These generalizations are also based primarily on a sample of 'classic', pre-twentieth century discoveries, although we have made occasional references to more recent discoveries. The kind of intense negotiations that went on in the Devonian case also characterized the discovery of the double-helix structure of DNA, though the pattern of negotiations was different. Our Murchison and Sedgwick in the DNA case are Watson and Crick, but whereas the former were gentlemen of science, Watson was a post-doc and Crick a Ph.D. student at the Cavendish laboratory. Furthermore, whereas Murchison and Sedgwick eventually took credit for discovering separate systems, Watson and Crick shared the credit for DNA. Still, both discoveries emphasize the importance of collaborative teams.
Watson and Crick took Linus Pauling's methods for finding the helical structure in a complex protein and applied them to the structure of DNA. Initially, they came up with a triple helical structure, but Maurice Wilkins and Rosalind Franklin quickly convinced them that this model was incorrect. Here Wilkins and Franklin played roles similar to figures like De la Beche and Austen in the great Devonian. Franklin, in particular, supplied a critical photograph that suggested the double-helical structure, and also important constraints the model had to satisfy. While Watson and Crick received the credit, one could argue that Franklin, Wilkins and others in the small scientific community focusing on this problem deserve some of the credit, just as the small community of geologists played a major role in discovering the Devonian period.
A quick skate through the list of four generalizations suggest that they could be applied to the discovery of the double helix, though we should remember that the primary source is the recollections of one of the discoverers and such recollections are not totally reliable (Ericsson & Simon, 1984).
1. Watson and Crick targeted a problem that was recognized as very important.
2. They transformed it into a form that suggested the path to solution and found or were given the appropriate data. According to Weisberg, the most significant problem transformation was the first one, suggested by Pauling: "There were thus several discontinuities in Watson and Crick's discovery: the change from three to two strands, the change in position of the backbones, and the change from parallel to antiparallel backbone chains. All of these discontinuities came about without restructuring; both alternatives existed as possibilities throughout the work because Watson and Crick had decided DNA was helical" (Weisberg, 1995, p. 60). However, if the other transformations or re-structurings were so trivial, one might ask why other researchers like Franklin, Pauling and Wilkins did not solve the problem. Watson and Crick had to do a great deal of physical modeling in an effort to find the correct sequence and structure, literally building the DNA sequence out of cardboard. This kind of modeling was favored by Pauling, but was anathema to Wilkins and Franklin.
The amount of transformation necessary to discovery varies from case to case. Consider an astronomical example: the location of the optical source of a pulsar. The transformation here was to recognize that the optical pulses recorded on an oscilloscope corresponded to a radio pulsar in the Crab Nebula. This is actually a significant transformation that would not be obvious to someone outside this area of astronomy, but was not a significant transformation for the astronomers involved. It was not a s trivial as a Baconian data-driven discovery, either--they had to check and re-check for artifacts and alternate explanations (Lynch, 1992).
3. Watson and Crick were both flexible and stubborn, sticking to their helical mental model but modifying the shape and arrangement of the structure as they found or were given new data.
4. It is not clear that writing played a major role in this discovery. Watson did jot down important ideas from time to time, though he did not keep a notebook. His breezy account of the discovery should be supplemented by a careful study of any written documents, including drafts of the research note announcing the discovery.
Communication, however, was extremely important. Watson and Crick were not only in constant conversation with each other, they were also in touch with Wilkins, Franklin and, through his son, with Pauling. They drew on the expertise of other scientists and laboratories as well. For example, Watson admitted that one of their greatest advantages was having the crystallographer Jerry Donohue in the office next door; it was Jerry who told Watson that information commonly available in chemical textbooks about guanine and thymine was wrong. This news eliminated the possibility that DNA was built on a 'like pairs with like' model; instead, adenine paired with thymine and guanine with cytosine.
Perhaps it would be better to broaden the generalization about writing to focus on communication, and keep writing as an important category:
5. Communication is part of discovery.
Important forms of communication include: A. Writing 1. Journal articles 2. Letters 3. Notebooks and rough sketches of ideas on scraps of paper B. Oral communication 1. Conference papers 2. Conversations
So, at least one twentieth century case-study has reinforced the relevance of the generalizations and helped us modify them. More and more excellent studies of twentieth century scientists are emerging; I encourage readers to try these generalizations on other cases. For example, Holton describes in elegant detail the way in which Einstein and Bohr transformed problems (Holton, 1973) and Galison takes us into the fine-grained negotiations involved in experimental physics (Galison, 1987).
The larger question is, can one make generalizations about discovery at all, or is each act of discovery entirely idiosyncratic? The problem with many studies of discovery is that they are framed in the language of the author, making comparisons difficult. Holton, Galison and Gruber use different frameworks and focus on different aspects of discovery. This is creative and may lead to a broader view of the phenomenon, but it makes comparison difficult.
In this chapter, I tried to pick discovery cases which were detailed and comprehensible enough to allow a reader to question the perspectives taken by those who studied them. The fact that each had inspired some kind of computational simulation gave us a basis for comparison. I cast these discoveries in my own framework, which I will discuss in more detail in the next chapter--in part so the reader will see my assumptions, and feel free to disagree with them.
What about failed discoveries? All of the above generalizations might characterize failures as well as successes. For example, Leverrier, who predicted the existence and position of Neptune, used the same techniques to predict the existence of a planet Vulcan between Mercury and the sun (Schaffer, 1994). Another astronomical case will provide us with a more detailed case of a discovery that wasn't.
This page was last edited: Wednesday, July 14, 1999