Predictive Networks and the Plate Tectonics Revolution

Alfred Wegener’s The Origin of Continents and Oceans was published in 1915. Therein, Wegener deviated from prevailing fixist expectations and argued for the relative displacement of continents across geological time. This hypothesis of continental mobilism languished for decades but rapidly became authoritative toward the end of the 1960s due to remarkable predictive successes of seafloor spreading and plate tectonics. In this work, I develop an account of the rapid ascendence of mobilism that is receptive to both the historical contingency and epistemic authority of scientific knowledge. I do this by developing an analytic framework for the assessment of knowledge claims, wherein predictive relationships within a set of commitments can provide epistemic insight into those commitments. I identify fundamental models of prediction testing. In the simplest cases, these models consist of pairs of commitments that either discord or concord with one another. Discordance falsifies a set of commitments and requires problem solving. Alternatively, concordance may provide epistemic support to commitments therein. Scientific knowledge may form predictive networks which consist of sets of partially overlapping concordances. These predictive networks facilitate the isolation of falsification and constrain problem solving. Additionally, the formation of certain kinds of network structures may provide epistemic support to commitments therein, when predictive successes are made particularly remarkable by their networked context. These snapping together events can unite previously independent lines of research and may result in the sudden recognition that a growing network is on the right track. I argue that alternative problem solving efforts undertaken by fixists and mobilists contributed to the formation of alternative predictive networks. By the 1960s, the accumulation of constraints during problem solving increasingly required grand modifications to fixist networks. Alternatively, a series of snapping together events – incorporating previously independent research in paleomagnetism, marine geology, and geochronology - supported mobilism in the second half of the 1960s. This resulted in the rapid ascendance of mobilism.