A case of Kuhn, quasicrystals & communication – Part I

Dan Shechtman’s discovery of quasi-crystals, henceforth abbreviated as QCs, in 1982 was a landmark achievement that invoked a paradigm-shift in the field of physical chemistry.

However, at the time, the discovery faced stiff resistance from the broader scientific community and an eminent chemist of the time. Such things made it harder for Shechtman to prove his findings as being credible, but he persisted and succeeded in doing so.

We know his story today because of its fairly limited coverage in the media, and especially from the comments of his peers, students and friends; its revolutionary characteristic was well reflected in many reports and essays.

Because such publications indicated the onset of a new kind of knowledge, what merits consideration is if the media internalized Thomas Kuhn’s philosophy of science in the way it approached the incident.

Broadly, the question is: Did the media reports reflect Kuhn’s paradigm-shifting hypothesis? Specifically, in the 1980s,

  1. Did science journalists find QCs anomalous?
  2. Did science journalists identify the crisis period when it happened or was it reported as an isolated incident?
  3. Does the media’s portrayal of the crisis period reflect any incommensurability (be it in terms of knowledge or communication)?

Finally: How did science journalism behave when reporting stories from the cutting edge?

The Structure of Scientific Revolutions

Thomas S. Kuhn’s (July 18, 1922 – June 17, 1996) book, The Structure of Scientific Revolutions, published in 1962, was significantly influential in academic circles as well as the scientific community. It introduced the notion of a paradigm-shift, which has since become a principal when describing the evolution of scientific knowledge.

Thomas Kuhn, Harvard University, 1949

Kuhn defined a paradigm based on two properties:

  1. The paradigm must be sufficiently unprecedented to attract researchers to study it, and
  2. It must be sufficiently open-ended to allow for growth and debate

By this definition, most of the seminal findings of the greatest thinkers and scientists of the past are paradigmatic. Nicholas Copernicus’s De Revolutionibus Orbium Coelestium (1543) and Isaac Newton’s Philosophiae Naturalis Principia Mathematica (1687) are both prime examples that illustrate what paradigms can be and how they shift perceptions and interests in the subject.

Such paradigms, Kuhn said (p. 25), work with three attributes that are inherent to their conception. The first of the three attributes is the determination of significant fact, whereby facts accrued through observation and experimentation are measured and recorded more accurately.

Even though they are the “pegs” of any literature concerning the paradigm, activities such as their measurement and records are independent of the dictates of the paradigm. Instead, they are, in a colloquial sense, conducted anyway.

Why this is so becomes evident in the second of the three foci: matches of fact with theory. Kuhn claims (p. 26) that this class of activity is rarer in reality, where predictions of the reigning theory are compared to the (significant) facts measured in nature.

Consequently, good agreement between the two would establish the paradigm’s robustness, whereas disagreement would indicate the need for further refinement. In fact, on the same page, Kuhn illustrates the rarity of such agreement by stating

… no more than three such areas are even yet accessible to Einstein’s general theory of relativity.

The third and last focus is on the articulation of theory. In this section, Kuhn posits that the academician conducts experiments to

  1. Determine physical constants associated with the paradigm
  2. Determine quantitative laws (so as to provide a physical quantification of the paradigm)
  3. Determine the applications of the paradigm in various fields

In The Structure, one paradigm replaces another through a process of contention. At first, a reigning paradigm exists that, to an acceptable degree of reasonableness, explains empirical observations. However, in time, as technology improves and researchers find results that don’t quite agree with the reigning paradigm, the results are listed as anomalies.

This refusal to immediately induct the findings and modify the paradigm is illustrated by Kuhn as proof toward our expectations clouding our perception of the world.

Instead, researchers hold the position of the paradigm as fixed and immovable, and attempt to check for errors with the experimental/observed data. An example of this is the superluminal neutrinos that were “discovered”, rather stumbled upon, at the OPERA experiment in Italy that works with the CERN’s Large Hadron Collider (LHC).

When the experiment logs from that fateful day, September 23, 2011, were examined, nothing suspicious was found with the experimental setup. However, despite this assurance of the instruments’ stability, the theory (of relativity) that prohibits this result was held superior.

On October 18, then, experimental confirmation was received that the neutrinos could not have traveled faster than light because the theoretically predicted energy signature of a superluminal neutrino did not match with the observed signatures.

As Kuhn says (p. 77):

Though they [scientists] may begin to lose faith and then to consider alternatives, they do not renounce the paradigm that has led them into crisis. They do not, that is, treat anomalies as counterinstances, though in the vocabulary of philosophy of science that is what they are.

However, this state of disagreement is not perpetual because, as Kuhn concedes above, an accumulation of anomalies forces a crisis in the scientific community. During a period of crisis, the paradigm reigns, yes, but is also now and then challenged by alternately conceived paradigms that

  1. Are sufficiently unprecedented
  2. Are open-ended to provide opportunities for growth
  3. Are able to explain those anomalies that threatens the reign of the extant paradigm

The new paradigm imposes a new framework of ideals to contain the same knowledge that dethroned the old paradigm, and because of a new framework, new relations between different bits of information become possible. Therefore, paradigm shifts are periods encompassing rejection and re-adoption as well as restructuring and discovery.

Kuhn ties together here three postulates: incommensurability, scientific communication, and knowledge being non-accumulative. When a new paradigm takes over, there is often a reshuffling of subjects – some are relegated to a different department, some departments are broadened to include more subjects than were there previously, while other subjects are confined to illogicality.

During this phase, some areas of knowledge may no longer be measured with the same standards that have gone before them.

Because of this incommensurability, scientific communication within their community breaks down, but only for the period of the crisis. For one, because of the new framework, some scientific terms change their meaning, and because multiple revolutions have happened in the past, Kuhn assumes the liberty here to conclude that scientific knowledge is non-accumulative. This facet of evolution was first considered by Herbert Butterfield in his The Origins of Modern Science, 1300-1800. Kuhn, in his work, then drew a comparison to visual gestalt (p. 85).

The Gestalt principles of visual perception seek to explain why the human mind sees two faces before it can identify the vase in the picture.

Just as in politics, when during a time of instability the people turn to conservative ideals to recreate a state of calm, scientists get back to a debate over the fundamentals of science to choose a successor paradigm. This is a gradual process, Kuhn says, that may or may not yield a new paradigm that is completely successful in explaining all the anomalies.

The discovery of QCs

On April 8, 1982, Dan Shechtman, a crystallographer working at the U. S. National Bureau of Standards (NBS), made a discovery that would nothing less than shatter the centuries-old assumptions of physical chemistry. Studying the molecular structure of an alloy of aluminium and manganese using electron diffraction, Shechtman noted an impossible arrangement of the molecules.

In electron diffraction, electrons are used to study extremely small objects, such as atoms and molecules, because the wavelength of electrons – which determines the resolution of the image produced – can be controlled by their electric charge. Photons lack this charge and are therefore unsuitable for high-precision observation at the atomic level.

When accelerated electrons strike the object under study, their wave nature takes over and they form an interference pattern on the observer lens when they are scattered. The device then works backward to reproduce the surface that may have generated the recorded pattern, in the process yielding an image of the surface. On that day in April, this is what Shechtman saw (note: the brightness of each node is only an indication of how far it is from the observer lens).

The electron-diffraction pattern exposing a quasicrystal’s lattice structure (Image from Ars Technica)

The diffraction pattern shows the molecules arranged in repeating pentagonal rings. That meant that the crystal exhibited 5-fold symmetry, i.e. an arrangement that was symmetrical about five axes. At the time, molecular arrangements were restricted by the then-36-year old crystallographic restriction theorem, which held that arrangements with only 2-, 3-, 4- and 6-fold symmetries were allowed. In fact, Shechtman had passed his university exams proving that 5-fold symmetries couldn’t exist!

At the time of discovery, Shechtman couldn’t believe his eyes because it was an anomaly. In keeping with tradition, in fact, he proceeded to look for experimental errors. Only after he could find none did he begin to consider reporting the discovery.

A photograph showing the pages from Shechtman’s logbook from the day he made the seemingly anomalous observation. Observe the words “10 Fold???”

In the second half of the 20th century, the field of crystallography was beginning to see some remarkable discoveries, but none of them as unprecedented as that of QCs would turn out to be. This was because of the development of spectroscopy, a subject that studied the interaction of matter and radiation.

Using devices such as X-ray spectrometers and tunneling electron microscopes (TEM), scientists could literally look at a molecule instead of having to determine its form via chemical reactions. In such a period, there was tremendous growth in physical chemistry because of the imaginative mind of one man who would later be called one of the greatest chemists of all time as well as make life difficult for Shechtman: Linus Carl Pauling.

Pauling epitomized the aspect of Kuhn’s philosophy that refused to let an old paradigm die, and therefore posed a significant hindrance to Shechtman’s radical new idea. While Shechtman attempted to present his discovery of QCs as an anomaly that he thought prompted crisis, Pauling infamously declared, “There is no such thing as quasi-crystals, only quasi-scientists.

Media reportage

The clash between Pauling and Shechtman, rather the “old school” and the “new kid”, created some attrition within universities in the United States and Israel, who with Shechtman was affiliated. While a select group of individuals who were convinced of the veracity of the radical claims set about studying it further, others – perhaps under the weight of Pauling’s credibility – dismissed the work as erroneous and desperate. The most important entity classifiable under the latter was the Journal of Applied Physics, which refused to publish Shechtman’s finding.

In this turmoil, there was a collapse of communication between scientists of the two factions. Unfortunately, the media’s coverage of this incident was limited: a few articles appeared in the mid-1980s in newspapers, magazines and journals; in 1988 when Pauling published his own paper on QCs; in 1999 when Shechtman won the prestigious Wolf Prize in mathematics; and in 2011, when he won the Nobel Prize in chemistry.

Despite the low coverage, the media managed to make known the existence of such things as QCs to a wider community as well as to a less-sophisticated one. The rift between Pauling and Shechtman was notable because, apart from reflecting Kuhn’s views, it also brought to light the mental block scientists professed when it came to falsification of their work, and how that prevented science as such from progressing rapidly. Anyway, such speculations are all based in the media’s representation of the events.