Understanding the history of the earth before the discovery of tectonics
While reading S.J. Gould’s “Time’s arrow, time’s cycle – Myth and metaphore in the Discovery of Geological Time“, I noticed a few things.
In the first part of the book, Gould describes the ideas on the -brief- history of the earth as seen by Thomas Burnett (late 17th century). It gets far more interesting, as far as the modern thought is concerned, in the second part of the book. There, we find the work of James Hutton, a scottish geologist of the 18th century. He had made very accurate and original observations in his homeland (discordances, discontinuities…). He tried to explain them but in vain. How would it be possible to understand a discontinuity, sediment orientation, etc. without having any knowledge of a mechanism that would allow change of the surface of the earth? How is it possible to study and understand the history of the earth without using tectonics?
The third part of the book is dedicated to the work of Charles Lyell (19th century). There again, we see that he observes faults and other landscape results of earthquakes. As much as Lyell’s work is significant to Geology, the mechanism responsible for some of his observations was still unknown; raising the same problems of the changes of the surface of the earth. All the theories preceding the discovery of tectonics were speculative even if the scientists tried to be realistic.
If we want to do a parallel with evolutionary biology, I remember the famous quote of Theodosius Dobzhansky: “Nothing makes sense in Biology except in the light of Evolution”. Well, I think that something similar can be said about tectonics: “Nothing makes sense in Geology, except in the light of Tectonics”. Therefore, Tectonics is to Geology what Evolution is to Biology.