In 1877, Schiaparelli discovered canali (channels) on the surface of Mars. Earlier observers had hinted at the existence of such features, but Schiaparelli's were sharper and more systematically arranged (Hoyt, 1976). Percival Lowell, a wealthy American astronomer who built his own observatory, turned Schiaparelli's channels into canals, and became their champion in a debate that lasted over a quarter of a century. He came up with a complex system of canals, which he claimed were built by an advanced civilization as the planet turned gradually into a desert. Lowell and Schiaparelli were not the only ones to see these canals; indeed, members of the British Astronomical Association reported seeing more than a hundred.
If this were a successful discovery, there would have been the usual argument about who deserved priority, Lowell or Schiaparelli. Instead, the blame for a false discovery was laid at Lowell's door.
Three problems eroded support for the canals:
1) Not all astronomers saw them. Lowell argued that he used superior observational techniques, including spending far more hours observing Mars than most other astronomers.
2) Experimental evidence with human participants. Several astronomers attempted to conduct crude experiments to find out whether the canals might be some sort of optical allusion. One of Lowell's own observatory group placed artificial planets at a distance of about a mile, studied them through a telescope and found that "some well known planetary appearances could, in part, be regarded as very doubtful..." (Hoyt, 1976, p. 160). He was fired for his pains. A British astronomer, E. Walter Maunder, asked school boys to copy pictures of Mars; they drew in canals, even though none were present. A similar experiment with French schoolboys yielded the opposite result, but even so, the British Astronomical Association concluded that those members who had claimed to see canals "really saw something very different from the straight lines they imagined they were looking at" (Hoyt, 1976, p. 160).
3) Improved astronomical equipment: Eventually, better telescopes and photographic equipment found no evidence of the canals--the last reported sighting came in 1924. By this time, Lowell had been dead for eight years.
Do our generalizations show evidence of a failed discovery in the making, in this case?
Generalization #1: Were the canali on Mars a major problem before Lowell?
Arguably not--like many discoverers, Lowell sought to establish the significance of what he had found. For example, he might, like Schiaparelli, simply have said he had seen mysterious lines on the face of Mars. Instead, he developed a theory concerning the presence of the lines that explained why they varied with the seasons and why on at least one occasion, new ones appeared.
Generalization #2: Did Lowell transform the data?
Certainly--in hindsight, it is obvious he created the data, and convinced others that they saw it, too. But he would have argued he was simply describing what was there. In other words, for Lowell, this was a data-driven discovery--the lines came first, and the theory followed. Of all the discoveries we have studied so far, Lowell's had the weakest grounding in prior theory. However, Alfred Wegener's theory of continental drift began with an observation about the way the shapes of the continents and the continental shelves fit together (LeGrand, 1988). Unlike Lowell, Wegener was able to refer to multiple lines of evidence in favor of his discovery: not only did the shapes of the continents match, but also the flora and fauna on either side, and continental drift could be used to explain patterns of global climate change.
Generalization #3: Did he maintain a balance between stubbornness and flexibility?
No--once he had established his theory and network of canals, he never altered it in the face of criticism. This stubbornness is often a hallmark of successful scientists (Mitroff, 1974). Wegener, for example, never abandoned continental drift, though he altered what the he philosopher Imre Lakatos (Lakatos, 1978) refers to as the corollary assumptions surrounding the hard core of a theory. For example, in response to criticisms from physicists, Wegener de-emphasized the portions of his hypothesis that attempted to explain how the drift occurred (LeGrand, 1988).
Generalization #4: Did writing play a role in his discovery?
Lowell wrote extensively about the canals, particularly for a general audience, including books, lectures and articles for Scientific American and Nature. He also published regular, detailed reports from his observatory and wrote lengthy letters to his critics, especially those who challenged his priority. Lowell's writing made the canals controversy and Mars itself a center of attention shortly after the turn of the century. It is harder to say what role these writings played in convincing the author himself. More detailed study of Lowell's notebooks and drafts is needed.
The Lowell example suggests that our generalizations do not clearly discriminate between successful and unsuccessful discoverers. Lowell's work was based less on theory and he was a bit more stubborn than most of the other discoverers we have studied. Basically, Lowell's problem was that the canals just weren't there. This kind of appeal to reality as the ultimate arbiter of scientific disputes is anathema to some sociologists of science, whose work we will discuss briefly at the beginning of the next chapter. But in terms of advice for future discoveries, the Lowell case suggests another generalization, one that we hinted at in the Faraday case:
6. Successful discoverers often pursue a network of related enterprises.
This is necessary so that if one potential discovery doesn't pan out, it is not fatal to the whole enterprise (Gruber, 1989). As noted above, Faraday was never able to translate gravity into electricity, but this was not fatal to his larger goal of demonstrating the unity of forces--his failure in one area was balanced by significant successes in others. Similarly, Lowell's persistent search for a 'Planet X' beyond Neptune was instrumental in the eventual discovery of Pluto (Hoyt, 1980). He patiently calculated and re-calculated the probable orbit of 'Planet X', and put the Lowell observatory to work searching for it at intervals between 1905-1916, but he died before it could be discovered. Still, the search for Planet X was one of the legacies he left the observatory. Clyde Tombaugh, who was hired by the observatory and given new equipment to search for Planet X, found Pluto at a position close to Lowell's predictions in 1930.
But was the discovery due to Lowell's calculations or to sheer persistence? The controversy raged for years. Pluto appeared to be much smaller than Lowell's Planet X--so small that it was doubtful it could have had calculable effects on the orbit of Uranus. In 1978, the discovery of Pluto's moon Charon confirmed that Pluto was tiny--a few thousandths of the Earth's mass--and therefore it was persistence and not theory that discovered Pluto.
This discovery suggests a seventh, not entirely tongue-in-cheek generalization:
7. Successful discoverers have to be lucky.
One can be persistent, have a mental model which prepares one to make a discovery and the best possible equipment, but still fail because there simply isn't anything to be discovered. Of course, even a failed search can generate lots of important information. Tombaugh continued to search for planets beyond Pluto, and he was able to determine that none existed above the 16th magnitude. This kind of negative information is very important. In the course of this search, he also discovered a wide range of interesting astronomical phenomena, including a new globular cluster and a cloud of some 1800 galaxies (Hoyt, 1980).
Obviously, one cannot teach students to be lucky, but one can remind them to be prepared to take advantage of surprises. The bit of mold that landed in Alexander Fleming's petri dish is the classic example--had he and Florey, Chain and others not diligently pursued this bit of serendipity, penicillin never would have been created (Macfarlane, 1984).
Similarly, Henri Becquerel put uranium salts, a copper cross and a photographic plate in a dark closet, awaiting a sunny day to test his idea that sunlight would make the phosphorescent uranium emit rays. But after several cloudy days, Becquerel developed the plate anyway, and found to his surprise that the image of the cross stood out on the plate. It was the Curies, Ernest Rutherford and others who eventually explained the phenomenon of radioactivity. Marie Curie, in particular, received two Nobel Prizes, one shared with Becquerel and her husband Pierre for the discovery of radioactivity and another on her own for the discovery and isolation of radium. Despite these accomplishments, she was never admitted to the French Academy of Sciences, which was at that time an all-male club. Marie Curie eventually paid with her life for her pioneering work, but her daughter carried on, earning her own Nobel Prize for the discovery of artificial radioactivity, which she shared with her husband, Frederic Joliot (Quinn, 1995).
Were Fleming and Becquerel lucky? Yes, but as Pasteur noted, "in the field of observation chance favors only the prepared mind" (quoted in Root-Bernstein1989, p. 87). They were both primed to take advantage of a surprise generated in the course of their research. We should also refer to prepared minds, in both of these cases--others took the initial discoveries and carried them forward to make penicillin and radium.
So, instead of making 'be lucky' a sixth generalization, let us recognize the importance of taking advantage of luck. This fits under generalizations four and seven: great scientists pursue a network of related enterprises and remain open to surprises that occur in the course of their research program.
This page was last edited: Wednesday, July 14, 1999