counts as a competently performed experiment, the ensuing debate is coextensive with the debate about the proper outcome of the experiment".[43]

Clearly this may be applied to cold fusion (as Collins and a colleague did[44]): any negative finding can always be (and has been) challenged as incorrectly performed, such as claims that the wrong kind of electrode was used, etc.

The fact that these dueling descriptors are both operative has much to do with the continued survival of cold fusion research-if only as a ghostly entity, as Simon would have it. How should we view the more recent findings in light of the earlier, substantially discredited work? Pons and Fleischmann, and others, made some rather major errors that led to reports of large effects-excess heat exceeding 1000%, high levels of neutrons or tritium-so a skeptic comfortably concludes that the generally much smaller effects now claimed are the result of more subtle errors. Conversely, proponents can reasonably argue that their later experimental designs do take previous criticisms into account, and should not be automatically assumed to be tainted by the same old mistakes; but they never get the opportunity to defend themselves, since nobody even bothers to criticize them. A (rather plaintive) letter to this effect, published in Chemical & Engineering News in 2003,[45] elicited no response at all. As Simon comments:

"No matter what kinds of new experiments and data CF researchers present, their critics (if even listening) always drag them back to debates from 1989. There seems to be no escape . Their collective identity as a group as well as their scientific practice is organized to a large degree around reclaiming scientific legitimacy by constantly revisiting the criticisms of 1989-1990. In part they have no choice, since there are few extant criticisms of work after 1990 that they can address".[46]

Another factor in the post-mortem survival of cold fusion has been its decidedly chimerical nature. Which of the various phenomena that have been reported in the context of cold fusion- excess heat, neutrons, tritium, X-rays, grays, helium, even transmutation[47]- are fundamental to whatever (if anything) is going on? At least some of these reports are indisputably erroneous, but what does that imply about others? For example, the philosopher of science William McKinney, in arguing that one can escape from the "Experimenter's Regress" on the basis of objective analysis of experiments, suggested that the unequivocal demonstration of the artifactual g-ray signature (thus undermining the claim for neutrons) was the real "knockout blow" for cold fusion.[48] However, cold fusion researchers are committed to no theory, so (on their account) excess heat need not be tied to neutrons. Since nobody has seriously claimed to understand the phenomena on the basis of any unifying theory, there need not be any real links between the various types of phenomena studied. From a strictly logical point of view, every individual experiment would need to be evaluated on its own merits: if one set of claims is debunked to everyone's satisfaction, that does not necessarily disprove another.

Indeed, one of the more recent studies (by the above-cited letter-writer Melvin Miles) reports detecting 4He along with excess heat in more or less commensurate amounts, if it is assumed that the heat is produced by fusion of two deuterons to produce 4He and energy [Eq. (2)]. Furthermore, he claims that although the generation of excess heat is not always reproducible, the two phenomena correlate well, and the long-demanded control experiment was performed: light-water experiments exhibit neither excess heat nor 4He.[49] Of course, in "standard" D+D fusion, Equation (2) represents a very lowprobability pathway compared to reactions that generate neutrons and tritium,[50] and one would also need to explain why the energy liberated shows up entirely as heat rather than radiation (and many more things besides). But if one is willing to accept the possibility of some kind of nonstandard nuclear process going on within the Pd lattice (a big if for many, but one that does not seem to have much troubled cold fusion researchers), there are no apparent a priori grounds for dismissing these and other findings. They might well be subject to criticism on a variety of experimental grounds; but as noted above, work from the last ten years or more has received little, if any, scrutiny at all.

D + D --> 4He + [gamma] (23.77MeV)    (2)

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. Under these circumstances, the DOE has decided to carry out another review, which is underway at the time of writing (summer 2004). From the range of comments made in response to that announcement,[51] though, it seems most unlikely that their report will settle matters:

"There are quite a few people who are putting their time into this. They are working under conditions that are bad for their careers. They think they are doing something that may result in some important new finding. I think scientists should be open minded. Historically, many things get overturned with time."

"The critical question is, How good and different are [the cold fusion researchers'] new results? If they are saying, 'We are now able to reproduce our results, that's not good enough. But if they are saying, 'We are getting 10 times as much heat out now, and we understand things,' that would be interesting. I don't see anything wrong with giving these people a new hearing."

"I think a review is a waste of time. But if you put together a credible committee, you can try to put the issue to bed for some time. It will come back. The believers never stop believing."

There are clear differences between our two cases: whereas the phlogiston controversy involved choosing the best theoretical framework to rationalize a set of experimental observations, with cold fusion there are essentially no theoretical frameworks among which to choose. Instead we have a set of observations that cannot be rationalized in terms of existing standard theory, and need to decide whether they (or some fraction thereof) are real anomalies that require new ideas, or mere mistakes. The majority of the scientific community has (explicitly or implicitly) opted for the second interpretation, just as the majority decided against phlogiston at the end of the 18th century. But the minority positions, then and now, were sustained for a considerable period. It is easy, but (as we have tried to show) much too simplistic, to invoke irrationality to explain this persistence of heterodoxy. Instead, these two cases illustrate that, once the human imagination has conceived an idea, it can sometimes be very difficult to prove its non-existence.



* Dr. J. A. Labinger
Beckman Institute
California Institute of Technology, 139-74
Pasadena, CA 91125 (USA)
Fax: (+1) 626-449-4159
E-mail: jal@its.caltech.edu

Prof. S. J. Weininger
Worcester Polytechnic Institute
Worcester, MA 01609-2280 (USA)
Fax: (+1) 508-831-5933
E-mail: stevejw@wpi.edu

[28] J. R. Huizenga, Cold Fusion: the Scientific Fiasco of the Century, University of Rochester Press, Rochester, 1992.
[29] N. Hoffman, A Dialogue on Chemically Induced Nuclear Effects: AGuide for the Perplexed about Cold Fusion, American Nuclear Society, La Grange Park, 1995.
[30] F. Close, Too Hot to Handle: The Race for Cold Fusion, Princeton University Press, Princeton, 1991.
[31] G. Mallove, Fire from Ice: Searching for the Truth Behind the Cold Fusion Furor, Wiley, New York, 1991.
[32] G. Taubes, Bad Science: The Short Life and Weird Times of Cold Fusion, Random House, New York, 1993.
[33] M. Fleischmann, S. Pons, J. Electroanal. Chem. 1989, 261, 301 - 308.
[34] S. E. Jones, E. P. Palmer, J. B. Czirr, D. L. Decker, G. L. Jensen, J. M. Thorne, S. F. Taylor, J. Rafelski, Nature 1989, 338, 737 - 740.
[35] N. S. Lewis, C. A. Barnes, M. J. Heben, A. Kumar, S. R. Lunt, G. E. McManis, G. M. Miskelly, R. M. Penner, M. J. Sailor, P. G. Santangelo, G. A. Shreve, B. J. Tufts, M. G. Youngquist, R. W. Kavanagh, S. E. Kellog, R. B. Vogelaar, T. R. Wang, R. Kondrat, R. New, Nature 1989, 340, 525 - 530; G. M. Miskelly, M. J. Heben, A. Kumar, R. M. Penner, M. J. Sailor, N. S. Lewis, Science 1989, 246, 793 - 796.
[36] R. D. Petrasso, X. Chen, K. W. Wenzel, R. R. Parker, C. K. Li, C. Fiore, Nature 1989, 339, 183 - 185.
[37] M. Fleischmann, S. Pons, Phys. Lett. A 1993, 176, 498 - 502.
[38] D. R. O. Morrison, Phys. Lett. A 1994, 185, 118 - 129.
[39] http://www.lenr-canr.org/.
[40] B. Simon, Undead Science: Science Studies and the Afterlife of Cold Fusion, Rutgers University Press, New Brunswick, 2002.
[41] I. Langmuir (Ed.: R. N. Hall), Physics Today 1989, 42, 36 - 48.
[42] D. L. Rousseau, Am. Sci. 1992, 80, 54- 63.
[43] H. M. Collins, Changing Order: Replication and Induction in Scientific Practice, University of Chicago Press, Chicago, 1992, p. 89.
[44] H. Collins, T. Pinch, The Golem: What Everyone Should Know About Science, Cambridge University Press, Cambridge, 1993, pp. 57 - 78.
[45] M. H. Miles, Letter to the Editor, Chem. Eng. News 2003, 81 (24 November), 6.
[46] Ref. [40], p. 217.
[47] Ref. [40], pp. 150-153.
[48] W. J. McKinney in A House Built on Sand: Exposing Postmodernist Myths about Science (Ed.: N. Koertge), Oxford University Press, Oxford, 1998, pp. 133 - 150.
[49] M. Miles, Correlation Of Excess Enthalpy And Helium-4 Production: A Review. Tenth International Conference on Cold Fusion, Cambridge, 2003. Available at http://www.lenr-canr.org/LibFrame1. html.
[50] Ref. [28], pp. 6-7.
[51] T. Feder, Phys. Today 2004, 57, 27 - 28.


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