PRINCIPLES OF GEOLOGY

CHARLES LYELL was born in November 1797 at Kinnordy House near Kirriemuir, Forfarshire, Scotland, and was the son of a botanist. His family moved to Hampshire, on the border of the New Forest, before he was one year old. Lyell was educated at Ringwood, Salisbury, Midhurst and Exeter College, Oxford, from which he graduated in classics in 1819. He entered Lincoln’s Inn to study law, but a weakness in his eyes temporarily prevented him from continuing, a difficulty which increased in later years. He published his first scientific papers in 1825 and in the following year became a Fellow of the Royal Society. Lyell also began contributing to the Quarterly Review and gradually abandoned legal practice, having found his vocation in authorship. The first volume of his masterpiece Principles of Geology was published in 1830, and the second and third volumes appeared in 1832 and 1833 respectively. Lyell’s vision of a world shaped by uniformly acting natural processes became central to public controversy about the place of human beings in nature. Its impact is evident in a wide range of Victorian literary, philosophical and scientific works, notably those of Charles Darwin, who became a close friend. In 1831 Lyell was appointed a professor of geology at King’s College, London (although he soon resigned), and a year later he married Mary Horner, who assisted in his work and became a leading hostess in metropolitan intellectual society. He was elected President of the Geological Society of London in 1835–7 and 1849–51. A great admirer of the United States, Lyell lectured extensively there, and in 1845 and 1849 he published lively descriptions of his travels in North America. He continued to revise Principles of Geology, which appeared in its final two-volume form in 1867–8. Among his other books, all of which appeared in many editions, are Elements of Geology (1838) and The Antiquity of Man (1863). He was knighted in 1848 and became a baronet in 1864. His health deteriorated rapidly after the death of Lady Lyell in 1873, but he continued with research until his death in 1875. He is buried in the nave of Westminster Abbey.

JIM SEGORD is a lecturer in the Department of History and Philosophy of Science at the University of Cambridge. Born in Madison, Wisconsin, he studied geology, literature and history at Pomona College and Princeton University, and has lived in England since 1980. He is the author of Controversy in Victorian Geology (1986), editor of Robert Chambers’s Vestiges of the Natural History of Creation (1994) and co-editor (with N. Jardine and E. Spary) of Cultures of Natural History (1996).

Charles Lyell

PRINCIPLES OF GEOLOGY

Edited with an introduction by
JAMES A. SEGORD

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First published 1830–33
This selected text published in Penguin Classics 1997

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ISBN: 978-0-14-193680-2

List of Illustrations

Introduction

List of Illustrations^*

VOLUME I

Frontispiece. – This representation of the present state of the Temple of Serapis has been carefully reduced from that given by the Canonico Andrea de Jorio in his ‘Ricerche sul Tempio di Serapide, in Puzzuoli.’ Napoli, 1820

1. Transverse section of the Italian peninsula

2. Diagram explanatory of the sinuosity of river-courses

3. Diagram showing the recent excavation of lava at the foot of Etna by the river Simeto

15. Chart and section of Santorin and the contiguous islands in the Grecian Archipelago

16. View of the Isle of Palma, and of the Caldera in its centre

17. View of the cone and crater of Barren Island in the Bay of Bengal

18. Supposed section of the same

19. Deep fissure near Polistena in Calabria, caused by the earthquake of 1783

20. Shift or ‘fault’ in the round tower of Terranuova in Calabria, occasioned by the earthquake of 1783

21. Shift in the stones of two obelisks in the Convent of S. Bruno

22. Fissures near Jerocarne in Calabria, caused by the earthquake of 1783

27. Landslips near Cinquefrondi, caused by earthquake of 1783

30. Ground plan of the coast of the Bay of Baiæ in the environs of Puzzuoli

31. Two sections, the one exhibiting the relation of the recent marine deposits to the more ancient in the Bay of Baiæ to the north of Puzzuoli, and the other exhibiting the same relation to the south-east

32. View of the crater of the great Geyser in Iceland

33. Supposed section of the subterranean reservoir and pipe of a Geyser in Iceland

VOLUME II

Frontispiece. – View of part of the Valley del Bove, on the East side of the great Cone of Etna [Part of a panoramic drawing made by Lyell in 1828, this appeared in the first edition with hand-colouring – Ed.]

4. Maldiva Isles

5. View of Witsunday Island

6. Section of a coral island

7. Ditto of part of a coral island

VOLUME III

Frontispiece. – View of the volcanoes around Olot, in Catalonia [From a sketch by Lyell, which appeared in the first edition with hand-colouring and an accompanying geological key – Ed.]

1. Diagram showing the order of succession of stratified masses

2. Diagram showing the relative position of the Primary, Secondary, and Tertiary strata

3. Diagram showing the relative age of the strata of the Paris basin, and those of the basin of the Loire, in Touraine

4. Diagram showing the same in the strata of Suffolk and Piedmont

17. Wood-cut showing the great valley on the east side of Etna

19. View of dikes at the base of the Serre del Solfizio, Etna

20. View of tortuous dikes or veins of lava, Punto di Guimento, Etna

21. View of the rocks Finochio, Capra, and Musara, in the Val del Bove

22. View from the summit of Etna into the Val del Bove

Introduction

‘The great merit of the Principles,’ Charles Darwin once said, ‘was that it altered the whole tone of one’s mind, & therefore that, when seeing a thing never seen by Lyell, one yet saw it partially through his eyes.’¹ 1 Lyell’s Principles of Geology shaped Darwin’s vision of nature as he circumnavigated the globe on the Beagle and as he later created his theory of evolution. Modern ecologists have looked to Lyell as an important interpreter of the economy of nature. He provided the starting point for the American conservationist George Perkins Marsh, whose Nature and Man of 1864 contested Lyell’s claim that human impact on the landscape was minimal. The Principles continues to inform debates ranging from the death of the dinosaurs to the possibility of environmental catastrophe. As evolutionary biologist, geologist and historian Stephen Jay Gould has said, Lyell ‘doth bestride my world of work like a colossus.’²

The Principles, as Darwin recognized, is about seeing. In it, theology, political economy and the philosophy of perception are united with natural history, anthropology, geography and travel. The title proclaimed heroic ambitions – no less than doing for the study of the earth what Isaac Newton had done for astronomy and natural philosophy in the Principia Mathematica (1687). Practitioners, Lyell argued, should carry out their investigations under the assumption that causes now visible around us (volcanoes, rivers, tidal currents, earthquakes, storms) are of the same kind that have acted in the past, and have done so with the same degree of intensity as in the present. In the Principles, uniformity was not a theory about the actual history of nature, but a policy for securing the philosophical foundations of geology: Lyell aimed to define, as he said in a letter, the ‘principles of reasoning in the science’.³

When first published in three volumes from 1830 to 1833, the Principles attracted a wide range of readers in Europe, America and Australia, from explorers and engineers to poets and artists. Celebrated for its startling analogies and the elegance of its prose, it compares in significance to writings by Thomas Carlyle, Thomas De Quincey and Thomas Babington Macaulay. Alfred Lord Tennyson brought its themes of universal decay and the vastness of time into The Princess (1847) and In Memoriam (1850). In prison for blasphemy in 1842, the atheist agitator Charles Southwell asked for a copy along with his accordion and some cigars.⁴

The Principles can be and has been read in different ways and in different places. For any book to survive as a classic, it needs to escape its intended audience, to be used for purposes that the author never could have foreseen. But many readings of Lyell’s work narrow its meaning. The Principles is often seen solely as a precursor to Darwin’s On the Origin of Species (1859) – a view that would have surprised Darwin himself. Even more implausibly, the Principles is sometimes read as the work that created the modern earth sciences, established their first ‘paradigm’, or somehow ‘discovered time’. Alternatively, historians who recognize that geology was a seriously researched subject in 1830 tend to ignore the widespread acknowledgement by Lyell’s contemporaries of his role in establishing its philosophical credentials in the English-speaking world. The reception of the Principles is poorly understood, so that it is hard to see why the book had such a significant impact on literature and the arts. Only five or six reviews are generally thought to have appeared in Britain, when in fact there were over thirty.⁵ Lyell wrote for a wide audience, and his book needs to be seen as part of public controversies about the reform of knowledge.

I

The Principles is often read as a Victorian work, but its origins are in the Romantic era, in the religious, political and literary history of the Regency. The first edition belongs on the shelf with De Quincey and Scott, not Dickens and Darwin. Its foundational project marks the book as part of political debates that culminated in the 1832 Reform Bill.

Lyell was born in 1797, during one of the most turbulent decades of European history, and grew up under the shadow of the French Revolution and fears of foreign invasion. The Revolution, with its ferocious anticlericalism and religion of Reason, was widely traced to the works of Thomas Paine, Baron d’Holbach, Jean-Jacques Rousseau, Voltaire and other Enlightenment writers. Although Britain escaped revolution, campaigns for press freedom, repeal of restrictive taxes and Catholic emancipation were widespread. The reform of Parliament, condemned by many in the middle and working classes as corrupt and unrepresentative, became the key issue. In this setting, any argument for the constancy of natural laws was bound to create controversy.

Lyell’s father Charles was a wealthy gentleman and opponent of reform, who had inherited a large estate in Scotland. He was a Dante scholar and keen botanist. The young Charles Lyell, both on the family estate and at his childhood home in Hampshire in southern England, grew up in a cultured environment typical of the moderate Tory gentry, who aimed to adapt the best traditions of church and state to changing circumstances. When Lyell matriculated as a gentleman commoner at the age of seventeen at Exeter College, Oxford, classics and theology dominated the curriculum, as might be expected at an institution devoted to the Establishment. Lyell read classics and his writing received sufficient praise for him to think of winning prizes and becoming a poet. His interest in natural history developed through browsing in his father’s library, where he read Robert Bakewell’s Introduction to Geology in 1816.

Geology was lively, popular and controversial, a product of the more general transformation of the study of nature in the decades around 1800. Its practices had been freshly confected from cosmological theorizing, mineral surveying, natural history collecting, biblical exegesis and continental mining traditions. Like other natural history disciplines in the first three decades of the century, geology engaged a network of practitioners ranging from physicians and aristocrats to engineers and farmers. A focus on strata, as exemplified in the publications of the Geological Society of London, founded in 1807, gave these diverse constituencies a practical programme of research and a common goal.

In being open to so many, however, geology was in danger of gaining a reputation for philosophical promiscuity. Underlying disagreements about wider issues could erupt into speculative excess or religious scepticism. For all the focus on strata, public debate about the meaning of geology remained embedded in controversy about Creation, the Fall and the Flood, as illustrated by Byron’s notorious unperformed play Cain (1821). Who was to interpret the meaning of a science whose findings could so flagrantly be used to contradict the opening verses of the Bible? How was a scientific view to be given of the history of life which did not lead to soul-denying materialism and atheism?

Geology had been introduced at Oxford to arm undergraduates against the infidels, and like other natural sciences it was an extracurricular option which did not lead to a degree. Lyell attended the flamboyant lectures of the Rev. William Buckland, whose daring reconstructions of extinct monsters and lost worlds attracted an enthusiastic following. Buckland stressed ties to classical learning and agricultural utility; and because many feared that the new science undermined the truth of the Mosaic narrative in Genesis, he contended that geology evidenced divine design and a universal Deluge. The result was a romantic vision of the progress of life through countless ages, strange animals perfectly adapted to even stranger physical conditions, and culminating in the creation of the human race. The earliest articles Lyell wrote show how much he had learned from Buckland about reconstructing extinct animals, dating strata by fossils and charting the progressive history of life.

By the early 1820s Lyell had graduated and moved to London so that he could prepare to become a barrister. Poor eyesight and ambitions to shine in literary circles led him to shift his career to science, despite his father’s worry that he was abandoning a secure profession. In centring his identity around geology – while hoping to make money from it – Lyell was doing something new. Most activities that might be called professional in science during the early nineteenth century were seen as low status, involving specimen-selling, instrument-making, curating collections and hack writing. Lyell hoped to raise authorship into a calling fit for gentlemen, much as the mathematician and natural philosopher John Playfair had done through scientific reviewing and as Carlyle and Macaulay were doing through their celebrated essays. Conversely, gentility itself was to be redefined around notions of intellectual leadership. The major quarterlies, especially the Edinburgh and Quarterly, played a crucial part in defining this new role for the author.

Living in the metropolis Lyell associated with ‘Lawyers, Geologists & other sinners’⁶ and moved away from the moderate Toryism of his family. By the mid-1820s he had become an ardent liberal Whig, advocating electoral reform and disestablishment of the Anglican church. His experience of the ancient universities, which he thought were in a bad way, was instrumental in his change. To his mind only reform could salvage the established order from the horrors of ‘mob-rule’. Although his privileged background shielded him from the rawer aspects of day-to-day political struggles, they could not be ignored. Lyell witnessed violent revolutionary demonstrations in Paris, while in Scotland an angry crowd stoned a carriage carrying his sisters, who were hated as Tory gentry.⁷

The most immediate conflicts which Lyell faced were within his family, for his father and brothers had no sympathy for reform. At a crucial by-election in Forfarshire in 1831, when the rest of the family canvassed for the Tories, Lyell confronted a difficult choice. He could not violate his beliefs by voting Tory; but neither could he slight his father by siding with the Whigs, at the height of the Reform Bill agitation and in an open election with less than a hundred voters. Lyell abstained.⁸

Similarly, in devoting himself to science Lyell believed that he had found a vocation that could be used to escape the strife of ordinary affairs. The study of nature was presented as politically and theologically neutral. ‘As for public affairs,’ he told his fiancée Mary Horner (herself from a famous family of reforming Whigs), ‘I have long left off troubling myself about them, as knowing that one engaged in scientific pursuits has as little to do with them, in point of influencing their career, as with the government of hurricanes or earthly motion…’⁹ For Lyell, science offered an indirect way of forwarding reform without betraying his father or his teachers. Since a gentleman’s right to independent judgement was acknowledged, he remained welcome both at home and in fashionable Tory circles in the metropolis. The centre of his social life was the Athenaeum, a club for literary, scientific and artistic gentlemen formed in 1824 by the President of the Royal Society, Humphry Davy, and the Tory politician and reviewer John Wilson Croker. It grew out of meetings in the Albemarle Street premises of the publisher John Murray and encouraged the dominance of British intellectual life by clubbable gentlemen.

Lyell put his family connections and strategic place on the political map to good use, taking the battle for reform into what he now privately saw as the enemy camp. When he briefly assumed an academic chair as part of his campaign to become a new kind of professional man of science, it was at King’s College, founded by Anglican Tories to counter the utilitarian University of London. Lyell reviewed for the Tory Quarterly, not the Whig Edinburgh, where reforming views on education and science had been trumpeted for decades. He brought out his book with Murray, a Tory publisher, not with the useful knowledge merchant Charles Knight. Lyell of course knew about a much wider spectrum of political and religious groups, from radical socialists to the millenarian followers of Edward Irving and Joanna Southcott. But the first edition of the Principles was not written for any of these; instead, it targeted a conservative and respectable readership, made up of gentlemen and ladies who feared that geology was anti-Bible and anti-Christian, and needed to be convinced that science had nothing to do with materialism. He hoped to reach an audience among the gentry, aristocracy and professional classes who might be familiar with his early reviews. Behind the scenes Lyell manoeuvred to get sympathetic reviewers for his book in the Quarterly and the religiously orthodox British Critic. ‘It is just the time to strike,’ he told his ally George Poulett Scrope, ‘so rejoice that, sinner as you are, the Q. R. is open to you.’¹⁰

Murray, publisher of both the Quarterly and the Principles, became one of Lyell’s greatest assets. Murray wished to counteract the Whig-dominated Society for the Diffusion of Useful Knowledge, on whose behalf Knight and others were flooding the market for cheap books with inexpensive ‘libraries’ of Entertaining Knowledge and Useful Knowledge. (Knight in term aimed to stamp out the illegal ‘cheap trash’ from radical working-class publishers.) The chief monument of Murray’s efforts was the Family Library, fifty-three volumes of original non-fiction issued between 1829 and 1834. The aim of the Family Library, as Scott Bennett has argued, was counter-revolutionary; it embodied ‘a remarkable effort to publish across class lines at a time when class divisions were newly felt to be threatening the fabric of national life’.¹¹

At five shillings each the little Family Library volumes were much cheaper than the three octavo volumes of the Principles, each of which cost about four times that price. But Murray instantly recognized the affinities of Lyell’s project with his own ambition to beat the useful knowledge publishers at their own game. ‘There are very few authors, or ever have been,’ Lyell reported him as saying, ‘who could write profound science and make a book readable.’¹² Murray made sure that the third edition (the first reissuing of the whole work) was in a cheap format of four small volumes, priced at just six shillings apiece. The Principles could then compete effectively and push hack compilers out of the market. This strategy accorded with Lyell’s own financial demands – he needed big sales to maintain his gentlemanly style of life – and with his lofty conception of the man of science as arbiter of truth. He had originally planned his book as a series of didactic ‘conversations’ of the kind popular at this time and ‘instructing the millions’ remained his lifelong mission.

Lyell thus hoped to encourage the creation of an enlightened clerisy of truth-seekers – like himself – who would diffuse knowledge to the ‘vulgar’. This élitist, authoritarian vision of ‘popular science’, increasingly dominant from the 1830s, contrasted with older traditions in natural history, which had encouraged participation by a wide range of people in the making of knowledge. These paternalist practices were embodied in the vast correspondence networks of the botanist Joseph Banks, the mineralogist Robert Jameson and Lyell’s own father.¹³ Young Lyell, in contrast, tended to dismiss provincials, colonials, women and working people as mere sources of information, whose facts gained meaning by being drawn together and reasoned upon by the few. (Irate colleagues in America, tired of an itinerant bigwig plying them for hard-won findings, nicknamed him ‘The Pump’.) Lyell saw no need for ordinary readers to master all the research and reasoning that had gone into the making of knowledge; rather, experts should ‘communicate the results, and this we are bound to do’.¹⁴

The liberal Whig weekly Spectator agreed, stressing the moral value of the Principles:

The earth is an old reformer; her constitution has been subjected to innumerable changes; the signs of radical movements are to be detected everywhere, yet it is by no means easy to ascertain either the course or the causes of the revolutionary phenomena that so perpetually meet the eye of the inquirer. There are other investigations which more nearly affect our social happiness than the philosophy of geology, but perhaps there is none which in an indirect manner produce a more wholesome and beneficial effect upon the mind… After the perusal of Mr. Lyell’s volume, we confess to emotions of humility, to aspirations of the mind, to an elevation of thought, altogether foreign from the ordinary temper of worldly and busy men… So disposed mentally, the heart overflows with charity and compassion; vanity shrivels into nothingness; wrongs are forgotten, errors forgiven, prejudices fade away; the present is taken at its real value; virtue is tried by an eternal standard. There are sermons in stones and tongues in brooks, but they want an interpreter: that interpreter is the enlightened geologist. Such a man is Mr. Lyell.¹⁵

Only if a science was gentlemanly, disinterested and apolitical could it take its place as a force for reform.

II

Making science ‘philosophical’ was a way of making it respectable. Lyell’s ambitions need to be understood in the light of the contested character of knowledge at the time he wrote. Geologists had to demonstrate, through introductory books, tracts and sermons, that they could go beyond strata-hunting to treat sensitive issues safely. Published at a pivotal moment in the public history of the sciences in Britain, the Principles was the most thoroughgoing and sophisticated of these vindications. More than any of his associates, Lyell worried that an impressive edifice of practical research could be accused of resting on shaky foundations. In the specific sense of research conducted according to clearly articulated rules of reasoning (such as those in Newton’s Principia), he believed that geology was not a science. His ambition was, single-handedly, to make it one.

What did it mean to attempt to make a subject into a science in 1830? The subtitle announced how Lyell planned to go about his task. Most geological works offered a connected narrative of progress; or they were historical in the older, descriptive sense of ‘natural history’. In contrast the Principles was a treatise on natural philosophy, what the subtitle called ‘an attempt to explain the former changes of the earth’s surface, by reference to causes now in operation’. The key word here was ‘causes’. Lyell, like Newton, depended on the notion of a vera causa or ‘true cause’, defined as a cause in operation which could be observed. The notion of a vera causa had been developed in the eighteenth century by Scottish common sense philosophers such as Thomas Reid, to whom Lyell was much indebted through the writings of john Playfair and Dugald Stewart.¹⁶

Three rules of reasoning underpinned Lyell’s proposals for reforming the perceptions of his readers. First, geologists must assume that the basic laws of nature (such as gravity) had not changed over time. The sole exception was the origin of new species, where Lyell was non-committal, claiming that the human span of observation has been too short. Even here, though, he left open the possibility of an explanation through natural law; thus there might be a middle way between creation and evolution. Since, however, there was no observable basis for theorizing on this issue – no vera causa – Lyell’s genteel silence on these alternatives appeared consistent with his philosophical position. Almost all geologists accepted the constancy of the laws of nature, an assumption that directly tied the Principles with the Principia.

The second proposed rule of reasoning involved the kinds of causes to be used in interpreting the earth’s past. Here Lyell took a far more controversial stance, arguing that no causes other than those that we can now see acting should be employed in explanations. Of course, he recognized that different causes from those occurring now might be responsible for the past condition of the earth; almost all of his fellow practitioners thought that this was the case. But the Principles argued that such causes could be part of science only if they were observed by reliable witnesses. Recourse to such causes, without the backup of trustworthy testimony, encouraged investigators ‘to cut, rather than patiently to untie, the Gordian knot’ (p. 355). Lyell’s scientific critics complained that this was unduly restrictive: why assume that human observation was the only measure of untold eons of earth history?

Most surprising of all, Lyell argued that interpretation must proceed on the basis that causes had not varied in degree either; in short, the intensity of observable earthquakes, volcanoes, floods and other geological agents should be the measure of their action in the past. Again, knowledgeable commentators such as the Rev. Adam Sedgwick of Cambridge pointed to twisted mountain strata and giant erratic boulders as good evidence for episodes of ‘feverish spasmodic energy’ against which modern causes paled into insignificance.¹⁷ Quiet stasis was punctuated by violent catastrophe and sudden death. But for Lyell, recourse to such unobserved events had made geology a byword for unrestrained speculation. We can see, he claimed, forces adequate to produce the Andes and the Alps, especially if the cumulative effects of time were taken into account.

Lyell developed the implications of this policy in opposition to some of the best-supported generalizations of his fellow geologists. In early reviews he had agreed with their advocacy of progress – invertebrates giving way to fish, reptiles, mammals and then man. But in the Principles he switched sides to argue that this was an unphilosophical assumption which ignored the patchy nature of the fossil evidence. Where most geologists dreamed of filling in the lost page in the book of life, Lyell believed that they should work under the assumption that almost the entire volume had been destroyed. Gaps in the record, such as that between the Cretaceous and Tertiary, might represent vast ages, longer than the Tertiary itself. Similarly, the absence of the remains of mammals, birds and other ‘high’ forms from the very oldest rocks did not necessarily mean that such creatures had not lived then; their remains just might not have been preserved. (This suggestion was not unreasonable, as the discovery of a fossil opossum from the so-called ‘Age of the Reptiles’ had already demonstrated that mammals had existed long before geologists had thought possible.)

While denying any need to assume progress within the history of life, Lyell accepted that hotter temperatures had probably prevailed in the past. How was this to be explained while preserving the rigorous application of his rules of reasoning? He needed to show that climate changes could have been produced by the ordinary action of observable causes – not by a comet or a change in the earth’s axis (a cause differing in kind) nor by a cooling earth (a cause differing in degree). His solution, given pride of place in his first volume, was one of the triumphs of the Principles. Deploying a geographical argument, Lyell showed how shifting relations between land and sea could produce the required changes. As he told the surgeon Gideon Mantell, he had ‘a receipt for growing tree ferns at the pole, or if it suits me, pines at the equator; walruses under the line, and crocodiles in the arctic circle’.¹⁸

With such arguments Lyell rejected the possibility of constructing any continuous ‘story of the earth’ at all; in this specific sense the Principles was profoundly ahistorical. The sole defining narrative event, he claimed, was the advent of the human race. Denying any shape to earth history kept humans special because as moral beings they were separate from the rest of creation and outside the reign of natural law. Within the random, shifting balance of forces, the uplift of mountains and the erosion of coasts, the creation of humanity marked the beginning of one era and the end of another; for human origins were kept outside the physical flux that constituted earth history. Notably, human history provided the only sustained forward narratives in the Principles, and these were militantly Whiggish, developmental and progressive. Thus the ‘historical sketch of the progress of geology’ in the first volume and the history of Tertiary geology in the third celebrated the triumph of truth in Lyell’s own system.

The earth, according to Lyell, exhibited no such signs of progress. He underlined the lack of direction by speculating on the future, when a warmer climate might once again prevail. ‘Then might those genera of animals return,’ he wrote, ‘of which the memorials are preserved in the ancient rocks of our continents. The huge iguanodon might reappear in the woods, and the ichthyosaur in the sea, while the pterodactyle might flit again through umbrageous groves of tree-ferns’ (p. 67). This is often taken to mean that Lyell advocated a cyclical theory of earth history. (A cartoon privately circulated by one of Lyell’s opponents showed a future ‘Professor Ichthyosaurus’ lecturing to an audience of reptiles on the comparative anatomy of the extinct human race.)¹⁹ However, the conditional ‘might’ in this famous passage shows that there was no reason why such changes must or will come about. For all his romantic evocation of the return of the pterodactyls in a cycle of a ‘great year’, Lyell’s substantive claims were models of philosophical caution.

This point needs to be stressed, for many of the best modern commentators on the Principles – notably Reijer Hooykaas, Martin Rudwick and Stephen Jay Gould – have taken Lyell’s public statements about the pattern of earth history out of context, reading them in terms of private letters and journals so that their function as thought-experiments about the past is obscured. Lyell’s recommendations in the Principles about method are turned into doctrines or ‘isms’ and compared with those of his contemporaries: the Cambridge polymath William Whewell began this process in the 1830s by dubbing Lyell a ‘uniformitarian’ in opposition to his own ‘catastrophism’. Recent historians have set up dichotomies between progression and non-progression, or between directionalism and steady-state, which are more nuanced but serve the same purpose. They make the Principles a cosmological book, which points towards the construction of a connected narrative history of the world. However, in his public statements during the 1830s Lyell no more advocated a steady-state, cyclical or non-progressionist cosmology than he did progression itself. Indeed, the Principles claimed that any kind of global narrative would prove impossible to reconstruct, as too much of the record had been lost. Lyell, despite what Gould has argued, was not the ‘historian of time’s cycle’.²⁰

Lyell’s public application of his principles was thus almost entirely regulative: that is, geologists should carry out their investigations as though visible causes are the same kinds as those that have acted in the past, and of the same degree of intensity. Uniformity of law, kind and degree had to be assumed, Lyell argued, to make geology scientific. His subtitle cautiously spoke of ‘an attempt’ to explain former changes; and the third and all subsequent editions softened this still further. In essence, he hoped to make the study of the pre-human past amenable to the same rules of inductive inference that continental scholars, notably the great historian of Rome, Barthold Georg Niebuhr, were using to put the study of human history on a new basis. The positive aim was to make geology into an inductive science grounded in the observation of causes. Lyellian uniformity was thus a method, not a doctrine about the shape of earth history.

All his readers needed to do, Lyell argued, was to reason on what they could see everywhere around them. The sheer length of the Principles – over 1400 pages in the original edition – was essential to this programme of perceptual reform. Text and pictures, through the cumulative effect of hundreds of examples, made readers into witnesses to the power of modern changes. Large parts of the Principles (over half of the original text) were devoted to assembling a comprehensive toolkit of observed forces for use in interpreting the past. Lyell’s descriptions of rivers, tides, currents and delta-formation were so extensive that the civil engineer Sir John Rennie used the Principles as a professional reference work while constructing waterworks on the Thames.²¹ Aqueous causes were followed by a thorough account of their igneous counterparts. An entire chapter patiently documented the devastation wrought by earthquakes in one year in a single region in Italy. Lyell turned in his second volume from the inorganic realm to the organic, discussing causes now in operation involving plants and animals. The main focus was on the relation between organisms and their environment, especially in relation to geographical distribution and impact of humans and other animals in altering the face of the globe. Long chapters were also devoted to the fossilization of organisms ranging from shipwrecked sailors to corals. This kind of detailed exposition occupied a central place in Lyell’s strategy, for as Dugald Stewart had said, most people learned best from examples rather than general principles.²²

Even those who disagreed with Lyell admired the empirical richness of his book, which mustered research from hundreds of sources in five modern European languages and two ancient ones. The prestigious metropolitan weekly Athenaeum praised it as ‘one of the noblest accumulations of facts of modern times, interwoven with highly ingenious theories and truly philosophical speculations’. ‘It is essentially,’ the Scotsman newspaper noted, ‘a book of facts.’²³

Lyell drew extensively on French, German and Italian sources, for he believed that continental researchers were often far ahead of the British. Much of his history was taken (with scant acknowledgement) from Giovanni Battista Brocchi’s work on fossil conchology; information about inorganic causes derived from Karl Ernst Adolf von Hoff’s massive compilation; Augustin De Candolle was the main source for plant geography; and Gérard Paul Deshayes provided tables of shells and assisted in establishing the innovative percentage system for dating strata used in the Principles. Lyell’s greatest and earliest debt was to a group of geologists he had met in Paris, notably Constant Prévost.²⁴ These men had shown, against the celebrated naturalist Georges Cuvier, that the strata of the Paris Basin could be explained without reference to catastrophe, through comparisons with modern lakes, rivers and seas.

Lyell’s own fieldwork also impressed his readers, who were invited to picture an author climbing volcanoes, hammering chalk cliffs, measuring ancient temples and excavating fossils with his own hands. Lyell had three pieces of advice for aspiring geologists, and had followed them at every opportunity: travel, travel, travel.²⁵ Travel had been central to the making of the Principles, with tours to France, Italy and above all Sicily being critical to the shaping of Lyell’s own vision. His readers in turn gained a sense of direct contact with nature. In all this Lyell’s place in the vogue for ‘Baconian’ induction and empiricist theories of perception is clear.

Lyell’s most obvious philosophical debt was to Scottish traditions of theorizing about the earth. John Playfair, mathematician and natural philosopher at the University of Edinburgh and one of the most influential commentators on science during the Regency, had published Illustrations on the Huttonian Theory of the Earth in 1802. This work had brought the Enlightenment natural philosopher James Hutton’s system of the earth into the mainstream of nineteenth-century debate, recasting it in inductive, empiricist terms acceptable to the post-Enlightenment era. Hutton had argued for a cyclical system of strata consolidation, mountain uplift and decay, all produced by gradual forces operating under a beneficent Deity. As a natural philosopher, Playfair presented geology as a science which dealt with stable systems operating under unvarying laws. Lyell never seems to have read Hutton in the original – his quotations were all at second-hand – but he used Playfair’s works extensively.²⁶

The philosophy of the Principles is often summed up, as is that of Hutton and Playfair, as ‘the present is the key to the past.’ But this slogan is unspecific and indeed almost meaningless: causal keys can function in many ways. For example, they can license reasoning by simple analogy, which is not at all what Lyell had in mind. Rather he claimed that his key worked because present causes could be – or had been – witnessed in action by reliable observers. It was the visibility of modern causes that made them the only legitimate basis of explanation. In fact, Lyell thought that humans were not ideally placed to be good geologists: ‘an amphibious being’ would be better able to ‘arrive at sound theoretical opinions’ because so much of the earth is covered by water, while an underground gnome would be the best geological philosopher of all (p. 32). Lyell imagined such beings to make the point that any true system of the earth depended on seeing what was going on in the present.

To extend our inferences into the past, Lyell claimed, we could rely only on induction from the evidence of our eyes. Here, at a crucial point in his argument, he drew on Dugald Stewart’s Elements of the Philosophy of the Human Mind (1792–1827). ‘Any naturalist will be convinced,’ Lyell said, by the observation that ‘the same species have always retained the same instincts, and therefore that all the strata wherein any of their remains occur, must have been formed when the phenomena of inanimate matter were the same as they are in the actual condition of the earth.’ Continuity of animal instincts thus implied continuity of ‘the physical laws of the universe’, including those governing climatic change (p. 98). It was this view of instinct, drawn from the most influential British philosopher of the early nineteenth century, that underpinned Lyell’s induction about the constancy of natural laws.

The emphasis on vera causa reasoning, the philosophical heart of the Principles, appealed to views about scientific method that were widely canvassed during the decade before the Reform Bill. Lyell himself had little formal philosophical training and his references to philosophers are tactical and implicit. At Oxford he had been bored by formal logic and found Aristotle (whose writings still dominated the curriculum) ‘an astonishingly stiff author’. But he would have known that Stewart and Reid were being discussed by authors across the religious and political spectrum. At Oxford, the enlightened Tory Edward Copleston and his followers (the High Church Noetics) applied common sense philosophy as part of their project to create a Christian version of political economy.²⁷ 27 moving to London, Lyell met the young astronomer John Herschel, whose Preliminary Discourse of 1831 praised the vera causa theory of climate in the Principles. Herschel welcomed the book as ‘one of those productions which work a complete revolution in their subject by altering entirely the point of view in which it must henceforward be contemplated’.²⁸

Few reviewers were as enthusiastic about vera causa explanations as Herschel was, but almost all agreed that Lyell had transformed the philosophical status of debate in geology. Whewell celebrated the creation of a new science of ‘geological dynamics’: just as Galileo’s work on motion had led to Newton’s explanation of the planetary motion, so would Lyell’s account of terrestrial forces provide the basis for reconstructing earth history. Moreover, Lyell had proceeded ‘not in an occasional, imperfect, and unconnected manner, but by systematic, complete, and conclusive methods’. Only in this way could geology ‘be a Science, and not a promiscuous assemblage of desultory essays’.²⁹ This was high praise – even if Lyell was cast as the Galileo of geology and not its Newton.

Whewell’s approval of the Principles was widely shared. At the British Association for the Advancement of Science in 1832, the geologist William Daniel Conybeare hailed the book (albeit before launching a critical barrage) as ‘in itself sufficiently important to mark almost a new aera in the progress of our science’. The Monthly Magazine called it ‘a masterly performance’ whose publication ‘will form an epoch in the history of a science.’ The Athenaeum hailed ‘the work of no ordinary mind… a rich harvest of instruction and delight’. In an appropriate analogy, the weekly Literary Gazette praised Lyell for ‘removing much of the delta which has obstructed the current of geological knowledge’. The New Monthly Magazine, despite serious reservations based on Scripture, noted that ‘Professor Lyell’s work is the nearest approach towards establishing geology as a science, of any thing we have met with.’³⁰

No one adopted Lyell’s views wholesale, and the Principles has accordingly been presented in recent historical literature as an idiosyncratic failure, a singularity, or even ‘bad science’.³¹ It would be misleading, however, to judge the effect of the book – or the reception of any text – by the number of converts or the comments of a few specialists. As with most widely-read books, the effects were subtle and pervasive. Notably, critics of all shades of opinion agreed that debate about the earth was pursued on a new plane of sophistication as a result of the Principles. Geology could claim to be a ‘science’ worthy of the pursuit of gentlemen, according to new criteria being established at the time of the Reform Bill. Lyell’s intervention was a key part of that process.

III

The chief obstacle to a philosophical science of the earth, Lyell believed, was posed by the clergy. Nowhere was reform more overdue than in the politics of knowledge, he thought, for intellectual life in Britain was dominated by the established Anglican church. Geology could not be given principles without redefining the relations between human observation and divine revelation, between religious and secular education, between Church and State. In arguing these points Lyell saw no inherent conflict between science and theology; rather, he wished to redefine their respective domains. What was to be the relation between a new subject, largely imported from suspect continental sources, and native traditions of text-based theological criticism about earth history?

The authority of Scripture among the learned, Lyell thought, had its foundations in popular culture (or as he condescendingly said, among the ‘vulgar’). Sermons, children’s books, chronological charts on schoolroom walls, metropolitan shows, engravings of visionary paintings: the Bible structured the narrative history of the world in everyday experience. Working people were usually taught to read from the first verses of Genesis in the King James translation and assumed the literal truth of the creation story.

Lyell, eager for the dissemination of what he saw as the truth, lamented to American friends that his own nation was ‘more parson-ridden than any in Europe except Spain’.³² Thousands of clergymen preached Genesis as a matter of course, while no more than a handful (and here he included Sedgwick and Buckland) professed scientific views of the Flood or the earth’s antiquity. Of course Lyell also knew that exegetical theology had a far longer and more distinguished history than did geology, an upstart science associated with infidelity and revolutionary atheism. For most readers, the authority of Scripture continued to outweigh that of strata-maps and sections, so that biblically-oriented accounts of earth history predominated in publishers’ lists right through the first half of the century. Sharon Turner’s Sacred History of the World Books in the same tradition were written by Thomas Chalmers, Edward Hitchcock, Granville Penn, John Bird Sumner, Andrew Ure and Nicholas Wiseman – respected authors whose writings often sold more copies and were better known than those of Lyell and his friends.

PRINCIPLES OF GEOLOGY

Contents

List of Illustrations*

VOLUME I

VOLUME II

VOLUME III

Introduction

I

II

III

List of Illustrations^*