Overcoming underdetermination

Guest blogger Caitlin Wylie writes...

In a dusty laboratory, behind the scenes of an American museum, a volunteer fossil preparator used a delicate pen-sized jackhammer to carefully chip rock off a dinosaur bone. As a participant observer in the lab, I was looking over his shoulder. When the volunteer asked a nearby staff preparator what species the fossil belonged to, she answered that one paleontologist had said the specimen is an Eolambia. Another paleontologist, overhearing, added, “Supposedly”, because he hadn’t seen any evidence for that species classification.

 “Oooh, I’m in a controversy!” the volunteer joked. “One little slip [with my jackhammer] and it won’t be Eolambia.”

“It’ll be neo-lambia!” the paleontologist quipped.

Everyone in the lab laughed at this silly idea that a preparator could alter a fossil to the extent that scientists would designate it as a new – “neo” – species. But is it so silly?

This joke refers to the widely acknowledged underdetermination of species categories by evidence. Organisms can be organized into multiple possible species and there is never sufficient information to allow a universal or predetermined categorization. Riotous debates about species classification (e.g., splitting vs. lumping and especially about our own ancestors, Adrian Currie’s paper on Triceratops’ “mother”) are evidence for the non-obvious distinctions between species, a situation further complicated by the variety of definitions of “species”. Fossils, as notoriously incomplete, rare, and often mangled by geological processes, are already less-than-ideal representatives of organisms. Fossils thus allow for – and perhaps even require – the consideration of diverse possible interpretations. 

But this joke also highlights what we might think of as the underdetermination of specimens by the surrounding material, in that deciding what is fossil (i.e., valuable data) and what is rock (i.e., junk that’s obscuring the data) is rarely obvious. Figure 1, for example, shows a fossil deemed “ugly” by preparators because its rock and bone look so similar.

Figure 1: Bones from a fossil marine reptile, partially prepared (author's photo)

Figure 1: Bones from a fossil marine reptile, partially prepared (author's photo)

A fossil’s shape is therefore a result of the preparator’s visual judgment to identify specimen from rock and manual skill to remove (only and all) the obscuring rock (Wylie, 2012). This seems not so different from sculpture (Rieppel, 2012), as even preparators admit, though they assert that the two are different (Wylie, 2015). Specimen underdetermination is a potentially more troubling problem for fossil researchers than species underdetermination, because specimens are of course the basis for defining species.

The non-obvious, debatable, underdetermined shape of fossil specimens is especially evident with trace fossils, such as impressions or natural casts of skin, feathers, footprints, burrows, etc. These traces are preserved in the surrounding rock and are not actually fossilized, thus further complicating the distinction between fossil and not-fossil. Some preparators and scientists told me that they suspect one reason why trace fossils are so rare is because preparators are focused on the bones, not on patterns in the surrounding rock. Of course, preparators focus on the bones because scientists are typically most interested in the bones. As a result of this bias towards bones, preparators may define trace fossils as “rock” and remove them to reveal the bones. If true, this would be an example of the high-impact and irreversible implications of the decisions of defining specimen vs. not-specimen. Peter Galison describes the process of distinguishing data from noise as inseparable:  “The task of removing the background is not ancillary to identifying the foreground – the two tasks are one and the same” (1987, p. 256, his emphasis). Thus identifying the rock defines the fossil, and vice versa.

This joke also asserts the power of preparators. Perhaps the lab workers laughed at the idea of a preparator-invented “neolambia” not because it was silly, but because it was possible. So how do paleontologists overcome the potential accusation that they’re studying the products of technicians rather than of nature? Other scientists address this problem by using standard protocols to prepare their data and describing them in a “Methods” section in publications. Paleontologists, in comparison, rely on informally-trained technicians who use and invent a variety of nonstandard methods, which are rarely mentioned in print. Paleontologists talk about preparation as a separate process from research, a perception that functions – perhaps unintentionally – as a reason for omitting preparation from research papers. Steven Shapin argues that “the invisible technician” is only made visible – i.e., mentioned in lab reports – when something goes wrong, and then the technician is blamed as the culprit (1989, p. 558; 1994, pp. 389-91). But accusations of preparators’ poor work are rare. Effects of preparation – good and bad – tend to be as invisible in print as preparators are.

One unusual case of preparators forced into the limelight of scientific controversy illuminates the invisible and potentially questionable work of specimen-making. In 1985, two respected astrobiologists, Fred Hoyle and Chandra Wickramasinghe, claimed that the famous Archaeopteryx lithographica specimen in London was a forgery (e.g., 1986; Watkins et al., 1985a, 1985b).

Figure 2: Archaeopteryx specimen (not the London specimen) (photo credit: H. Raab).

Figure 2: Archaeopteryx specimen (not the London specimen) (photo credit: H. Raab).

They pointed to several alterations made to the specimen at various times in its long history as evidence of its constructedness. The most recent example concerned the specimen’s partial skull:  

In 1862 the ‘brain-case’ was said to be that of a bird… As time went on, and in the opinion of paleontologists the skeleton became ever less bird-like, the thought of the brain case being like a magpie must have seemed unattractive… So what to do? Simply remove the brain case, as was done a year or two ago. (Hoyle and Wickramasinghe, 1986, p. 97)

The authors describe this removal as “a whole chunk of the main slab now hacked away”, in “a vigorous assault that was mounted on this unfortunate creature, with extensive chisel marks to be seen” (1986, p. 99). Peter Whybrow, who was the head of the paleontology laboratory at the British Museum (Natural History)(now named the Natural History Museum), had described his work of separating the brain case from the specimen’s main slab as done meticulously and without damage, in a rare publication about preparation methods (Whybrow, 1982). But Hoyle and Wickramasinghe rejected that paper:  “How it was possible to write of not causing the slightest damage to the fossil in the wake of the gross defacement… we leave to the reader’s judgement” (1986, p. 99). (For more fun beliefs held by these authors, see here).

In response to this claim of a fraudulent Archaeopteryx, several of the museum’s paleontologists and Whybrow published a powerful rebuttal article in Science. They systematically documented the impossibility of Hoyle and Wickramasinghe’s many accusations by thin-sectioning the slab and matching subtle cracks and dendrites throughout to show that the slab has no irregularities and is therefore authentic (Charig et al., 1986). They highlight the strength of their arguments while demeaning the forgery claim by describing their paper as “using a sledgehammer to crack a rather trivial nut”, but they cite Hoyle’s fame and the threat of creationists as crucial reasons to “put the record straight” (1986, p. 623). They do not, however, mention Archaeopteryx’s brain case, perhaps because geology cannot show that the bone had been removed in good faith. Because of this omission, maybe, or because he was so offended by the accusation of being a forger, Whybrow further defended his preparation work in a letter to New Scientist. In it, Whybrow explained that he was not concerned about wrongful interpretations:  “I do not really care if Hoyle and Wickramasinghe believe Archaeopteryx to be a forgery. They can hold sincere views, however mistaken” (1986, p. 62). Instead, he was angry that they had questioned the legitimacy of his preparation methods and his professional credibility, because they “reject… the authenticity of the London Archaeopteryx by stating that devious, deceitful and unprofessional methods have been recently used” (1986, p. 62).

Here we see exposed for a moment the soft underbelly of rock-based science. Interpreting the fossil is not Whybrow’s concern; its honest and skillful preparation is. Debates over knowledge claims don’t worry him – they’re normal, after all – but debates about the quality and truthfulness of his work are unacceptable. Scientists recognize the underdetermination of knowledge by data:  they know that multiple interpretations of data are possible, and that, as a result, their interpretations must be defended and will most likely be debated. But reminding them that specimens themselves are underdetermined by raw material – e.g., that specimens may take different forms and yield different data depending on how they are processed – is more dangerous, because it threatens the natural objects that are the foundation of empirical research.

In no way am I saying that scientists and technicians are wrong, or “deceitful”, or “unprofessional”, as Whybrow felt accused of. Underdetermination is not specific to fossils or species; it is an underlying fixture of scientific knowledge. The fascinating thing is how science practitioners develop ways to make knowledge from always-incomplete information. For example, they have developed experience-based know-how for judging data vs. not-data, skillful ways of separating the two (e.g., fossil preparation, “cleaning” experimental data by discarding failed trials, algorithms that select relevant data), trust in each other’s work, and divisions of visible and invisible labor. By obscuring the work of making specimens researchable and by defending preparators’ skill and integrity in rare cases of blame, both researchers and preparators protect fossils’ status as natural objects, or at least as natural enough to be the basis of our knowledge about evolution and Earth history.

With thanks to Matthew A. Brown, Jonathan Birch, Emily McTernan, and the many fossil preparators who have welcomed me into their labs and their lives


Caitlin Wylie is an assistant professor in the Program in Science, Technology and Society at the University of Virginia. She prepared fossils as an undergrad at the University of Chicago and as a volunteer at London’s Natural History Museum. Preparators’ socially and technically fascinating work inspired her ethnographic research about why and how preparators are powerful decision-makers and data-producers in fossil laboratories, yet missing from research publications. Caitlin is writing a book about preparators, lab practices, and the construction of specimens and knowledge.


Charig, A. J., Greenaway, F., Milner, A. C., Walker, C. A., & Whybrow, P. J. (1986). Archaeopteryx is not a forgery. Science, 232, 622–6.

Galison, P. (1987). How experiments end. Chicago: University of Chicago Press.

Hoyle, F., & Wickramasinghe, C. (1986). Archaeopteryx, the primordial bird: a case of fossil forgery. Swansea: Christopher Davies Publishers.

Rieppel, L. (2012). Bringing dinosaurs back to life: exhibiting prehistory at the American Museum of Natural History. Isis, 103(3), 460–90.

Shapin, S. (1989). The invisible technician. American Scientist, 77(6), 554–563.

Shapin, S. (1994). A social history of truth: civility and science in seventeenth-century England. Chicago: University of Chicago Press.

Watkins, R., Hoyle, F., Wickramasinghe, C., Watkins, J., Rabilizirov, R., & Spetner, L. (1985). Archaeopteryx - a further comment. The British Journal of Photography, 132(6504), 358–9.

Watkins, R., Hoyle, F., Wickramasinghe, C., Watkins, J., Rabilizirov, R., & Spetner, L. (1985). Archaeopteryx: a photographic study. The British Journal of Photography, 132(6501), 264–6.

Whybrow, P. J. (1982). Preparation of the cranium of the holotype of Archaeopteryx lithographica from the collections of the British Museum (Natural History). Neues Jahrbuch Fur Geologie Und Palaontologie, 3, 184–192.

Whybrow, P. J. (1986). Rare controversy. New Scientist, 4 September, 62.

Wylie, C. D. (2015). “The artist’s piece is already in the stone”: constructing creativity in paleontology laboratories. Social Studies of Science, 45(1), 31–55.

Wylie, C. D. (2013). Invisible technicians: a sociology of scientific work, workers, and specimens in paleontology laboratories (Unpublished doctoral dissertation). University of Cambridge, Cambridge, UK.