The Lying Stones of Marrakech (28 page)

As a closing example, therefore, let us return to Lyell's fascinating colleague, Charles Babbage (1792–1871), Lucasian professor of mathematics at Cambridge,
and inventor of early calculating machines that presaged the modern digital computer. The
Encyclopaedia Britannica
ends an article on this versatile genius by writing: “He assisted in establishing the modern postal system in England and compiled the first reliable actuarial tables. He also invented a type of speedometer and the locomotive cowcatcher.” So why not geology as well!

Babbage presented his studies of Pozzuoli to the Geological Society of London in 1834, but didn't publish his results until 1847 because, as he stated in a preface written in the third person, “other evocations obliged him to lay it aside”—primarily that cowcatcher, no doubt! Babbage had pursued his studies to affirm Lyell's key uniformitarian postulate, as clearly indicated in the ample subtitle of his publication: “Observations on the Temple of Serapis at Pozzuoli near Naples, with an attempt to explain the causes of the frequent elevation and depression of large portions of the earth's surface in remote periods, and to prove that those causes continue in action at the present time.”

By delaying publication until 1847, Babbage needed to add an appendix to describe the recent subsidence also noted by Lyell in later editions of
Principles of Geology
. Babbage discussed the observations of Niccolini and, especially, of Smith as reported to the Geological Society of London: “Mr. Smith found the floor of the temple dry at high water in 1819, and 18 inches on it at high water in 1845.” But Babbage then integrated these latest data with his previous observations on earlier changes in historical times to reach his general uniformitarian conclusions:

The joint action of certain existing and admitted causes must necessarily produce on the earth's surface a continual but usually slow change in the relative levels of the land and water. Large tracts of its surface must be slowly subsiding through the ages, whilst other portions must be rising irregularly at various rates.

To generalize this Neapolitan conclusion, Babbage then cited the ongoing work of a young naturalist, based on entirely different phenomena from the other side of the globe: coral atolls of the tropical Pacific Ocean. This young man had not yet become the Charles Darwin whom we revere today. (Publication of
The Origin of Species
still lay twelve years in the future, and Darwin had revealed his evolutionary suspicions only to a few closest confidants, not including Babbage.) Therefore, Babbage and the scientific community of Britain knew Darwin only as a promising young naturalist who had undertaken a five-year voyage around the world, published a charming book on his adventures and three scientific volumes on the geology of South
America and the formation of coral atolls, and now labored in the midst of a comprehensive treatise, which would eventually run to four volumes, on the taxonomy of barnacles.

Darwin's theory on the origin of coral atolls surely struck his colleagues as the most important and original contribution of his early work. Darwin, labeling his explanation as the “subsidence theory” of coral reefs, explained the circular form of atolls as a consequence of subsidence of the surrounding sea floor. Reefs begin by growing around the periphery of oceanic islands. If the islands then subsided, the corals might continue to grow upward, eventually forming a ring as the central island finally disappeared below the waves.

This brilliant—and largely correct—explanation included two implications particularly favorable to Lyell and his fellow uniformitarians, hence their warm embrace for this younger colleague. First, the subsidence theory provided an excellent illustration for the efficacy and continuity of gradual change—for corals could not maintain their upward growth unless the central islands sank slowly. (Reef corals, filled with symbiotic photosynthetic algae, cannot live below the level of penetration for sunlight into oceanic waters—so any rapid subsidence would extinguish the living reefs.)

Second—and more crucial to the work of Babbage and Lyell at Pozzuoli— the large geographic range of atolls proves that major regions of the earth's crust must be subsiding, thus also implying that other regions of comparable extent must rise at the same time. Therefore, the fluctuations recorded on Pozzuoli's pillars need not represent only a local phenomenon, but may also illustrate one of the most fundamental principles of the gradualist, nondirectionalist, and uni-formitarian mechanics of basic planetary behavior. In fact, and above all other implications, Darwin had emphasized his discovery that coral atolls do not form in regions with active volcanoes, while no atolls exist where volcanoes flourish in eruption. This mutual avoidance indicates that large tracts of the earth's crust, not merely local pinpoints, must be subsiding or rising in concert—with atolls as primary expressions of subsidence, and volcanoes as signs of uplift.

Babbage wrote to praise the young Darwin, but also to assert that he had reached the same uniformitarian conclusions independently, during his own studies of Pozzuoli:

Mr. Darwin, whose voyages and travels extended from 1826 to 1836 [
sic;
the
Beagle
voyage lasted from 1831 to 1836], was gradually accumulating and arranging an immense collection of facts relating to the formation of coral and lagoon islands, as well as to the relative changes of level of land and water. In 1838 Mr. Darwin published
his views on those subjects, from which, amongst several other very important inferences, it resulted, that he had, from a large induction of facts, arrived at exactly the same conclusion as that which it has been the chief object of this paper to account for, from the action of known and existing causes.

So far, so good—and so fair, and so just. But Babbage then proceeded further—into one of the most ludicrously overextended hypotheses ever advanced in the name of uniformitarian geology. He appended a “supplement” to his 1847 publication on the pillars of Pozzuoli entitled “Conjectures concerning the physical condition of the surface of the moon.” In Babbage's day, most scientists interpreted lunar craters as volcanic cones—a catastrophic explanation that Babbage wished to challenge. He noted that a region of lunar craters would look very much like a field of earthly coral atolls standing in the bed of a vanished sea:

The perusal of Mr. Darwin's explanation of the formation of coral reefs and of lagoon island led me to compare these islands with those conical crater-shaped mountains which cover the moon's surface; and it appears to me that no more suitable place could be found for throwing out the following conjectures, than the close of a paper in which I have endeavoured to show, that known and existing causes lead necessarily to results analogous to those which Mr. Darwin has so well observed and recorded….

If we imagine a sea containing a multitude of such lagoon islands to be laid dry, the appearance it would present to a spectator at the moon would strongly resemble that of a country thickly studded with volcanic mountains, having craters of various sizes. May not therefore much of the apparently volcanic aspect of the moon arise from some cause which has laid dry the bottom of a former ocean on its surface?

Babbage became bolder near the end of his commentary, as he explicitly wondered “if those craters are indeed the remains of coral lagoon islands.” To be fair, Babbage recognized the highly speculative nature of his hypothesis:

The proceeding remarks are proposed entirely as speculations, whose chief use is to show that we are not entirely without principles from which we may reason on the physical structure of the
moon, and that the volcanic theory is not the only one by which the phenomena could be explained.

But later discoveries only underscore the irony of what may be the greatest overextension of uniformitarian preferences ever proposed by a major scientist. Babbage suggested that lunar craters might be coral atolls because he wished to confute their catastrophic interpretation as volcanic vents and mountains. Indeed, lunar craters are not volcanoes. They are formed by the even more sudden and catastrophic mechanism of meteoritic impact.

Comprehensive worldviews like uniformitarianism or catastrophism provide both joys and sorrows to their scientific supporters—the great benefits of a guide to reasoning and observation, a potential beacon through the tangled complexities and fragmentary character of nature's historical records; but also and ineluctably combined with the inevitable, ever-present danger of false assurances that can blind us to contrary phenomena right before our unseeing eyes. Lyell himself emphasized this crucial point, with his characteristic literary flair, in the closing paragraph to his discussion about the pillars of Pozzuoli— in this case, to combat the prejudice that landmasses must be rock stable, with all changes of level ascribed to movements of the sea:

A false theory it is well known may render us blind to facts, which are opposed to our prepossessions, or may conceal from us their true import when we behold them. But it is time that the geologist should in some degree overcome those first and natural impressions which induced the poets of old to select the rock as the emblem of firmness—the sea as the image of inconstancy.

But we also know that no good deed goes unpunished and that any fine principle can turn around and bite you in the ass. Lyell had invoked this maxim about the power of false theories to emphasize that conventional preferences for catastrophism had been erroneously nurtured by the differential preservation of such evidence in our imperfect geological records. But Georges Cuvier, Lyell's French colleague, leading catastrophist, and perhaps the only contemporary who could match Lyell's literary and persuasive flair, had issued the ultimate
touché
in a central passage of the most celebrated defense for geological catastrophism—his
Discours préliminaire
of 1812.

In this manifesto, Cuvier reaches an opposite conclusion from the same valid argument about the blinding force of ordinary presuppositions. We are
misled, Lyell had remarked, by the differential preservation of catastrophes in the geological record. Cuvier held,
au contraire
, that we become equally blinded by the humdrum character of daily experience. Most moments, Cuvier argues, feature no local wars or deaths, and certainly no global cataclysms. So we do not properly credit these potential forces as agents of history, even though one global paroxysm every few million years (and therefore rarely, if ever, observable in a human lifetime) can shape the pageant of life on earth. Cuvier writes:

When the traveller voyages over fertile plains and tranquil waters that, in their courses, flow by abundant vegetation, and where the land, inhabited by many people, is dotted with flourishing villages and rich cities filled with proud monuments, he is never troubled by the ravages of war or by the oppression of powerful men. He is therefore not tempted to believe that nature has her internal wars, and that the surface of the globe has been overturned by successive revolutions and diverse catastrophes.

I must now leave these two great geological gladiators, each using the same excellent tool of reason, to battle for his own particular theory about the earth's behavior. I return then to the pillars of Pozzuoli, just down the road from the third-largest preserved amphitheater of the Roman world (where we may site those warriors for a closing image). When I visited in early January of the pre-millennial year of 1999,1 noticed a small, modern monument at one end of the Pozzuoli complex, a chipped and neglected slab of marble festooned with graffiti scrawled over a quotation with no identifying author. But I did copy the text as a good summary, less literary to be sure than the warring flourishes of Lyell or Cuvier, but equally eloquent in support of their common principle—a good guide to any scientist, and to any person who wishes to use the greatest human gift of independent reason against the presuppositions that bind us to columns of priestly or patriotic certainty, or to mountains of cultural stolidity:

Cio che piu importa e che i popolo, gli uomini tutti, perdano gli istinti e le abitudini pecorili che la millenaria schiavitu ha loro ispirato ed apprendano a pensare ed agire liberamente
.
[What is most important, is that the populace, all people, lose the instincts and habits of the flock, which millennia of slavery have inspired in them, and learn to think and act in freedom.]

4
In one of those odd coincidences that make writing, and intellectual life in general, such a joy, I happened to be reading, just two days after completing this essay, a volume of Francis Bacon's complete works. I knew the old story about his death in 1626. Bacon, who loved to perform and report simple experiments of almost random import (his last and posthumous work,
Sylva sylvarum
[The forest of forests], lists exactly one thousand such observations and anecdotes), wanted to learn if snow could retard putrefaction. He therefore stopped his carriage on a cold winter day, bought a hen from a poultryman, and stuffed it with snow. He was then overtaken with a sudden chill that led to bronchitis. Too ill to reach London, Bacon sought refuge instead at the home of a friend, the earl of Arundel, where he died a few days later.

But I had never read Bacon's last and poignant letter, with its touching reference to Pliny the Elder's similar demise in his boots—and, in the context of this essay, the ironic likeness of icy scenarios for endings: Pliny the Younger's primary invocation of darkness, and Bacon's literal encounter with cold:

My very good lord,
I was likely to have had the fortune of Caius Plinius the elder, who lost his life by trying an experiment about the burning of the mountain Vesuvius: for I was also desirous to try an experiment or two, touching on the conversion and induration of bodies. As for the experiment itself, it succeeded excellently well; but in the journey (between London and Highgate) I was taken with such a fit of casting [an old term for vomiting, from
casting
in the sense of “throwing out or up,” as in dice or a fishing line] as I know not whether it were the stone, or some surfeit [that is, kidney or gall stones, or overeating], or cold, or indeed a touch of them all three. But when I came to your lordship's house, I was not able to go back, and therefore was forced to take up my lodging here…. I kiss your noble hands for the welcome…. I know how unfit it is for me to write to your lordship with any other hand than my own, but by my troth my fingers are so disjointed with this fit of sickness, that I cannot steadily hold a pen.