Most undergraduate-level geoscience texts offer a paltry introduction to the nuanced approach to hypothesis testing that geoscientists use when conducting research and writing proposals. Fortunately, there are a handful of excellent papers that are accessible to geoscience undergraduates. Two historical papers by the eminent American geologists G. K. Gilbert and T. C. Chamberlin (Gilbert, 1886; Chamberlin, 1897) were the first to fully articulate and explore the method of multiple working hypotheses. Both papers still make for inspirational reading. A long essay on the scientific method by Johnson (1933) presents both a recipe for rigorous scientific thinking and a traditional but detailed articulation of linear hypothesis testing using geologic examples. More recently, papers by Frodeman (1995) about the fundamentally non-linear nature of interpretation and reasoning in the geosciences and Cleland (2001) about a "smoking gun" approach to validating hypotheses are helpful articulations of the geoscientific method, i.e. a shared understanding of how geoscientists articulate, frame, and tackle research questions.
What first-year undergraduates know about scientific methodology likely comes from a high school science class in which they learned a linear scientific method: identify a problem, make a hypothesis, gather data, and test the hypothesis. Yet geologists commonly follow a nonlinear path towards testing hypotheses, and we tend to work on many hypotheses at a time, rarely fully accepting or rejecting any of them. For undergraduate geology majors (and even graduate students), learning the nuances of testing hypotheses like a practicing geologist is a transition, and few college-level geology textbooks adequately support that transition. For example, the textbook I use to teach Physical Geology, Marshak's Essentials of Earth, articulates a linear version of the scientific method. By way of more detailed explanation, Essentials of Earth carefully distinguishes between a hypothesis and a theory, using as a case study the development of plate tectonic theory from the hypothesis of continental drift. Comparable descriptions of the nature of hypothesis testing, the distinction between a hypothesis and a theory, and the case study of the history of ideas about drift and tectonics occur early in both Monroe, Wicander, and Hazlett's Physical Geology and Chernikoff and Whitney's Geology.
It seems natural for introductory geology textbooks to use plate tectonic theory to illustrate elements of the scientific method. I joke with my Physical Geology class that the story of the plate tectonic revolution is the American geologist's Passover story; we delight in its telling and retelling. The story offers opportunities to elaborate upon any number of subdisciplines in geology, from paleontology to rock magnetism. Wegener makes for a wonderful hero - dead in the field before his time. And the embrace of plate tectonics in America is certainly an excellent case study of the development of a theory: plate tectonics only gained widespread embrace after support developed within many different subdisciplines; it was a hypothesis that has now survived repeated challenges; and it has predictive power. Perhaps introductory geology textbooks focus on this careful explanation of the scientific usage of the word theory because of the ongoing culture wars over evolution (which is, after all, "only a theory"). We hope that our undergraduates become scientifically literate, and literacy involves a clear understanding of what a scientific theory is.
Yet we also hope that our undergraduate geoscience majors become more than literate. We hope that they become skilled researchers and sophisticated thinkers. Specifically, we want them to learn a nuanced and realistic approach to designing hypotheses and developing tests for them. I have found surprisingly little support for this learning in college-level geoscience textbooks. …