The Archaean Controversy in Britain: Part III—The rocks of Anglesey and Caernarvonshire

A detailed account is given of the development of the Archaean Controversy in Caernarvonshire and Anglesey. Sedgwick had found no base for his Cambrian in North Wales, but had intimated that some of the unfossiliferous rocks of the Lleyn Peninsula and Anglesey might be older than his Cambrian. He also described two ‘ribs’ of igneous rock: one running from Caernarvon to Bangor; the other inland, parallel to the first and crossing the Llanberis Pass at Llyn Padarn. The early Surveyors (especially Ramsay) supposed that these ‘ribs’ had altered the surrounding rocks, and the resulting ‘Altered Cambrian’ could be traced across the Menai Strait to Anglesey, where it formed the various metamorphic rocks of that island. This view (which thus denied the occurrence of Precambrian on Anglesey) was challenged by the usual coalition of ‘amateurs’ (Hicks, Hughes, Bonney, Callaway, Blake, etc.) with attempts being made to recognize a sequence of Archaean rocks in North Wales similar to that in Pembrokeshire. However, vigorous debate occurred amongst the ‘Archaean’ geologists themselves, especially about a rock at Twt Hill, Caernarvon, and about a claimed unconformity at the base of the Cambrian in the Llanberis Pass, perhaps adjacent to the Llyn Padarn ‘rib’. (This was at first regarded as a Precambrian ‘island’ like those claimed at St David's, the Malverns, etc.) Vigorous debate took place about the location of the claimed Llanberis unconformity, but the ‘Archaeans’ were united in regarding the metamorphic rocks of Anglesey as Precambrian (or Archaean). Eventually, the greywackes of Anglesey, and around Bangor and Caernarvon, were identified as Ordovician, not Cambrian. Very detailed map-work in Anglesey was carried out privately by Edward Greenly, and his results were published by the Survey in the form of a map and a high-quality Memoir. Greenly utilized for Anglesey tectonic ideas derived from his earlier fieldwork in the Scottish Highlands, so that although his mapping and stratigraphical divisions have proved to be of permanent value it is believed that his structures for Anglesey were mistaken and his stratigraphic sequence inverted. The Survey eventually abandoned its earlier (Ramsay) model of Anglesey without too much difficulty; and the igneous ‘rib’ of Llyn Padarn is now construed as an ignimbrite. However, a definite base for the Cambrian has still not been found in Caernarvonshire, and the stratigraphical evidence for the Precambrian age of the Anglesey rocks (by perceived unconformity with known Cambrian strata) remains incomplete. The study reveals the great difficulty experienced by early geologists when working in unfossiliferous rocks, the evidence from included fragments proving particularly uncertain. The paper also examines further the community of nineteenth-century British geologists, with their various factions and competing interests.     

The archaean controversy in britain: Part IV—Some general theoretical and social issues

The main theoretical issues in the study of the history of the Archaean Controversy in Britain, which arose in the first three papers of the present series, are summarized and discussed—in particular the problem of stratigraphical work in rocks where no fossils can be discerned. The ‘Archaean’ geologists showed some leanings towards Neo-Neptunism and this, together with the fact that their work challenged the Murchison/Survey view of British geology, was one of the reasons for the controversy. At a deeper level, however, the question concerned the doctrine of uniformitarianism: Were metamorphic rocks to be found at any part of the stratigraphical column, or were they confined to the earliest period of the Earth's history? The establishment of the concept of Precambrian rocks and a suitable stratotype boundary is essentially a social question that has to be determined within the geological community. Some of the social processes whereby these matters are decided internationally are considered, and it is noted that the best location of the ‘Golden Spike’ for the Precambrian/Cambrian boundary has only just been settled (by vote). The paper also explores some nineteenth-century ideas about the nature of metamorphism, and the early conditions of the world.     

The Archaean controversy in Britain: Part II—The Malverns and Shropshire

An account is given of early geological researches in the Malverns, the Church Stretton area, and the Wrekin. The reconnaissance work of Murchison suggested that each of these areas had Silurian sediments, intruded by igneous rocks (called trap or syenite). The early Survey maps were compiled on this theoretical basis, with the result that the Silurian sediments were regarded as the oldest rocks in Shropshire and the Malverns. Local geologists, working in the three areas, and with sufficient time to study the exposures in detail, began to develop the idea of ‘islands’ of Precambrian (Archaean) rock (perhaps showing some stratification), having younger sediments deposited thereon. This Archaean model was taken up and actively developed, and the stratigraphical details worked out, with the island model being gradually modified. Debates were stronger between members of the ‘Archaean’ fraternity than with the Survey. Traces of trilobite remains were found by Callaway at Comley, near Caer Caradoc, and were identified by Lapworth as Olenellus, enabling the underlying Wrekin Quartzite to be established as the base of the Cambrian, in agreement with ideas developed in North America and Scandinavia. Arguments are detailed concerning the relative ages of the ‘Uriconian’ and ‘Longmyndian’ rocks, and their constituent units. Both were agreed to be Precambrian, but the evidence in terms of field mapping, in relation to the Wrekin Quartzite, is not complete. The problems of stratigraphical work in unfossiliferous rocks are displayed, and also the efforts to achieve correlations with areas such as Pembrokeshire and Anglesey are described. Though consensus has been reached on the Precambrian status of the Malvernian, Uriconian and Longmyndian rocks, radiometric age determinations and other evidence throw doubt on some aspects of the consensus, and research continues.     

James geikie,james croll,and the eventful ice age

James Geikie's Great Ice Age (1874) first presented to the geological public the Pleistocene. modern interpretation of alternating mild and cold periods during the Though it was supported by geological evidence, Geikie's view of the Ice Age was based on a theoretical framework supplied by the climatic physics of James Croll. Mid-nineteenth-century British geologists had encountered great difficulty in making sense out of the varied and complicated glacial deposits, or ‘drift’, and had formulated the ‘iceberg’ theory to account for the apparent chaos of the drift, an explanation which discouraged its stratigraphic study. The reaffirmation of faith in continental glaciation by several Scottish geologists in the 1850s brought with it a belief in an eventful Pleistocene, but it remained difficult to discover the events of Ice Age history from study of the glacial deposits. In 1864 Croll presented a detailed climatic history of the Ice Age deduced from astronomy and physical geography. By 1871 James Geikie was using Croll's scheme of Ice Age history as the basis for his impressive synthesis of Pleistocene data from throughout the world.     

Stanisław Staszic: An Early Surveyor of the Geology of Central and Eastern Europe

In the late eighteenth and early nineteenth centuries the Polish geoscientist, philosopher, and statesman Stanis?aw Staszic (1755–1826) conducted an extensive geological survey of Poland and adjacent areas. In 1815, he completed a book (in Polish), On the geology of the Carpathians and other mountains and lowlands of Poland, complemented by a well-made geological map of Central and Eastern Europe. Early in the nineteenth century, Staszic refined the idea of ‘geological mapping’, though initially he was interested in the exploration of mineral deposits, rock salt, copper and iron ores, and coal. Unlike his predecessors, his book adopted a temporal subdivision of rocks, using a somewhat modified version of Abraham Gottlob Werner's system. He delineated the surface distribution of five rock units and coloured them onto his map. His work gave expression to his view of geological history, and brought the ‘Enlightenment Period’ of geology in Central and Eastern Europe to a close.     

Essay Review: Looking for the Rhetoric of Science

The characteristics of inductivist historiography of science, as practised by earlier scientist/historians, and Whig historiography, as practised by earlier political historians, are described, according to the accounts of Agassi and Butterfield. It is suggested that the writings of Geikie on the history of geology allow us to characterize him as a Whig/inductivist historian of science who formulated anachronistic judgements. It is further suggested that his writings have had a considerable long-term effect on interpretations of the history of geology. The character of Geikie's historiography is related to his social, political and religious views, his historicism, and his romantic enthusiasm for Nature. His methodological pronouncements are examined: he believed that the present is the key to the past, and also that the past is the key to the present. He was an empiricist and inductivist. These epistemological and methodological views impinged on his historiography of science. If one attempts to criticize Geikie's historiography, though one may try to judge his work according to the norms of his own day and age, historical anachronism cannot be avoided entirely and one may oneself be charged with acting ‘Whiggishly’. Historians of science, in the process of professionalization, have accepted the historiographical norms of general historians (perhaps for socio-economic reasons), but in so doing have inherited a problem that arises whenever they contemplate earlier historical writings. It is suggested that there may be more room for Whiggish historiography of science than is presently deemed acceptable. Alternatively, one may wish to draw a careful distinction between science and its meta-discipline, the historiography of science. Whig historiography conflates the two, and the work of Geikie (a scientist/historian par excellence) provides a good illustration of this.     

Autobiography and ‘The Two Cultures’ in the novels of C. P. Snow

That C. P. Snow had first-hand experience both in science and writing was taken for granted in the years of controversy over ‘the two cultures’, but neither the quality of his experience nor the circumstances of his eventual adoption of a literary career was given close enough consideration. Snow's own statements on these two points are often misleading. Yet the autobiographical nature of his fiction throws significant light on the subject. An examination of the autobiographical elements in Snow's novels in the light of his conception of the novel raises the question of whether his shift from science to literature was exactly the result of a genuine choice and also reveals that the two cultures dichotomy is embedded in his personal experience.     

De-anthropomorphizing energy and energy conservation: The case of Max Planck and Ernst Mach

Discussions on the relation between Mach and Planck usually focus on their famous controversy, a conflict between ‘instrumentalist’ and realist philosophies of science that revolved around the specific issue of the existence of atoms. This article approaches their relation from a different perspective, comparing their analyses of energy and energy conservation. It is argued that this reveals a number of striking similarities and differences. Both Mach and Planck agreed that the law was valid, and they sought to purge energy of its anthropomorphic elements. They did so in radically different ways, however, illustrating the differences between Mach's ‘historical’ and Planck's ‘rationalistic’ accounts of knowledge. Planck's attempt to de-anthropomorphize energy was part of his attempt to demarcate theoretical physics from other disciplines. Mach's attempt to de-anthropomorphize energy is placed in the context of fin-de-siècle Vienna. By doing so, this article also proposes a new interpretation of Mach as a philosopher, historian and sociologist of science.     

The Replication of Hertz's Cathode Ray Experiments

I reappraise in detail Hertz's cathode ray experiments. I show that, contrary to Buchwald's (1995) evaluation, the core experiment establishing the electrostatic properties of the rays was successfully replicated by Perrin (probably) and Thomson (certainly). Buchwald's discussion of ‘current purification’ is shown to be a red herring. My investigation of the origin of Buchwald's misinterpretation of this episode reveals that he was led astray by a focus on what Hertz ‘could do’—his experimental resources. I argue that one should focus instead on what Hertz wanted to achieve—his experimental goals. Focusing on these goals, I find that his explicit and implicit requirements for a successful investigation of the rays’ properties are met by Perrin and Thomson. Thus, even by Hertz's standards, they did indeed replicate his experiment.     

David Hume's no-miracles argument begets a valid No-Miracles Argument

Hume's essay ‘Of Miracles’ has been a focus of controversy ever since its publication. The challenge to Christian orthodoxy was only too evident, but the balance-of-probabilities criterion advanced by Hume for determining when testimony justifies belief in miracles has also been a subject of contention among philosophers. The temptation for those familiar with Bayesian methodology to show that Hume's criterion determines a corresponding balance-of-posterior probabilities in favour of miracles is understandable, but I will argue that their attempts fail. However, I show that his criterion generates a valid form of the so-called No-Miracles Argument appealed to by modern realist philosophers, whose own presentation of it, despite their possession of the probabilistic machinery Hume himself lacked, is invalid.     

Rediscovering Einstein's legacy: How Einstein anticipates Kuhn and Feyerabend on the nature of science

Thomas Kuhn and Paul Feyerabend promote incommensurability as a central component of their conflicting accounts of the nature of science. This paper argues that in so doing, they both develop Albert Einstein's views, albeit in different directions. Einstein describes scientific revolutions as conceptual replacements, not mere revisions, endorsing ‘Kant-on-wheels’ metaphysics in light of ‘world change’. Einstein emphasizes underdetermination of theory by evidence, rational disagreement in theory choice, and the non-neutrality of empirical evidence. Einstein even uses the term ‘incommensurable’ specifically to apply to challenges posed to comparatively evaluating scientific theories in 1949, more than a decade before Kuhn and Feyerabend. This analysis shows how Einstein anticipates substantial components of Kuhn and Feyerabend's views, and suggests that there are strong reasons to suspect that Kuhn and Feyerabend were directly inspired by Einstein's use of the term ‘incommensurable’, as well as his more general methodological and philosophical reflections.     

Science and the romantic movement

Several authors have used the expression ‘formal asymmetry’ to characterize Einstein's method of introducing conceptual innovations. Prior to his use of formal asymmetries, however, Einstein relied upon analogy to introduce his major concepts, but without satisfactory results. He gradually refined another technique, reflection upon empirical problems, into the method of formal asymmetries, with impressive results. This historical study, based upon a textual analysis of Einstein's publications, raises a series of questions regarding the place of formal asymmetries in his work.     

On Kepler's awareness of the problem of experimental error

This paper is an account of Kepler's explicit awareness of the problem of experimental error. As a study of the Astronomia nova shows, Kepler exploited his awareness of the occurrences of experimental errors to guide him to the right conclusion. Errors were thus employed, so to speak, perhaps for the first time, to bring about a major physical discovery: Kepler's laws of planetary motion. ‘Know then’, to use Kepler's own words, ‘that errors show us the way to truth.’ With a survey of Kepler's revolutionary contribution to optics, the paper demonstrates that Kepler's awareness of the problem of experimental error extended beyond discrepancies between calculations and observations to types of error which pertain to observations and instruments. It emerges that Kepler's belief in the unity of knowledge and physical realism, facilitated—indeed created—the right philosophical posture for comprehending the problem of error in an entirely novel way.     

Jean-François Pilˆatre de Rozier

A translation of Kant's early paper, ‘Die Frage, ob die Erde veralte, physikalisch erwogen’ (‘The question, whether the Earth is ageing, considered physically’) is presented, and the main features of his position on this question in 1754 are summarized. In that year, Kant believed that the Earth was ageing, and that it was about 6000 years old. The paper allows us to understand the approximate outline of Kant's general ‘theory of the Earth’, and the relation of this theory to the cosmogony that he propounded in 1755. His ideas on the processes of erosion, and the formation of rivers, deltas and sandbanks, are noteworthy, and provide a contribution to the eighteenth-century literature on the denudation dilemma. Kant's general theory of erosion and deposition was, it seems, based to a significant extent on his knowledge of the geographical features of the Königsberg district. The general teleological position underpinning his philosophy may be discerned in this early paper, and he may be thought of as having been trying to orientate himself in space and time, so to speak, before undertaking his major reconstructions in philosophy.     

‘Soup’ vs. ‘Sparks’: Alexander Forbes and the Synaptic Transmission Controversy

During the twentieth century, a controversy raged over the role of electrical forces and chemical substances in synaptic transmission. Although the story of the ‘main’ participants is well documented, the story of ‘lesser’ known participants is seldom told. For example, Alexander Forbes, who was a prominent member of the axonologists, played an active role in the controversy and yet is seldom mentioned in standard accounts of the controversy. During the 1930s, Forbes incorporated chemical substances into his theory of synaptic transmission, advocating a complementarity model for the role of electrical forces and chemical substances. By focusing on Forbes and the axonologists, the controversy is simply more than a debate over ‘soup’ vs. ‘sparks’ but also involves the relative roles of electrical forces and chemical substances in synaptic transmission. The implications of this case study for the nature of scientific controversies are also discussed.     

A beautiful sea: P. A. M. Dirac's epistemology and ontology of the vacuum

This paper charts P.A.M. Dirac's development of his theory of the electron, and its radical picture of empty space as an almost-full plenum. Dirac's Quantum Electrodynamics famously accomplished more than the unification of special relativity and quantum mechanics. It also accounted for the ‘duplexity phenomena’ of spectral line splitting that we now attribute to electron spin. But the extra mathematical terms that allowed for spin were not alone, and this paper charts Dirac's struggle to ignore or account for them as a sea of strange, negative-energy, particles with positive ‘holes’. This work was not done in solitude, but rather in exchanges with Dirac's correspondence network. This social context for Dirac’s work contests his image as a lone genius, and documents a community wrestling with the ontological consequences of their work. Unification, consistency, causality, and community are common factors in explanations in the history of physics. This paper argues on the basis of materials in Dirac's archive that --- in addition --- mathematical beauty was an epistemological factor in the development of the electron and hole theory. In fact, if we believe that Dirac's beautiful mathematics captures something of the world, then there is both an epistemology and an ontology of mathematical beauty.