Scaling from Weather to ClimateDaniel Liu

Geology: Enlightenment in Action

The evolutionary theorist and historian of science Stephen Jay Gould (1941–2002) wrote in 1988 that Sigmund Freud had forgotten the fourth great intellectual revolution of European scientific modernity. Freud had enumerated three: Copernicus’ de-centring of the Earth into one of a multitude of planets, Darwin’s demotion of man’s special creation into the spectrum of the descent of species, and of course Freud’s own revolution of subordinating rational action to the impulses of the subconscious. The fourth revolution, which Freud missed and Gould insisted upon, was the early nineteenth-century discovery of geological and cosmological deep time, the extension of the history of nature to millions and billions of years, in both breadth and depth.1414Stephen Jay Gould, Time’s Arrow, Time’s Cycle: Myth and Metaphor in the Discovery of Geological Time (Cambridge, MA: Harvard University Press, 1988), pp. 1–2. But it has been Martin Rudwick’s contention since his 2005 book Bursting the Limits of Time and emphasized in the 2008 sequel Worlds Before Adam that geology’s essential modernity is not in its mere extension of time, a concept other sciences have potentially entertained. Rather, Rudwick argues that modern geology embraced a very particular kind of historicity and temporality unique to the history of the geosciences. Modern geology for Rudwick — perhaps modernity generally — is characterized by emphasis on the contingency of geohistory, not just its depth. Contingency in the history of nature means, to Rudwick, that the history of nature is ‘as unrepeated, and as unpredictable, as human history itself’.1515Martin J. S. Rudwick, Bursting the Limits of Time: The Reconstruction of Geohistory in the Age of Revolution (Chicago: University of Chicago Press, 2005), p. 6. See also Rudwick, Worlds Before Adam: The Reconstruction of Geohistory in the Age of Reform (Chicago: University of Chicago Press, 2008). Modern geological theory that embraces this sense of deep historical contingency can help take local and regional rock formations and reconstruct the past in stepwise fashion. By analogy, this is akin to comparing the reconstruction of the evolutionary history of Homo sapiens to theories of the state of nature in moral philosophy: these clearly related endeavours to understand the human and the subsequent history of humanity nevertheless have totally different relationships to the distant and proximate past. This sense of historical contingency is, Rudwick argues, the product of the late eighteenth-century habit by natural philosophers to import methodological concepts from the history of Christian theology, specifically Biblical chronology, into the theories of the Earth. Without denying the importance of deep time, Rudwick’s contention is particularly useful in our general consideration of weather/weathering, in that it insists on the duality of the contingency of particular events alongside the universality of the laws that govern them.

It is perhaps easier to understand what this contingent historicity is by contrasting it with the alternative temporalities that have been extant in European intellectual history. It is also a helpful way of qualifying what Rudwick means by history being unrepeatable and unpredictable: to be more exact, this means that a genuinely contingent human history or history of nature must be directionally cumulative (and therefore unrepeatable), and it also must not be preordained. For the most part, ancient Greek and Roman natural philosophy only provided its Latinate and Arabic descendants with a conception of nature as eternal, cyclical, and governed by forces that acted out of necessity. This was particularly true in Platonic cosmology, Aristotelian cosmology, and Ptolemaic astronomy, which took the eternal rotation of the stars around the earth, and the evident perfection of circles and spheres as the archetypes for both nature and causality generally. This kind of natural philosophy stood in stark contrast with the emphasis on free will in Christian theology and the Biblical drama of salvation. One of the great tasks of European and Arab scholarship through the Middle Ages was precisely to find ways to reconcile Greek philosophy’s emphasis on the eternal on the one hand, and, on the other hand, Mosaic theology’s emphasis on both the provisional nature of God’s will and the voluntary nature of human faith. The histrionics surrounding the papal Condemnations of 1277 was but one famous episode, with church authorities alarmed by the radical Aristotelians’ claims that an eternal universe was more logically consistent than the account of creation in Genesis.1616David C. Lindberg, The Beginnings of Western Science, 2nd edn (Chicago: University of Chicago Press, 2007), chapter 10.

Additionally, the Aristotelian foundations of medieval Latin and Arabic natural philosophy provided only very crude ideas for understanding different scales of natural phenomena. Privileging the eternal, circular motion of the celestial sphere relegated the terrestrial as the realm of linear, or ‘accidental’ as opposed to perfectly circular and eternal ‘natural’ motion. The physics of the terrestrial sphere were effectively governed by the natural motions of the four elements in Aristotelian matter theory — i.e., that earth, water, air, and fire tended to sort themselves in layers, with earth ‘falling’ to the centre of the cosmos and fire rising to the interface of air and the celestial aether (e.g. in pre-Newtonian definitions of gravity). In this cosmology, the elements’ terrestrial disorder meant this overarching, law-like tendency towards order would be interrupted by the proliferation of local events and causes. The terrestrial as the realm of the accidental proved to be a source of inspiration for natural philosophers seeking to reconcile the overarching eternalist framework of Greek metaphysics with the demand for theological contingency: for example, for the Lutheran reformer and pedagogue Phillip Melanchthon (1497–1560), elucidating the providential meaning of accidents (generally, in the metaphysical sense) was an essential way of fitting the Aristotelian natural philosophical corpus into reformed Christianity based on justification by faith alone.1717Sachiko Kusukawa, The Transformation of Natural Philosophy: The Case of Philip Melanchthon (Cambridge: Cambridge University Press, 1995).

The terrestrial was therefore not historical so much as merely accidental, and terrestrial natural history was thus merely the corrupted subset of a naturally eternal cosmos. At least when it came to nature, Greek natural philosophy and its descendants up to the Scientific Revolution could explain specific natural phenomena with reference to extremely local causes and agents (e.g., in theories of vision),1818David C. Lindberg, Theories of Vision from Al-Kindi to Kepler, rev. edn (Chicago: University of Chicago Press 1996). but they were not capable of wholesale discovery, ordering, and reconstruction of events in time, deep or otherwise, according to Rudwick. In contrast, Biblical chronology, dynastic chronicles, epics, and narratives generally place events in a temporal sequence and seek to explain their sequence with any number of causes. Nor did this lack of interest in specific historical sequence substantially change during the Scientific Revolution. The introduction of the new mechanical philosophy by Descartes and the neo-Epicurean atomists in the sixteenth and seventeenth centuries managed to replace the eternalism of Aristotelian cosmology with a linear history of the universe, albeit one strongly shot through with determinism. The mechanical philosophy’s determinism was directional — linear motion was now ‘natural’, while active intervention was required for circular motion — but although it could in principle be used to reconstruct the history of the universe, in practice the mechanical philosophy’s explicitly abbreviated causality limited scientists to ad hoc guesses about particular types of geological events. These ad hoc ‘theories of the earth’ traced their lineage to Descartes own theory of the creation of mountains in his 1644 Principia Philosophiæ (part 4, sections 41–44), in which Descartes suggested mountains were caused by differential heating and cooling of the Earth by the Sun (Fig. 1). This kind of directional, if broadly deterministic theory culminated in Buffon’s theory of the cooling earth: in his Histoire Naturelle (1749–89), he argued that all of the planets formed when comets struck the Sun, tearing off lumps of superheated material that cooled as over time. Inspired by the evident fact that mines become hotter the deeper they are excavated, Buffon went as far as commissioning a blacksmith to heat iron balls of different sizes, and studied the way heat loss varied by the size of the sphere: based on these studies, Buffon argued in print that the Earth was approximately 75,000 years old, though in private he speculated that it was as high as 10 million.1919Martin J. S. Rudwick, Earth’s Deep History: How It Was Discovered and Why It Matters (Chicago: University of Chicago Press, 2014), pp. 65–66. Whatever the particular age of the Earth might be in these theories, however, they were largely based on a premise that a small set of initial conditions and mechanisms could account for the entire course of geohistorical events in a deterministic, predictable fashion, ‘from Fireball to Snowball, under the constant laws of nature.’2020Ibid. They were, by definition, global in scope, albeit ‘global’ relative to cosmology, rather than relative to anything approaching human history of human experience. This indoor theorizing was often dismissed as indulgent speculation. Nevertheless, these kinds of ‘Fireball to Snowball’ theories by Buffon and others provided for a deeper history of the Earth, now conceivably millions of years old.

They also created the first tentative link between theories of the Earth’s development with a different domain of investigation: geognosy, what today we might call stratigraphy, the description of the ordering of layers of different kinds of rocks into strata (Figure 2). In the eighteenth century and earlier, geognosy was a descriptive part of the sciences of mining and quarrying: layers of rock were studied in order to anticipate where in the Earth valuable ores or minerals could be found. In most areas, the layers of rock formed regular sequences from topsoil down to bedrock granite: mine engineers knew that these sequences of strata were fairly regular across local and even regional distances, since they had already dug into the earth or examined exposed outcrops.2121Rudwick, Bursting the Limits of Time, chapters 2 and 4. The clearly layered and seemingly orderly sequence of strata had made early geotheory plausible, and early geotheory likewise tried to mobilize the regularity of rock strata to create theories of the Earth. In what Rudwick calls the ‘standard model’ of pre-modern geology, as the Earth cools, its surface becomes a giant ocean, and further cooling causes minerals to precipitate and sediment into layers, with each layer differing due to its relative age and by its chemical composition.2222Ibid., pp. 172–74. These theories could thus explain why ‘basement’ or ‘Primary’ rocks like granite, schist, gneiss, and marble were usually found below the lighter, ‘Secondary’ rocks like sandstone, shale, and limestone. Buffon’s and other theories following the standard model could potentially take geognosy — ordinarily a descriptive, classificatory, and structural science — and transform it into evidence of the Earth’s deep history.

But the Earth is not so regular, and planetary-scale causal theories like the late eighteenth/early nineteenth-century standard model struggled to account for the increasing amounts of local variation being studied and recorded by miners, physical geographers, and mineralogists. Critics of ‘Enlightenment rationality’ tend to miss the way that amateur and expert savants in the eighteenth century also obsessively collected examples of nature’s diversity, often desiring particularly strange specimens that explicitly defied extant theories or rationalizations of nature. Strange or beautiful rocks and fossils would be removed from their original context precisely for their peculiar or exemplary character and be placed in mineralogical collections; these collected specimens could be compared by simple visual examination, through more advanced optical analysis, or even through more destructive chemical analysis. Chemical analysis could raise some uncomfortable questions about the standard model. Why, for instance, was heavy basalt so often found in strata on top of, for example, lighter sedimentary strata like sandstone or limestone? Did this mean basalt was a compressed sandstone? Or, as some geotheorists in the eighteenth century suggested, was basalt volcanic in origin — thus adding unexpected complexity to the standard model of geological history?2323Ibid., pp. 62–63.

The most broadly synthetic method of addressing these questions about the Earth’s geological diversity would, by the middle of the nineteenth century, be found in physical geography and geognosy, which, above all else, privileged outdoor fieldwork over the collection and comparison of objects. The turn of the century in Europe witnessed a unique boom in geological fieldwork, though the reasons for the boom varied in different places: in Britain it became inexplicably fashionable for leisured gentleman to explore their physical environments, while in Central Europe minor and major states alike established mining schools as a cameralistic response to the economic devastation of the Seven Years’ War.2424Ursula Klein, Humboldts Preussen: Wissenschaft und Technik im Aufbruch (Darmstadt: Wissenschaftliche Buchgesellschaft, 2015). Initially, both these amateur and professional endeavours were much alike in scale but unlike in dimension. As already mentioned, mining scientists in places like the Ore Mountains on the border of Saxony and Bohemia sought to understand the local sequence of the Earth’s strata in order to anticipate where veins of ore (and later coal) might be found before undertaking the costly work of digging mine shafts. Mining savants above all, like Abraham Gottlob Werner (1749–1817), thus sought to understand the sequence of strata on the vertical axis in particular mining districts. Strata are not simply layered in parallel sequences as the standard model — or, for that matter, the Aristotelian model — would suggest, like a cake, but rather many sit at different angles. Certain well-established strata could be found in vastly different thicknesses in different places. Most critical were unconformities, places where some strata might be layered at sharp angles to others, or a stratum is highly uneven, or perhaps missing entirely, or even found unexpectedly intruding on a predicted sequence. Some unconformities are visibly evident, others quite subtle and visible only to someone looking for it; some strata simply do not show clear orientation at all, looking more like a mass of rubble. These difficulties made expertise valuable particular in the professional setting of mining and geognosy, but amateurs could nevertheless do the basic work, since the basic instruments were quite minimal: all one needed was a hammer, shovel, a hand lens, free time, and transportation to seek out weathered cliff faces or hills with exposed layers of rock. At the same time, long personal experience with the rocks of a local region was necessary to understand all of the variation that was possible, and to discriminate between similar-looking strata, in order to correlate the sequence of formations from one place to another.2525Martin J. S. Rudwick, The Great Devonian Controversy: The Shaping of Scientific Knowledge Among Gentlemanly Specialists (Chicago: University of Chicago Press, 1985), pp. 37–54.

The mining professionals had the advantage of being able to enlist labour to dig, but they also considered their knowledge to be both relatively localized and purely descriptive: initially, geognosy was not tied to particular theories of the Earth or ideas about Earth’s history. But over the course of the first half of the nineteenth century, as more and more local areas had their strata mapped, the early geologists grew increasingly confident that they could understand the stratigraphy of whole regions by induction, without needing to direct empirical evidence from each individual locale. Moreover, the growing network of amateurs in Britain meant that studies of local formations could be compared: by 1822 the Geological Society of London counted 313 members living in or near London, and an additional 328 ‘non-resident’ members living overseas, all of whom received published Proceedings that summarized members’ reports.2626Ibid., pp. 18–27. The amateurs in Britain had the advantage of sheer numbers and a growing system of scientific sociability that could coordinate the efforts of a larger number of less-expert local explorers. These collective efforts would culminate in some of the most impressive examples of the synthesis of experiential knowledge in natural history: George Bellas Greenough (1778–1885) and William Smith’s (1769–1839) grand geological maps of regions as large as the entirety of England (Fig. 3), with Smith making his map entirely through his own surveying work. By mid-century, British geologists were crisscrossing the globe, taking advantage of global travel secured by Britain’s naval supremacy, in order to conduct intensive geological surveys in the field. The Scottish geologist Roderick Murchison (1792–1871) made expeditions to nearly every corner of the globe, from Australia to British-controlled India to the Russian Baltic: his work in stitching together the stratigraphy of so many areas of the Earth was not only in service of geological theory, e.g. determining the global distribution of the sequence of strata, but equally importantly his work aided imperial and colonial authorities in planning gold, coal, and other mining projects that ultimately sustained the imperial endeavour. At every point in Murchison’s journey, the basic tools of investigation were the same: travel to many locations, examine extant outcroppings, map and chart formations along horizontal and vertical axes.2727Robert A. Stafford, Scientist of Empire: Sir Roderick Murchison, Scientific Exploration, and Victorian Imperialism (Cambridge: Cambridge University Press, 1989).

Identifying and associating the order of strata across such large distances ultimately required more than just the examination of the rocks themselves, the differences among which could be exceedingly subtle, or, in the case of some unconformities, absent entirely. The great success of unlocking the sequence of strata across the globe owed much to the growing recognition in the nineteenth century that the order of rock strata were correlated to the kinds of fossils that geologists and geognosists found in each of the strata. The distinctiveness of the fossil bones, shells, and occasionally plants in each stratum became aids for identifying the order of strata across regions where the rocks themselves were not the same, or just hard to identify: Smith’s grand maps of the strata of England owed much to his ability to use ‘characteristic fossils’ to identify strata. But these observable consistencies across strata and fossil beds eventually became a way to understand both fossils and strata as clues for the reconstruction of a linear, progressive, and contingent history of the Earth. As early as 1801, the naturalist Georges Cuvier (1769–1832) remarked, ‘the older the beds in which these bones are found, the more they differ from those of animals we know today.’2828Georges Cuvier, ‘Espèces de quadrupèdes’ (1801), p. 260, quoted in Rudwick, Bursting the Limits of Time, p. 424. As geologists and collectors alike started to plot out where certain kinds of fossils were found — a task that required experience both out in the field and inside the museum — it became apparent that the top-most, ‘youngest’ strata bore fossils that were similar to many known living species, while fossils in deeper, ‘older’ strata were often much stranger. Whereas in the late eighteenth century early geologists had suggested that the presumably law-like character of geological change might make the history of the Earth cyclical or eternal, the fossil evidence accumulating in the early nineteenth century seemed to show otherwise. The fossils that were being found were simply not like bones of known animals, suggesting that large scale extinctions accompanied the successive deposition of rocks into strata. Moreover, as the correlations of fossil types and strata became stronger, it became possible to imagine a reconstruction of the actual past world that these fossils came from. A most dramatic case in 1822 by the English theologian and geologist William Buckland (1784–1856) demonstrated that it was even possible to reimagine not only ecosystems, but even the daily lives of animals that lived in a very distant time. The cave, discovered by miners in 1821 working in a limestone quarry in Kirkdale, in Yorkshire, was filled with fossil bones of elephants, hyenas, rats, horses, bears, oxen, and rhinoceroses. Yet both the entrance of the cave and the cave itself was too small for any of these larger animals to go in. Buckland realized that the cave must have been home to a hyena den, and that the largest bones must have been dragged into the cave by the hyenas, as shown by the toothmarks on the large bones and abundant ‘calcareous excrement’ found within the gravel and silt. The petrified dung would be the key to the reconstruction: by comparing the fossil excrement with specimens from English zoos, Buckland demonstrated that the fossils were most likely dragged in as scavenged food by the hyenas, and not washed into the cave — either by periodic flooding or by Biblical deluge.2929Ibid., chapter 8.

Buckland’s reconstruction of the Kirkdale cave made it possible to, as Rudwick puts it, ‘construct a conceptual time machine’ moving backward from recent cases into the deep past.3030Rudwick, Earth’s Deep History, p. 125. This kind of stitching together of the past from localized elements into maps and narratives stood in stark contrast to earlier attempts to create theories starting from cosmological scales. As Rudwick argues in Earth’s Deep History, by the middle of the nineteenth century geology had adopted many of its conceptual frameworks not from geophysics but rather from secular and sacred history: the coins, artefacts, and documents of history and historiography were made analogous to the rocks, fossils, and formations of geology. Although elements of this analogy can be debated, it nevertheless suggests how modern geology can be considered as a science of scaling up localized, individualized experience into grand narratives of the history of the Earth.[Rudwick, Martin]

Climatology: From Experience to Theory

The epigraph at the top of this chapter, taken from the meteorology textbook by the Austrian climatologist Julius Hann (1839–1921), highlights the fundamental epistemological difference marked by the concepts ‘weather’ and ‘climate’: we can go outside and experience the weather through our senses and instruments, but if we are to collect our experience into knowledge about the climate, then we have to resort to something other than experience. It does not follow that weather is real and climate a fiction: it simply means that the two are grasped by different means. The history of climatology and meteorology in some sense runs in the opposite direction from the history of geology and theories of the Earth. Whereas the latter began at cosmological scales and gained local-historical granularity, the sciences of weather and climate began with the assumption that local weather events were both highly variable and highly place-specific. Climate science only later acquired a theoretical generality that could tie large-scale movements of air, water, and heat together with the particularities of a local landscape.

Meteorology and weather forecasting have probably been practiced by every human society through some means, though the modern combination of ship-borne observation of navigable winds and long-term records from weather stations to analyse large-scale climatic phenomena began in the late-1700s, with the mobilization of the thermometer, barometer, and hygrometer.3131H. Howard Frisinger, The History of Meteorology: To 1800 (New York: Science History Publications, 1977). Well into the nineteenth century, alerts for potentially catastrophic weather events required someone to directly observe an incoming storm — by ship in many colonial coastal ports, by observation stations everywhere else.3232See Robert M. Rouphail, ‘Cyclonic Ecology: Sugar, Cyclone Science, and the Limits of Empire in Mauritius and the Indian Ocean World, 1870s–1930s’, Isis, 110.1 (March 2019), pp. 48–67 <https://doi.org/10.1086/702729>. The historian Richard Grove has argued that the first global climatic event to be accurately recorded was probably the Great El Niño of 1790–1794, when the British imperial officials simultaneously recorded barometric readings, droughts, and reports of crop failures in the Caribbean, northern China, Australia, Mauritius, and most critically Madras and Bengal.3333Mike Davis, Late Victorian Holocausts: El Niño Famines and the Making of the Third World (London: Verso, 2002), pp. 216–18; Richard Grove and George Adamson, El Niño in World History, Palgrave Studies in World Environmental History (London: Palgrave Macmillan, 2018), chapter 4. But noticing the simultaneity of far-flung events does not amount to noticing and naming one climatic event: in the case of the El Niño Southern Oscillation, a complete theory only emerged in the 1960s, with major revisions made through the 1980s. Until the 1870s, the gathering of data and creation of meteorological maps and tables had only a very limited theoretical payoff.3434Azadeh Achbari and Frans van Lunteren, ‘Dutch Skies, Global Laws: The British Creation of “Buys Ballot’s Law”’, Historical Studies in the Natural Sciences, 46.1 (February 2016), pp. 1–43 <https://doi.org/10.1525/hsns.2016.46.1.1>. As Deborah Coen argues in Climate in Motion, taking climatology from rules of thumb to scientific theories of global climate required new physical theories of heat as well as literary techniques for describing movement across scales.

For Coen, the Austro-Hungarian Empire was a political entity that was particularly suited for the creation of an integrated science of climatology: a contiguous land empire that encompassed many peoples, languages, and terrains. Coen argues that finding political unity in the Empire meant searching for the forces and tensions that tied together the parts into the whole through dynamics, rather than simply assuming parts are instantiations of an a priori whole or natural category.3535Coen, Climate in Motion, p. 32. Mapping and collecting, which were so crucial to British, Dutch, and Spanish imperial projects, were augmented by projects to determine why diversity persisted across an integrated space: it was important to fully catalogue local contrasts, but an additional step was needed to turn this collection of facts into scientific knowledge.3636Ibid., pp. 139–42, 153.

In Austrian climatology, the additional force came through different applications of thermodynamics in order to explain the accumulation, movement, and dispersal of atmospheric energy. For example, the Austrian geographer Alexander Supan (1847−1920) pioneered the discovery and use of pressure and temperature gradients, mapped to particular geographical regions, where atmospheric energy accumulated and dispersed along predictable lines.3737Ibid., pp. 172–74. Doing so revealed that the distribution of climatic patterns was not itself driven by measured wind speed, but rather by the movement the pressure systems that drove the wind. But by far the most important climatological theory to come out of imperial Austrian climate science was Max Margules’ (1856-1920) theory of the ‘available potential energy’ (APE) of the atmosphere.3838Ibid., pp. 199–202. Margules, a physicist at the Austrian Imperial Zentralanstalt für Meteorologie und Geomagnetismus (ZAMG), argued that the stability of pressure gradients themselves had to be accounted for by measuring the energy capacity and (thermodynamic) work done by moving masses of air and moisture. By considering the dynamics of weather as ‘pendulous oscillations’ of unequal masses of air as a first principle (Fig. 4), Margules’ APE model implies that winds, storms, and pressure gradients were caused by the movement of warm and cold bodies of air — a concept that is fundamentally a mathematical abstraction of direct experience — and that movement of warmer or colder air horizontally across the landscape has significant effects on the vertical distribution of atmospheric heat, pressure, and moisture.3939Max Margules, ‘On the Energy of Storms’, in The Mechanics of the Earth’s Atmosphere, trans. by Cleveland Abbe (Washington, DC: Smithsonian, 1910), pp. 533–95. Here was the grand unifying theory: all weather phenomena must be understood as the energetic effect of bodies of air moving across the land and up and down the atmosphere, and the terrain itself thus has a powerful effect on the movement of these masses of air. In the 1950s, the American meteorologist Edward Lorenz (1917–2008) would broaden Margules’ theory of storm generation into a general theory of atmospheric circulation, a theory that makes the movement of heat into the root cause of all weather phenomena.4040Edward N. Lorenz, ‘Available Potential Energy and the Maintenance of the General Circulation’, Tellus 7.2 (January 1955), pp. 157–67 <https://doi.org/10.3402/tellusa.v7i2.8796>; Edward N. Lorenz, The Nature and Theory of the General Circulation of the Atmosphere (Geneva: World Meteorological Organization, 1967).

Conclusion

Experience, Lino Camprubí and Phillip Lehmann argue, scales.4141Camprubí and Lehmann, ‘The Scales of Experience’. Models and theories of the climate are not generated solely by abstraction, but historically come from people observing rolling clouds near and far, measuring the fall of atmospheric pressure, feeling their skin becoming clammier as the humidity rises: the dynamic experience of the weather is not only felt by one individual, but by many, and these experiences and measurements are recorded, sorted, and eventually calculated to become the science of the climate. This is in large part because there is not one monolithic ‘experience’. Experience has different modes of feeling and seeing that are augmented by time, technologies, and, once accumulated, in expertise. The instruments and techniques of experience in early geology were collections, reports, and eventually maps and guides to landscapes. The scale of geographical and geological maps provides a good case in point: they are clearly generated by experience, but a map in the hands of its user becomes a tool to augment experience as well. The study of the cumulative and recursive effect of experiences turned into tools and representations has become one of the core tenets of empirical science studies in the twenty-first century,4242Bruno Latour, Pandora’s Hope: Essays on the Reality of Science Studies (Cambridge, MA: Harvard University Press, 1999). despite the fact that such recursiveness can lead to a sense of vertigo and disorientation.4343Coen, ‘Big Is a Thing of the Past’, p. 309.

In this essay I have tried to juxtapose two different ways experience and science scaled. In Rudwick’s studies of the history of geology, theories of the Earth originate from the Aristotelian and Cartesian theories operating at essentially cosmological scales, and much of what makes geology ‘modern’ is its contrasting ability to account for very small-scale, local variations of phenomena within the context of planetary laws. Coen’s account of the history of climatography and climatology, in contrast, begins with the historically widespread assumption of the local, small-scale specificity and variability of the weather, and only through the use of high-quality record keeping and modelling using thermodynamic laws does a picture of climatological dynamics arise. In both, the interplay of natural history and natural philosophy is centre stage, and one does not operate well without the other.

But what are we to make of the kinds of distant theorizing and exploration of nature, which in both of the cases presented here is conceptualized largely as a world prior to or absent the human species — the Anthropos and the Homo mentioned at the start of the essay? As Julia Adeney Thomas observes of Chakrabarty’s original analysis of the concept of the Anthropocene, the challenge is not only in scaling as such, which would be a problem of method and methodology in the historical sciences, but in what is being scaled. For Thomas, the distinction between Homo and Anthropos, or ‘the Human’ and ‘the human species’

is not something humanist historians can understand through self-reflection in Wilhelm Dilthey’s sense, where historical consciousness is ‘a mode of self-knowledge’, or in R. G. Collingwood’s sense, where historical comprehension rests fundamentally not on reconstructing the past but on reenacting ‘in our own minds the experience of the past.’ While ‘species’ may work for paleobiologists comparing, say, the fossil records of Eemian biota from 130,000 years ago with modern organisms, theirs is a labor of reconstruction as opposed to one of self-reflection or mental reenactment.4444Thomas, ‘History and Biology in the Anthropocene’, p. 1592.

I would like to close this meditation on weathering by suggesting that this disjuncture Chakrabarty highlights between the human as a political actor and humanity as a planetary force is loosely analogous to the distinction between the self-reflective subject and the self-negating analyst. During the early-1990s debates on historical and scientific objectivity, the historian Thomas Haskell argued that attempts to cast the concept of objectivity itself as both fictional and disingenuous ran the risk of turning any historical scholarship into propaganda, and any possible utterance into an expression of will:

But to shrug off the capacity for detachment as entirely illusory — to claim that since none of the standpoints the self is capable of imagining are really that of ‘the other’, but are self-produced (as is certainly the case), and to argue that all viewpoints therefore are indistinguishably contaminated by selfishness or group interest or the omnipresent Nietzschean will — is to turn a blind eye to distinctions that all of us routinely make and confidently act upon, and thereby to blur all that distinguishes villainy from decency, veracity from mendacity, in everyday affairs. Not to mince words, it is to defame the species. Fairness and honesty are qualities we can rightfully demand of human beings, and those qualities require a very substantial measure of self-overcoming.4545Thomas L. Haskell, ‘Objectivity Is Not Neutrality: Rhetoric Vs. Practice in Peter Novick’s That Noble Dream’, History and Theory, 29.2 (May 1990), pp. 129–57 <https://doi.org/10.2307/2505222>.

Since these debates, historians of science have argued that objectivity is itself a historically specific kind of subjectivity and set of values that scientists work to cultivate, so much so that objectivity has itself become essentially synonymous with scientific knowledge and practice.4646Lorraine Daston and Peter Galison, ‘The Image of Objectivity’, Representations, 40 (1992), pp. 81–128; Theodore M. Porter, ‘The Objective Self’, Victorian Studies 50.4 (2008), pp. 641–47; Jimena Canales, A Tenth of a Second: A History (Chicago: University of Chicago Press, 2009). Haskell argues that the species — Stockhammer’s Homo — must be capable of some kind or kinds of detachment, alienation, impartial judgement, and empathy towards the other, and this itself requires a degree of personal cultivation. It is precisely this recasting and scaling-up of the personal experience of the weather to a global understanding of climate, and the scaling-down of geological theory to understand one’s local landscape or patch of the Earth, that demands personal experience as well as alienation from it.