87504 - 2 - The Continental Drift Controversy : Volume I : Wegener and the Early Debate

The continental drift, or more generally the mobilism controversy lasted sixty years. It was the longest and most important controversy of the last century in Earth science, and one of the more important in all of science in that period. Within it were many sub-controversies and their important feature was that some were long-lived too, even surviving the controversy itself. For example, the apparent conflict noticed in the 1920s between the “Permian” glacial Squantum Tillite of the Boston region and the equatorial situation assigned to that part of North America by drift theory was not resolved until the beginning of the twenty-first century, when radiometric dating assigned it to the Late Precambrian glaciation (Snowball or Panglacial Earth) (Thompson and Bowring, 2000). Also outliving the controversy and of much more general significance was the debate about the mechanism of continental drift, which began in the early 1920s and, although much progress has been made, is still not entirely resolved ninety years later. Throughout much of the controversy a solution to the mechanism question was regarded by most workers as essential, but at the end it was jettisoned and left in the wake of plate tectonics. Not only was it left unresolved by plate tectonics, it had to be first set aside in order for progress to be made – set aside as a problem for the future. In the end, the avalanche of evidence for the geometrification of tectonics and the convincing kinematic picture it gave overwhelmed concerns about dynamics – the mechanism difficulty, as I shall call it. The durability of the sub-controversies lends a certain repetitiveness to the history of the controversy. Repeatedly problems were thought to have been laid to rest and then revived and discussed all over again and so on, and this is why, in the narrative, they and the scientists involved appear and reappear time and time again. These are not inadvertent repetitions (although I am sure there are some of those too), they are a characteristic feature of the story – how it unfolds. In these three volumes, scientists and their work are introduced in rough chronological order beginning in Chapter 2. In this first chapter I comment on what I believe is a remarkable similarity in the arguments used throughout the controversy. This common thread provides a degree