In a subsequent argument (2023), Stern depends on one other auxiliary assumption associated to “preservation bias.” He argues that if a given interval in Earth’s historical past is bookended by two intervals of sufficient preservation, then we are able to assume that the intervening interval additionally adequately preserved proof. Any absence of proof within the intervening interval between intervals of sufficient preservation is thus a real absence. Along with clear proof for the operation of plate tectonics through the Neoproterozoic, Stern amends his earlier place and argues that there’s additionally clear proof for plate tectonics through the earlier Orosirian interval (through the Paleoproterozoic). As a result of proof is satisfactorily preserved for the Neoproterozoic and the Orosirian, Stern assumes that proof also needs to be adequately preserved through the interim. Nevertheless, we lack proof for plate tectonics through the meantime. Thus, Stern concludes that the Earth has skilled a number of episodes of plate tectonics, punctuated by a “boring” interval of little tectonic exercise within the interim. Stern’s auxiliary assumption about bookended preservation will seemingly be investigated by different geoscientists in response to his attraction to absence of proof.
Maybe some readers have already got noticed a possible objection to Stern’s assumptions. You may be pondering that he’s too uniformitarian in regards to the preservation of proof. As an example, many scientists have given various arguments to elucidate the shortage of preservation of rocks reminiscent of blueschist. Others have argued that the circumstances of the early Earth have been so totally different that plate tectonic processes didn’t kind blueschist (e.g., Palin and White 2015). Moreover, maybe a catastrophic occasion may destroy proof between two intervals of sufficient preservation. My fear is that with out within the first place interesting to absence of proof as proof of absence, such various explanations may by no means be pursued, leaving scientists disadvantaged of a richer understanding of their goal phenomena. For instance, on this case, scientists acquire insights into the metamorphic processes that kind blueschist by looking for to elucidate its absence. If the absence of blueschist weren’t thought of, then such insights may stay unknown.
* * *
In my forthcoming paper, I defend what I name a Pragmatic View of arguments from absence. The essential concept is that appeals to absence of proof as proof of absence are warranted within the paleosciences, as a result of they provide a theoretical scaffold to research auxiliary hypotheses. Auxiliary hypotheses are conditionals: “If H [our initial hypothesis] is true, then proof y can be noticed.” To check auxiliary hypotheses, scientists should entertain an preliminary speculation over different conceivable alternate options. Entertaining absence of proof as proof of absence permits Stern to contemplate auxiliary assumptions associated to the preservation of proof. Others have tried to refute him by specifying a wider vary of alternate options with their very own auxiliaries, towards which Stern’s speculation may be contrasted. Treating absence of proof as proof of absence gives the preliminary cause (in some instances, maybe the one cause) for investigating the implications of some hypotheses that may in any other case be uncared for. If geologists strictly adhered to the Probabilistic View, then Stern may by no means have supplied his arguments, and geologists could be disadvantaged of productive traces of inquiry which have arisen from his appeals.
Finally, I don’t want to dismiss the Probabilistic View. I merely want to level out that in lots of investigations, absence of proof guides scientists by focusing their investigations on attainable alternate options and auxiliaries which could clarify the absence. If scientists didn’t deal with absence of proof as proof of absence, then there could be comparatively little warrant for these investigations. But, these investigations permit scientists to make real progress in direction of extra refined fashions for the Earth’s deep previous.
The debates that preoccupy immediately’s paleogeologists are harking back to the debates that have been the main focus of the pioneers of glaciology within the late nineteenth century. In each contexts, a lot effort is devoted to explaining the absence of sure traces of hint proof. Doing so is just not a trivial matter: simply as plate tectonics is believed to destroy proof because it “recycles” the Earth’s crust, some glaciologists posited that transferring glaciers may destroy proof for previous episodes of submergence as they crawled throughout the land (Bell 1891). Glaciologists understood that absence of proof is proof of absence when discovering proof is very anticipated. Nonetheless, even when the likelihood of discovering proof is low or unclear, I believe that appeals to absence of proof as proof of absence have a spot in paleogeological pondering. Such appeals give rise to fruitful pursuits of attainable explanations for the absence in query.*
[* Matt will present his paper on the Pragmatic View at the meeting of the Philosophy of Science Association in November. He intends to develop an expanded version of the paper as a chapter in his dissertation. Plate tectonics is a complex, global phenomenon that has operated on Earth for millions (perhaps billions) of years, and geoscientific practices that make use of the theory are ripe for philosophical analysis. Stay tuned for more work on the “philosophy of plate tectonics!” And watch out for the next post on Extinct, which will continue the discussion of negative evidence in the historical sciences.]
Bell, D. 1891. Phenomena of the Glacial Epoch: II. The ‘Nice Submergence.’ Transactions of the Geological Society of Glasgow 9, no. 1: 100-38. https://doi.org/10.1144/transglas.9.1.100.
Bell, D. 1897. The ‘Nice Submergence’ Once more: Clava. Geological Journal 4, no. 1: 27-30. https://doi.org/10.1017/S001675680017503X.
Hamilton, W. B. 2011. Plate tectonics started in Neoproterozoic time, and plumes from deep mantle have by no means operated. Lithos 123, nos. 1-4: 1-20. https://doi.org/10.1016/j.lithos.2010.12.007.
Hopkins, M. T., Harrison, M. and Manning, E. C. 2008. Low warmth stream inferred from >4 Gyr zircons suggests Hadean plate boundary interactions. Nature 456: 493-96. https://doi.org/10.1038/nature07465.
Howorth, H. H. 1894. The North Sea Ice Sheet. Nature 50, no. 1282: 79. https://doi.org/10.1038/050079a0.
Jamieson, T. F. 1874. On the Final Stage of the Glacial Interval in North Britain. Quarterly Journal of the Geological Society of London 30, nos. 1-4: 317-38. https://doi.org/10.1144/GSL.JGS.1874.030.01-04.40.
Macnair, P., and Mort, F. eds. 1908. Historical past of the Geological Society of Glasgow, 1858-1908, with Biographical Notes of Distinguished Members. Glasgow: Geological Society of Glasgow.
NASA (1972). Challenge Cyclops: a Design Research of a System for Detecting Extraterrestrial Clever Life. https://ntrs.nasa.gov/citations/19730010095.
O’Toole, G. 2019. Absence of Proof Is Not Proof of Absence” Quote Investigator. https://quoteinvestigator.com/2019/09/17/absence/.
Palin, R. M., and White, R. W. 2015. Emergence of blueschists on Earth linked to secular modifications in oceanic crust composition. Nature Geoscience 9: 60-64. https://doi.org/10.1038/ngeo2605.
Palin, R. M., Santosh, M., Cao, W., Li, S., Hernández-Uribe, D. and Parsons, A. 2020. Secular change and the onset of plate tectonics on Earth. Earth-Science Opinions 207, 103172: 1-41. https://doi.org/10.1016/j.earscirev.2020.103172.
Sagan, C. and Druyan, A. 1995. The Demon-Haunted World: Science as a Candle within the Darkish. New York: Ballantine Books.
Schroder, J. 2023. The Exceptional Reverend Henry W. Crosskey, the Erratic Blocks Committee, and the Crosskey Assortment of Glacial Erratic Specimens. Birmingham Erratic Boulders Challenge. https://erraticsproject.org/henry_crosskey/.
Sheppard, T. 1895. On the Incidence of Scandinavian Boulders in England. The Glacialists’ Journal 3, no. 1: 129-32. https://babel.hathitrust.org/cgi/pt?id=uc1.b4182734&seq=149.
Smith, J. L. B. 1939. A Residing Fish of Mesozoic Sort. Nature 143: 455-56. https://doi.org/10.1038/143455a0.
Sober, E. 2009. Absence of proof and proof of absence: evidential transitivity in reference to fossils, fishing, fine-tuning, and firing squads. Philosophical Research 143: 63-90. https://doi.org/10.1007/s11098-008-9315-0.
Sollas, W. J. 1895. An Experiment to Illustrate the Mode of Circulation of a Viscous Fluid. Quarterly Journal of the Geological Society of London 51: 361-68. https://doi.org/10.1144/GSL.JGS.1895.051.01-04.28.
Stern, R. J. 2018. The evolution of plate tectonics. Philosophical Transactions of the Royal Society A 376, no. 20170406: 1-21. https://doi.org/10.1098/rsta.2017.0406.
Stern, R. J. 2023. The Orosirian (1800–2050 Ma) plate tectonic episode: Key for reconstructing the Proterozoic tectonic file. Geoscience Frontiers 14, no. 3: 101553. https://doi.org/10.1016/j.gsf.2023.101553.
Wallach, E. 2019. Inference from absence: the case of archaeology. Palgrave Communications 5, no. 94: 1-10. https://doi.org/10.1057/s41599-019-0307-9.