Science in an Age of Reason - Kirkwood Community College



Expanding Geographical Knowledge,

the Earth’s History, & Meaning of Fossils

[Excerpts from The Norton History of the Environmental Sciences (1992)

by Peter J. Bowler]

[Eighteenth-century naturalists] began to explore the concept of a changing universe. Recognizing that the earth and its inhabitants have changed through time was certainly a major challenge to the traditional view of divine

creation . . . The drive to understand the forces that shape the world came into conflict with the desire to impose order upon it. The result was a complex mixture of theoretical systems that admitted some degree of change, but often tried to limit the impact of the new discoveries in ways that seem quite strange today . . .

Exploring the concept of a changing universe certainly had ideological implications. The concept of a static creation was taken to uphold traditional religious views, and hence the social hierarchy. Ideas based on predictable development encouraged the hope of steady reform. The radical materialists who postulated a chaotic world in which humankind played only a trivial role were striking at the roots of the existing social order . . .

At a less political level, it is clear that significant changes were at work in Europeans’ attitudes towards nature. The new science encouraged the view that the world was a purely material system that could be exploited for human gain . . . Governments financed the voyages of discovery and established mining colleges and other forms of technical education, presumably with a view to reaping commercial profit. Some scientists became government functionaries—but what effect did this have on their work? Was science still (as is often claimed) truly international, or did the rivalries of the European powers impose restrictions on what was done? . . .

The Earth Described

The eighteenth century saw a continuation of the voyages of discovery that were bringing Europe face to face with the rest of the world. Greatly improved mapping techniques were introduced. The search for better means of navigating a ship across trackless oceans was continued, and the problems largely solved. The Académie des Sciences of Paris undertook a programme of research designed to allow the determination of longitude by detailed observations of the moon, and by the late eighteenth century improved lunar tables had dramatically increased the accuracy of this technique. In 1714 the British government offered a prize of £20,000 for a method that would allow longitude to be determined to an accuracy of within half a degree. This prize would eventually be won by John Harrison in 1765 for a chronometer accurate enough to allow local time to be compared with time on the Greenwich meridian. At the same time, the French clockmaker Pierre Leroy improved the theoretical principles upon which chronometers were based. By the end of the century, Europeans could at last navigate their ships around the globe with confidence.

At the same time, governments were increasingly willing to send expeditions to explore those vast areas of the globe that were still unknown. Emphasis was concentrated on the Pacific and on the polar seas. Captain James Cook’s first voyage (1768-71) was undertaken to observe the transit of Venus across the face of the sun in the South Seas, but revealed valuable information about the coastline of New Zealand and Australia . . . Cook’s second voyage (1772-75) was explicitly undertaken to determine the extent of the southern land masses . . . Although ostensibly in search for pure knowledge, the Admiralty sent Cook and other explorers out in part of nationalistic reasons . . .

By the end of the century, those parts of the world accessible by sea had been largely explored. Only the polar regions remained, and the search for the North West Passage from the Atlantic to the Pacific to the north of Canada was to cost explorers’ lives well into the nineteenth century. The interiors of the continents were not so well known. The western parts of North America remained largely unexplored by Europeans until the early nineteenth century . . . [natural philosophers on these voyages] were determined to study the forces that shape the environment.

These studies were undertaken in the spirit of the Baconian programme that inspired early members of the Royal Society. The programme would involve detailed investigation of the air, the water and the land itself, but was often linked to theoretical questions arising from the physical sciences. The revolution in physics led to a debate on the shape of the earth, which was only resolved in the 1730s when the Académie des Sciences sponsored expeditions to Peru and to the Arctic to measure the length of a three-degree meridian arc. The results confirmed that the Newtonians were correct in their prediction that the earth was flattened slightly at the poles . . .

In the meantime, if there were efforts to provide a comprehensive ‘theory of the earth’, they came from the introduction of a historical dimension. The natural philosophers of the late seventeenth century devoted a great deal of effort to the study of the earth’s surface. They climbed mountains and studied the rocks of which they were composed. They puzzled over the fossils found in the rocks, many of them apparently resembling marine creatures. They also investigated the natural processes that affected the earth: volcanoes, earthquakes and the effects of the various processes of erosion.

These studies generated renewed interest in the question of the origin of mountains.

It was possible to maintain . . . that the present structure of the earth’s surface was essentially the same as that originally created by God. But other scholars were inclined to believe that mountains might actually have been formed by natural processes at the time of Noah’s flood. This would account for the fossils contained in stratified rocks, which could be interpreted as deposits laid down when the earth had been covered with water. But was it possible that the shape of mountains was changed by natural processes after they had been formed? The effects of volcanoes and of denudation by rivers and streams suggested that processes were still at work that could profoundly alter the surface of the earth.

The ultimate product of these investigations was a rash of theories attempting to explain the existing structure of the earth in terms of natural processes operating through time . . . [103-110]

[The Origin of the Earth]

The resulting theories [of the earth’s origin] consist of a curious mixture of scientific speculation and biblical literalism. Many historians of geology have dismissed them as of little real importance on the grounds that science so bound up with religion must necessarily be unproductive. More recent assessments have adopted a less critical attitude, in part because we now recognize that most late-seventeenth-century science included similar components. These apparently clumsy speculations provided a foundation for trying to organize the ever-expanding amount of information about the earth. Building upon this foundation, the naturalists of the eighteenth century would put together an impressive array of observations throwing light on both the structure of the earth’s crust and the processes still affecting it . . . The resulting science [of geology] was often significantly different in different countries—so new a field was inevitably subject to local influences, both social and environmental . . .

The Meaning of Fossils

The observations that generated this mine of information included surveys of local landforms, revealing phenomena that seemed to indicate the power of erosion to destroy the existing features. There were also the strange objects that could be dug out of the earth . . .

For many of the naturalists who studied the earth’s crust, the most important phenomenon was the appearance of fossils within those rocks which were stratified (laid down in layers). Today we take it for granted that fossils are the remains of once-living things trapped in sediment that was laid down under water and then solidified to form rock before being elevated to its present position. Fossils are thus a clue to the earth’s past . . . But not every naturalist interested in the earth shared this view. Many Renaissance thinkers preferred to see fossils as the products of mysterious forces operating within the rocks. This view was still shared by some seventeenth-century fossil collectors, included the noted Welsh naturalist and traveller Edward Lhwyd (1660-1709). To him, fossils were merely natural objects to be classified along with all the other products of the earth. They carried no message about the past . . .

Lhwyd’s view was shared by Martin Lister, who pointed out that ammonites, although superficially resembling a seashell, bear no resemblance to any living mollusc. But other naturalists looked at the very close resemblance that could be seen between fossil shark’s teeth and those of the living sharks, and accepted this as clear evidence that the fossils were derived from once-living creatures. A pioneer in such studies was . . . Nicholas Steno (1638-86) . . . Steno stripped the fossils of their old symbolic meaning and treated them solely as a clue to the origin of the rocks within which they were contained. The layers of rock had once been deposited as sediment on the bottom of the ocean, with the remains of living things becoming trapped and ultimately petrified within the sediment . . . Although his views on the nature of fossils were remarkably modern, Steno had no intention of challenging the biblical story of the earth’s history. He accepted that the first period of deposition occurred immediately after the creation, while the collapse of the overlying strata constituted the great flood . . .

Steno’s theory attracted wide attention, especially in England . . . One of the leading British fossil collectors was John Woodward (1665-1728), who lectured at Gresham College in London . . . [Woodward] published very accurate descriptions of fossils, and his Essay toward a Natural History of the Earth of 1695 offered an extension of Steno’s explanation of how they were formed. Woodward supposed that the whole of the earth’s original surface was destroyed at the time of the deluge, the material subsequently settling out of the water to form the layers of stratified rocks. He noted that particular fossils are found only in certain types of rock . . .

One critic [of Woodward] was the eminent naturalist John Ray (1627-1705), who postulated both a deluge and earth movements caused by underground explosions to account for the present state of the earth . . . [His] most active theological concern was the threat that fossils seemed of offer to the notion of divine providence. Ray believed that all species were designed by a wise and benevolent Creator, implying that the world is static and unchangeable. Yet if ammonites were once living shellfish, they must have become extinct, thus leaving a gap in the plan of creation . . . Ray could thus see points in favour of Lhwyd’s claim that fossils were not organic remains. It was by no means easy to accept that God’s creation was subject to change . . .

It was Robert Hooke (1635-1703) who made the boldest effort to explore the consequences of the new discoveries in his Discourse of Earthquakes (completed in 1668 but not published until 1705). Hooke was convinced of the organic origin of fossils, having used the microscope to compare the structure of fossil and living wood. He thus shared Steno’s view that the fossils were the remains of once living things trapped in sediment . . . Hooke had little patience with those who saw all the sedimentary rocks as the remains of Noah’s flood . . . He was prepared to accept that some species might have been made extinct in the catastrophes. Hooke thus moved towards the concept of a changing earth, but even he could not visualize a greatly extended timescale . . .

New Cosmologies

The drive to study the earth’s crust generated information that encouraged speculation about changes taking place on the earth . . . But not all of the ‘theories of the earth’ were based on detailed observation. This is evident from . . .the Sacred Theory of the Earth by Thomas Burnet (c. 1635-1715), published originally in 1681-89. As his title indicates, Burnet believed that the Bible should be taken seriously as a guide to the earth’s history, although we warned against following the Genesis story too closely . . .

Burnet’s book aroused both interest and antagonism among his contemporaries. It was soon followed by an alternative, more in line with the Newtonian theory, the New Theory of the Earth of William Whiston (1667-1752), which appeared in 1696. Whiston argued that the deluge was caused by a comet striking the earth. There was much opposition from conservative thinkers, who objected to the liberties Burnet and Whiston had taken with Genesis. Their arguments seemed to undermine the traditional belief that the flood was a direct (i.e., miraculous) consequence of divine anger . . . But however hard the early theorists might try to link the sequence of events to the Bible, their ideas reduced the earth itself to a material system governed only by natural law.

The philosophers of the eighteenth-century Enlightenment were increasingly willing to challenge the authority of established churches, and were thus less tolerant of the biblical story of creation. The outburst of theoretical speculation that marked the last decade of the seventeenth century left a legacy of interest in the basic problem of explaining how the earth’s surface acquired its present form, but Noah’s flood was no longer assumed to be the principal mechanism of change . . . [113-121]

QUESTIONS:

1) What the most important points made about the motivations to explore & survey the earth’s surface in the eighteenth century?

2) Evaluate the historical validity of the following: “Those who did not believe in the modern of idea about how fossils are formed were not scientists.”

3) Evaluate the historical validity of the following: “Science is NOT influenced by the society in which develops, therefore, anyone influenced by such external factors as religion or philosophy is NOT a scientist.”

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