Se Lyell está sendo questionado, e Darwin se inspirou nele, então...

sábado, julho 26, 2008

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Darwin reconheceu no Origin of Species a grande contribuição que Lyell deu para suas idéias, e que até o seu livro poderia ter sido escrito por ele. No livro Worlds Before Adam: The Reconstruction of Geohistory in the Age of Reform, Martin J. S. Rudwick questiona as idéias de Lyell sobre geologia. Ora, se a contribuição de Lyell para a geologia está sendo questionada, e vez que Darwin se inspirou nele para dar uma base diferente para a biologia, atenção historiadores e filósofos da ciência, QED — Darwin também está sendo questionado.


Books and Arts
Nature 454, 406-407 (24 July 2008) | doi:10.1038/454406b; Published online 23 July 2008
Geological history turned upside down

Victor R. Baker

BOOK REVIEWED-Worlds Before Adam: The Reconstruction of Geohistory in the Age of Reform

by Martin J. S. Rudwick

University of Chicago Press: 2008. 614 pp. $49.00

Geologists study Earth by applying principles borrowed from more fundamental sciences. Yet geology also has its own set of attitudes that have accrued during the discipline's long history. The nature of geological inquiry, involving a synthesis of historical and philosophical reasoning, lies at the heart of Martin Rudwick's fine new book.

Worlds Before Adam shows that the emergence of modern geology was comparable in its cultural impact with that of relativity or Darwinian evolution. Rudwick, an influential historian of Earth science, emphasizes geology's historical and causal approaches to understanding, complementing his magisterial book Bursting the Limits of Time (University of Chicago Press, 2005). This earlier work covered the period between 1787 and 1822, when French savant Georges Cuvier and his fellow continental geologists gave meaning to signs of the past, such as fossils and strata, in the same way as historians and archaeologists use monuments and archives to map human history. Worlds Before Adam looks at how the ideas generated by Cuvier and others came together with more theoretical concepts between 1820 and 1845.

Rudwick's books are myth-busters, of which writers of introductory geology texts and popularizations should take note. In both volumes he counters the Anglocentric view that James Hutton, William Smith and Charles Lyell were the founders of modern geology who shone their British intellectual light onto the darkness of continental musings. To a large degree, he argues, the reverse was the case.

Controversially, Rudwick challenges the view that geology's development is a story of secular progress. He shows that the founders of geology were almost all men of faith. Yet they often engaged in fierce debates with pseudo-scientists who ascribed absolute authority to readings of the Bible. Theologians have discredited such views for centuries, but they still persist, with geologists continuing to refute them.

If contemporary lists of the greatest scientists feature a geologist at all, it is usually Lyell, a central figure in Worlds Before Adam. Lyell intended the title of his great multi-volume opus Principles of Geology (first published in 1830–1833) to recall Isaac Newton's Principia. He sought to recast geology on firm foundations, just as Newton had done for physics. Following his geologist contemporaries and predecessors, Lyell used the understanding of present-day causes to interpret the deep past — a principle termed actualism. Rudwick explains that Lyell's excellent descriptions of current geological processes, embellished with observations from his own geological excursions, derived from an original listing by the eighteenth-century German scholar Karl Ernst Adolf von Hoff. Lyell greatly extended the actualistic method by making pronouncements about how the complex geological processes of the past occurred through the progressive action of small-scale procedures that were still in operation, and by prescribing how geologists should reason about these past processes.

Rudwick shows that Lyell's ideas met with almost universal criticism. This was not caused by his advocacy of actualism, which was widely used, nor was any serious denunciation forthcoming from the biblical literalists, who were considered anti-scientific by Lyell and by his critics. Instead, the geological facts themselves seemed contrary to Lyell's vision of uniform action by small-scale processes operating over a long time. Examples include evidence for sudden mass extinctions from records in various 'bone caves', the existence of huge blocks sitting erratically out of geological place in the Alps and northern Europe, and deep U-shaped valleys containing streams too small to account for their excavation. Lyell's critics held that one should inquire into nature through evidence, rather than through privileged reasoning.

The great Cambridge polymath William Whewell named the two sides in the debate. Lyell's advocates he labelled 'uniformitarians'; their opponents he called 'catastrophists'. It is an irony of subsequent developments in geology, and a testimony to the success of Lyell's advocacy, that catastrophism came to be regarded as unconventional. This perverted Whewell's original intention, which was to show that the uniformitarians and Lyell were extreme in thinking that geologists should say in advance how nature works, through slow and uniform processes, before interpreting the evidence.

Worlds Before Adam concludes with the development of glacial theory, popularized in the nineteenth century by Cuvier's disciple Louis Agassiz, perhaps the greatest of the catastrophists. Agassiz's theory of the great spread of ice sheets during relatively recent geological time gained rapid acceptance among catastrophists because it accounted for many anomalous features originally ascribed to huge floods or tsunamis. However, Lyell resisted, remaining true to his epistemological project.

As we enter an era of global crises about water, energy and the environment, and as we seek to understand the development of our species among others in one corner of the Universe, geologists' perspectives give a means for both understanding and coping. In showing how these perspectives arose, Rudwick highlights an underappreciated, glorious advance in human thought, the documentation of which is a rather glorious achievement in itself.