GEOLOGICAL HYPOTHESES: MULTIPLE, WORKING, AND OUTRAGEOUS

Charles S. Peirce (1839-1914), originator of the American philosophical movement known as “pragmatism,” considered geology to be, “…the most difficult of the sciences, barring none.” In 1878 Peirce classified the physical sciences by their methodologies, as opposed to their subject matter. Physics he classified as the science of deduction, in that it makes maximal use of mathematics, which is “the science that draws necessary conclusions” from truths that must already be presumed to be present in the premises. Much of chemistry and biology he classified as sciences of induction. Geology, Peirce observed in 1878, is the science of hypothesis, and Peirce’s writings on this subject are particularly relevant to the philosophy of geology (von Engelhard and Zimmermann, 1988, Theory of Earth Science). Somewhat later, methods for hypothetical reasoning in geology were described in papers by Grove Karl Gilbert (1843-1918) on “The Inculcation of Scientific Method by Example” (1886) and “The Origin of Hypotheses” (1896), and by Thomas Chrowder Chamberlin (1843-1928) on “The Method of Multiple Working Hypotheses” (1890) and “The Methods of the Earth-Sciences” (1904). William Morris Davis (1850-1934) added important insights to the role of hypotheses in geology in his paper “The Value of Outrageous Geological Hypotheses” (1926). All these papers hold that geological hypotheses derive from experience with nature itself rather than from theoretical constructs about nature. They include pragmatic notions of anti-foundationalism, falsification, fallibilism, and critical common-sensism, as well as fruitfulness (ubrity) and open-mindedness of inquiry. Davis’s paper on “outrageous geological hypotheses” strongly advocated the latter, even suggesting (against the view at the time) that serious contemplation be given even to, “…the Wegener outrage of wandering continents.” For, following what Charles Peirce termed “The First Rule of Reason,” from a mere, “…off-hand verdict of ‘impossible or absurd’…” one learns absolutely nothing. Rather, reasoning requires “…a contemplation deliberate enough to seek out what conditions would make the outrage seem permissible and reasonable.” By following this latter formula in regard to the “Wegener outrage” geology produced its greatest scientific discoveries of the modern era.