Annual Progress Report
Mangling Geochronology: Agency, Contingency and Emergence in Kelvin's Debate(1)
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Short version based on APR (1) , April 2025.
- APR: Annual Progression Report
Introduction
On the 15th and 16th of June 1896 the University of Glasgow and City of Glasgow held a celebration of the academic and industrial achievements of William Thomson (then honoured as Lord Kelvin) over the previous fifty years. A world-renowned physicist, prosperous inventor and influential authority to governments and industry, Thomson was the preeminent scientific archetype of Victorian Britian. The honoured guests from around the world, including professors, politicians, dignitaries and diplomats, enjoyed ceremonies, banquets and dances held in Thomson’s honour.
News of events and attendees was reported globally in popular press and journals. Several articles reviewed Thomson’s life and work, from his abstract achievements in science, such as the formation of thermodynamics, to the concrete labours of laying of the transatlantic cable for which he was invested. Comprehensive summaries included Thomson’s contributions to the debate over the age of the Earth and often reported his role with the same conclusive and triumphant tones used in describing his theoretical and industrial work. One example read, “It were needless to review the controversy. Suffice it to say that the geologists have now considerably modified their periods”1 ; while another wrote, “Repeated attempts have been made to refute his results and the methods by which they have been arrived at, but to no purpose, and they are now generally accepted”2. In the contemporary popular press, Thomson’s word on the matter was as authoritative as the role of Science in Victorian society. Before the century was out this certainty would begin to dissolve and within a generation Thomson’s conclusions on the Earth’s antiquity would be overturned.
Episodes of scientific certainty, like the nineteenth century debate over the age of the Earth, demonstrate the traditional conflicts in analyses of science: one the one hand, science is a method of discovery, offering the paramount epistemic path to knowledge of the world; on the other, science is continually revisable and progresses through rejection of past convictions. In this case, Thomson’s work was compelling and yet disputed, his conclusions were definitive but eventually rejected. Late twentieth century developments in analyses of science3 try to avoid these contradictions by foregrounding scientific practice and participants to provide a narrative of historical events which is not biased by subsequent theoretical perspectives. This affords more accurate understanding of the scientific tradition, interested in the contemporary contexts and contestants, and consequently better informs comparisons in current disputes, where outcomes are not known a priori, and the dynamics of debate echo previous disagreements.
This research seeks to apply a recent analytical framework to the nineteenth century debate over the age of the Earth. Following several contributions in Pickering (2003) the format of this essay will begin with a historical narrative followed by analysis. First, the main events of the debate in the nineteenth century will be presented based on primary and secondary sources. This will be followed by an introduction to the analysis framework and an examination of events emphasising agency, contingency and emergence in the debate. Lastly, some remarks will look towards the development of a pedogeological tool based on the age of the Earth debate which will take the form of a historical game informed by the analytical insights.
Historical Perspective
A short story in chronological order.
Earth’s Antiquity in the Nineteenth Century
By the nineteenth century, geological accounts of the history of the Earth had moved away from Biblical exegesis. Calculations based on Christian texts and teachings, often quite sophisticated in their scholarship, estimated the Earth’s age to be of the order of thousands of years . However, disputes over the details of doctrine and interpretation led to schisms in a common understanding of how timescales should be extracted. Figure 1 illustrates such an exegetical account.
The New Science of the seventeenth and eighteenth centuries replaced divine intervention and teleological explanations with mechanical descriptions . Gradually the story of the Earth’s advent and development was deconvoluted from the story of the humanity. As part of the wider shift in epistemic tradition, geology evolved from the pastime of professors and parsons to an empirical discipline with professional practitioners, scholarly journals and an active amateur community .
Geological advances had been plentiful over the eighteenth century. Lithostratigraphic discoveries had brought a wealth of empirical data to digest. The grand conceptual triumph of this work was the Geological Column: layers of minerals and formations under topsoil interpreted as the products of previous geological processes. This led to an appreciation of geological history through the lithostratigraphic record called Deep Time, where the descending thickness or rock layers provided an ordering and relative durations of past ages. Together with an estimation of the rates of geological mechanisms, subterranean layers could provide chronometers to the history of the Earth.
In the nineteenth century, geologists did not claim to have extracted all the insights from the ground. The lithographic dataset was understood as far from complete. The oldest rocks formations came from industrial mines and prominent natural structures protruding from the Earth’s surface. New data arrived with each geological survey, which were competitively conducted by national organisations across the world as part of geopolitical contests. Even using the available data there was a lack of unanimity over its interpretation. Narrow disputes argued over the precise methods and rates of denudations and depositions. Wider debates concerned how to nest the Geological Column in the wider cosmological framework of a finite, infinite or cyclic universe. These limits and contests left the Geological concept of Deep Time without an agreed chronological anchor. Relative thickness and a cumulative depth could not be converted into a quantitative estimate of the number of years over which the Geological Column had accumulated.
Most Geologists in the nineteenth century accepted a Uniformitarian view of the Earth’s history but without a firm ontological framework, estimates of the age of the Earth were vast and varied. A rough consensus on rates of change built around a qualitative estimate of very to unquantifiably old, as was demonstrated in Hutton’s conclusion from 1788, “we find no vestige of a beginning, no prospect of an end” . When Lyell published The Principles of Geology (1830), Uniformitarianism and incalculable antiquity were canonised. Lyell offered large numbers as illustrations of the impressive timescale of geological processes, but precise or detailed calculations were not provided (or demanded by popular audience excited by Natural wonder and a professional community eager to do more than merely calculate). Darwin argued that evolutionary processes would similarly act indiscernibly slowly as a mechanism of biological development in of Origins of the Species (1859). He followed Lyell’s illustrated inexactitude in early editions and estimated the duration of the denudation of the Weald . The calculation became an infamous target for criticism soon after publication and subsequently removed from future editions , however the unintended effect was to precipitate an inter-disciplinary debate.
Kelvin’s Estimation of the Age of the Earth
The strongest attack against Darwin’s estimate was made by William Thomson (later Lord Kelvin) in his paper “On the Secular Cooling of the Earth” (1862) and was couched in a general criticism of the increasing and vague valuations of the age of the Earth. Thomson’s arguments focussed on the physical credibility of geological and evolutionary mechanisms. Clear physical errors in the proposed geological mechanisms (e.g. Lyell’s perpetual motions) were dispatched with strong refutations based on thermodynamics. Meanwhile, Thomson’s mathematical acumen gave him an ability to identify computational errors and quantify mechanisms in the detail of geological and evolutionary arguments. At the time his mathematical skills were unmatched in either geological or evolutional communities and the formal character of the reproachment left opponents struggling to defend their qualitative assumptions. This gave Thomson’s argument a burdensome weight for adversaries and revered gravitas for allies.
The most influential aspect of his attack was his own estimation of the age of the Earth. The basic strategy of the calculation was to use the formal apparatus of Thermodynamics, which he had helped devise, to calculate the period of (secular) cooling from the formation of the Earth to the current temperature, based on the conservation and dissipation of heat. Similar strategies had been suggested by Newton and empirically tested by Comte de Buffon; however, these early attempts lacked the mathematical rigour or empirical geological inputs.
To enable the calculation Thomson defined some limits and assumptions. First, the starting temperature from which the Earth cooled was defined. This was the point at which the molten Earth began to set and a crust formed (for life to grow from). Using some practical assumptions as to the composition of the Earth, a temperature could be estimated at which primordial rocks solidified. Next, after formation, the remaining heat energy of the Earth was dissipated from core to surface and out into space. This involved further postulation as to the Earth’s structure and the rate of heat conduction through the rigid body. The endpoint of the calculation is the present temperature to which the Earth has cooled since formation. Thomson’s believed his assumptions would provide the longest reasonable cooling period which he calculated to lie between 100 to 400 million years. He published his result in "The Secular Cooling of the Earth" 1862.
A parallel though related calculation (made earlier the same year) estimated the age of the Sun. This was based on calculating the time taken for the Sun to dissipate its energy as heat and light. The ingredients to this were two-fold. First, the initial energy of the Sun was quantified using the theory of Nebular collapse under gravity which described the formation of the solar system. This provided the initial stock of Solar energy converted to heat from gravity and concentrated in the star. The heat was then emitted over the life of the Sun. Second, the rate of the Sun’s energy output was estimated from the illumination of the Earth’s surface and scaled for uniform output in all directions. Together, the initial sum and rate of expenditure, provided a lifespan for the Sun, which Thomson calculated be around 100 million years. This gave a limitation to evolutionary accounts, as life without sunshine was inconceivable. The coincidence of the Solar and Earth lifetimes made the estimates mutually supporting and arguments became intwined.
Reactions and Compromises
The reaction of the geological or evolutionary communities was not welcoming as Thomson’s estimate was radically less than those based on the details of geological processes – mechanisms which were ignored in his estimate. Criticisms were made in print and public debates but in general, these reduced to reiterations of geological methods and measurements and fell short of the formal argument required to make significant ripostes. Contrastingly, the physics community was impressed with the thermodynamic principles and mathematical techniques of Thomson’s case, which was now seen as uniquely based on fundamental physical principles. Over the following months and years stratigraphical progress continued unaffected while geological chronologies began to conform to Thomson’s limits. Figure 2 shows a selection of Nineteenth century estimates after Thomson's 1862 paper.
Without a robust case to extend the limit from 100 million years geological and evolutionary theories were forced to make radical changes to quantitative descriptions of their subject. Either the rates of physical mechanisms (denudation, deposition and natural selection) had to speed up, or the principle of Uniformitarianism had to be dropped. Some geologists, such as Samual Haughton and Alfred Wallace, employed a strategy of modifying assumptions concerning denudation mechanisms and rates. With estimates adequately altered, calculations of the Earth’s age based on stratigraphical evidence could be squeezed into the envelope of ~100 million years.
A famous reply was Thomas Huxley’s address of 1869 where he made a defence of the theory of Evolution in light of the limitations from Thomson’s estimate of the Sun’s age. Huxley’s loud defence of Evolution quietly yielded to Thomson with the renouncement of the principle of Uniformity. Evolution in the past would have to be unlike the present if descriptions of biological development were to meet limit of 100 million years. Another notable response came from Croll (~1869) who aimed account for changes in evolutionary and geological processes within known physical mechanisms. Croll proposed ice ages could affect the rate of denudation and hence leave evidence in the stratigraphical record. He argued this evidence would correlate with periods of eccentricity in the Earth’s orbit, when the relatively greater distance from the sun would result in a global drop in temperature. Hence, if Astronomical methods could date ice ages from orbital calculations an alternative method of translating Deep Time to years could be found, which would confirm or refute Thomson’s calculation. In addition, ice ages could be argued to modify evolutionary rates, as animals would be concentrated in temperate regions and selective processes intensified with limiting resources.
Perry’s Proposal
Without a strong rebuttal of Thomson’s secular cooling argument or a coherent strategy of response, Thomson’s estimate became part of the paradigm of late nineteenth century geology – unwelcome but not unworkable. The Age of the Earth was after all only a corollary of the substantial work of geology. Geological process continued to be investigated, and the stratigraphical column constructed. At the end of the century, however, evolutionary debate once again upset the status quo which had prevailed. At the British Association for the Advancement of Science meeting in 1894 Robert Gascoyne-Cecil, Marquess of Salisbury presented an attack on Evolution including Thomson’s critique of older geological estimates and offered divine design as a superior explanation for human development. John Perry, a physicist (and onetime student of Thomson), was in the audience and took exception to the supernatural appeal as the sort of unscientific account that Thomson’s original objections had sought to purge. This inspired Perry to revisit Thomson’s calculations.
Perry showed, with the aid of some sophisticated and controversial mathematical techniques courtesy of Oliver Heaviside , that the original assumptions Thomson made to facilitate his calculation did not provide the maximum estimate of the age of the Earth. Of particular significance was Thomson’s model of a rigid Earth with heat dissipation by conduction alone. Perry demonstrated that reasonable alterations within the physical mechanisms that Thomson had described, could extend the limitations on secular cooling by hundreds of millions of years. These possibilities had gone unchecked due to the formal complexities in the original calculation. Perry believed that such wide variability meant Thomson should yield the weight of authority placed on his estimation and give more credence to geological estimates.
After some personal correspondence (including an ill-tempered Tait) a public debate played out in Nature over a few months in 1895 . The dispute soon went quiet without a declared winner; however, the repercussions were more significant. Observers sympathetic to Thomson believed his assumptions had been adequately defended and nothing need change. In fact, physicists had already argued that estimates maybe reduced to 10s of millions of years. On the other side, geologists and evolutionists saw formal criticism of Thomson, from within the ranks of physicists, as proof that compromise was possible. They celebrated that geological estimates could no longer be dismissed as physically impossible . However, regardless of any change in attitudes to the Earth’s estimated antiquity, Thomson’s model had become so ingrained in geological theory that there was no clear path or appetite for its elimination without mass revision.
The Decay of Kelvin’s Influence
The authority of Thomson’s calculation declined in the twentieth century as physicists began to understand radioactivity as a novel energy source which would upset existing models of secular cooling and solar output: hence the “storehouse of creation” was expanded. Almost immediately, the impact on age of the Earth calculations and Solar mechanisms were discussed . Thomson lived long enough to see the revolution begin, though the speculative and piecemeal estimates did not sway his official position. Instead, his authority would be eroded in stages over time.
To begin, it would take the first two of decades of the twentieth century before physicists could convince themselves, and then wary geologists, that radioactivity was indicative of age. The initial shock of transmutative decays had to be understood within a wider context of atomic theory and chemical isotopes. Only then could radioactive dating be adopted as the favoured indicator of antiquity and provide the independent measure Croll had sought. The age of the Earth ballooned into the billions of years, stretching the envelope of Deep Time further than geologists had imagined. Figure 3 shows Arthur Holme's estimates of the duration of Stratigraphical Periods based on radioacti
Even after the Earth’s antiquity was extended, the Solar age remained a problem as the radioactive processes of nuclear fission, soon ubiquitously demonstrated on Earth, could not be attributed to the Sun to extend its estimated output. It would take until the 1950s, when the superior energy output of nuclear fusion models was advanced, to extend the Sun’s lifetime . The radiation from Solar fusion could bathe the Earth for billions of years, granting an Evolutionary timescale to match the Earth’s antiquity.
The final hypothesis to be rejected regarded the Earth’s composition. By the end of 1960s Plate Tectonics supplanted rigid Earth theories. It was accepted that the Earth’s surface was not inflexible but sat atop a molten mantel with a liquid core. This meant heat dissipation would include convective mechanisms; a process which alone could have been used to extend estimations of the Earth’s age by hundreds of millions of years a century before, as Perry had argued . Figure 4 shows the modern Geological Column with a chronological timescale.
Framing the Dispute
With the historical account described some analysis of the nineteenth century debate can be made.
History of the Mangle
In 1995 Andrew Pickering published The Mangle of Practice: Time, Agency, and Science. In this work Pickering introduced a novel analytical framework which foregrounds the material tools, contexts and activities of scientific practice. The work is part of the wider meta-discipline of Science and Technology Studies (STS), which had over the previous decades provided critiques of science from various Social Science and Humanities perspectives. Where STS differed from the traditional analyses to be found inside Science or Philosophy was in foregrounding the practice of science rather than the content of theories. The focus changed from formal treatises to the work of researchers as they seek insights or attempt to manipulate parts of the world. In appreciating practice, STS criticises the customary accounts of scientific progress as whiggish and neglectful of contingency, using anachronisms from modern Scientific thought to ignore contemporary agency .
Pickering’s analysis followed Scientific agents: the day-to-day performers of scientific activity. Significantly (though not uniquely ), his descriptive language did not limit agency to humans. Conventionally, humans (if explicitly mentioned) are centres of activity and agency in descriptions of science. In The Mangle, agency can be found anywhere there is action, and scientific activity would quickly cease were it not for the responses of other agents. Non-human actors such as Nature, gadgets, analytical tools, academic communities all react to human doings. Scientific activity is described as iterations of moves and countermoves as attempts are made to accommodate the responses of agents which resist comprehension. Metaphors of interaction, such as the dialectic interaction of boardgames or the intertwined agency of dancers, are employed rather than one-sided imagery of conquest or dominance traditionally deployed. The analogy of the Mangle outlines the processes whereby the wrinkled and imperfect development of science and technology is flattened into a rational narrative.
Mangling History
The Mangle framework can be applied to the nineteenth century debate over the age of the Earth to follow trajectories of agency. Human interests are evident in the work of Lyell and Darwin as they sought to understand the processes of denudation and natural selection and hence estimate the age of the Earth and duration of life on Earth. In each case the initial estimations were resisted, not from within their respective disciplines (for example Catastrophists or Theists, respectively) but by an emergent interjection from beyond their disciplinary horizon. Thomson’s thermodynamic argument placed a limit on the Earth’s age and Sun’s duration of output. Neither Uniformitarian geologists nor Evolutionist biologists could match Thomson’s criticism with a formal reply. Instead, both camps accommodated the new temporal constraint: geologists increased the rates of denudation processes; while biologists looked for reasons to accelerate selective processes, including Croll’s work on orbits and ice ages.
Attempts to push back from within geology and biology against Thomson’s case failed as detractors could not continue the dance of agency without comparable formal ability. Even when Thomson’s assumptions were denounced, there was no subsequent step by which to continue the debate. The issue was not that Thomson simply denied requests to expand the limitation on the age of the Earth. Such analysis instils agency solely with Thomson which he could not wield by virtue of his word alone. Instead, agency was dispersed across several actors which would not acquiesce to the demands of geologists and evolutionists. The formal apparatus could not be contested: it was part of the great machinery of quantitative science. The assumptions, though criticised, were not refuted nor successfully supplanted: Nature did not grant convincing empirical evidence of more credible alternatives. And Thomson spoke with the disciplinary authority of physical science which was unimpeachable in nineteenth century academia and society. Hence, agency was not vested in a single human but across various actors.
Before the 1890s, the dance of agency lay dormant after accommodations had been made by geologists and evolutionists. The intermission may have continued longer had Perry not been inspired to act by the Marquess of Salisbury or had he not engaged with Heaviside. Perry resumed the dance by transforming the monolithic obstacle of the Thomson’s complex calculation into a new medium of accommodation using Heaviside’s simplifying notation . Thomson’s model was thus decomposed into separate assumptions which could be quantifiably and interrogated and participants could offer reasons for preferred postulates. Therefore, formalism became a collaborator to both sides rather than a partial protagonist for physicists alone.
Historical Gamification
Having made a brief analysis of the historical events the process of translation into a pedogeological tool can be considered.
Historical Game Studies and The Mangle
Historical Game Studies (HGS) is an artefact of this millennium, closely tied to Humanities, but it shares traits with STS such as a non-hegemonic focus, transdisciplinary interest and antagonisms. HGS foregrounds audience engagement with historical narratives and the consequences of this interaction . Aspects of gamification define and shape the margins of engagement. Game topics and themes are opportunities to invent, support or contest narratives. Characters and scenes provide voice and visibility to communities and events. As a critical discourse, HGS is not primarily concerned with the accuracy of historical narratives but rather the engagement with history.
A pedogeological tool is envisaged for the latter part of this research which will communicate the Manglish elements of the nineteenth century debate over the age of the Earth. Aspects of the game will be used to emphasise themes of agency, contingency and emergence. Without determining the game content or structure at this stage in the project there are several general opportunities available in which to embed themes. Players will have an active role in deciding the outcome of the game, e.g. selection of a goal in the game or choice of game path to obtain a goal. Agency will be held by a player as they react to resistances and devise accommodations to meet a goal. Agency will be passed to the game at points to progress towards an outcome. The rules of the game will manifest non-human agency which responds to player decisions and directs further moves, e.g. token location or point increments. Contingency can be presented in choices offered to players which change game paths or outcomes depending on player selection - iterations of game play should result in non-identical outcomes when player choices diverge. Emergence can be provided in the form of chance events which are not controlled by the players or determined by the game rules, e.g. shuffled cards or asynchronous interventions - iterations of game play should result in non-identical outcomes when emergent events vary. Finally, historical contingency can be foregrounded in a comparison of the game outcome with the historical record, e.g. success in obtaining the objective or time taken (translated from game moves) to reach the objective.
The pedogeological effect of the game will be assessed through audience engagement.
Summary
The nineteenth century debate over the age of the Earth between William Thomson and communities of contemporary geologists and evolutionary biologists presents an opportunity to apply Pickering’s Mangle framework in a historical setting. The value of this analysis lies in a description of scientific history as a dynamic and open-ended endeavour to comprehend the natural world despite unforeseen difficulties. Science is depicted as creative activity of participants rather than a mechanistic algorithm of theories and concepts.
The Mangle analysis can be further applied to enrich academic engagement with active themes communicated from historical analysis to a game audience. The themes of agency, contingency and emergence are synergistic with several aspects of gameplaying and provide inspiration for development of a pedogeological tool.
References and Footnotes
References by Theme
History
| Title | Author | Date | Publisher |
|---|---|---|---|
| The Age-of-the-Earth Debate | Badash L | 1989 | Scientific American, 90-96 |
| Lord Kelvin and the Age-of-the-Earth Debate | A Stinne | 2000 | Physics in Canada, 321-332 |
| Calculating the Age of the Earth and the Sun | A Stinner | 2002 | Physics Education 23(4), 296-305 |
| Lord Kelvin and the Age-of-the-Earth Debate: A Dramatization | A Stinner & J Teichmann | 2003 | Science & Education 12, 213-228 |
| Kelvin and the Age of the Earth | F M Richter | 1986 | Journal of Geology |
| John Perry’s neglected critique of Kelvin’s age for the Earth: A missed opportunity in geodynamics | England, Molnar, Richter | 2007 | GSA Today |
| Kelvin's age of the earth paradox revisited | F D Stacey | 2000 | Journal of Geophysical Research |
| 'Had Lord Kelvin a right?': John Perry, natural selection and the age of the Earth, 1894-1895 | B C Shipley | 2001 | The Geological Society of London |
| Oliver Heaviside, Fractional Operators, and the Age of the Earth | P J Nahin | 1985 | IEEE Transactions on Education |
| Kelvin and the Age of the Earth | Joe D Burchfield | 1990 | University of Chicago Press |
| Degrees Kelvin | David Lindley | 2004 | Aurum |
| The Chronologer's Quest | P W Jackson | 2018 | Cambridge University Press |
Science and Technology Studies
| Title | Author | Date | Publisher |
|---|---|---|---|
| The Mangle of Practice | Andrew Pickering | 1995 | University of Chicago Press |
| The Mangle in Practice | Ed. Andrew Pickering | 2003 | University of Chicago Press |
| The Scientific Revolution | Steven Shapin | 2018 | University of Chicago |
| Natural Order (chpt, 3,4,6) | Ed. B Barnes & S Shapin | 1979 | Sage Publications |
| How To Think About Science, episode 4 | CBC | 2015 | CBC: link |
Historical Game Studies
| Title | Author | Date | Publisher |
|---|---|---|---|
| Introduction: what is historical game studies? | A Chapman, A Foka & Jonathan Westin | 2017 | Rethinking History 21.3, 359-371 |
| Ten years of Historical Game Studies | S Caselli, KBR Giappone, TZ Majkowski | 2023 | Game |
| Playing with the Past (Introduction) | Ed. M Kapell and A B R Elliott | 2013 | Bloomsbury |
Footnotes
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North British Daily Mail 13/06/1896 ↩
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The Glasgow Herald 15/06/1896 ↩
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See examples from Pickering (1995), Latour (1986), Shapin & Schaffer (1989), etc. ↩
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Jackson (2018), Chpt. 2 ↩
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Shapin (2018), Chpt. 1 ↩
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As Porter puts it in Barnes & Shapin (1979): [The new discipline of geology] was lay, rather than clerical, comprising middle-class, professional men of science and gentlemen amateurs, rather than professional academics. It included men of all religious persuasions" ↩
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Uniformitarians understood geological developments to be slow and incremental, like existing phenomena; rather than punctuated with bursts of radical change (e.g. global floods or mass volcanism) as the Catastrophists had argued. ↩
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1788 version of Theory of the Earth ↩
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Darwin demonstrated the enormity of geological time by estimating how long geological processes would take to shape a relatively large and scenic part of the south English countryside. ↩
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Natural Selection proved controversial enough without providing additional non sequiturs to opponents. Thomson was not a supporter of Natural Selection, though publicly remained silent on much of the scientific detail. ↩
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William Thomson, along with his brother James, had been educated in advanced mathematical techniques from childhood by his father. Both would make use of their formal skills: James as a respected engineer and academic and William as the great natural philosopher. Both held positions at the University of Glasgow where their father had also taught. ↩
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Described in Jackson (2018), Chpt. 2 and Stinner (2002) ↩
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Reasonable assumptions (not significantly criticised) included: initial temperature of 3700ºC, temperature gradient of Earth's surface, Specific heat of Earth's crust, Thermal conduction coefficient of Earth's crust. ↩
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This theory of Solar genesis dated back to Kant and was developed by Helmholtz. ↩
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Stacey (2000) argues the age of the Earth estimate would have carried little weight had it had not been tied to the age of the Sun. ↩
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Thomson and Huxley did not debate in person but addressed their respective Geological audiences in . Glasgow and London. ↩
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Nahin (1985) argues Heaviside’s intervention broke the “chilling effect on debate” of Thomson’s “invulnerable mathematics” ↩
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Shipley (2001) summarises the publications. ↩
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Geikie voiced his frustrations that geologists had made many concessions to physicists without reciprocation (Shipley (2001)) ↩
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Thomson originally used this metaphor in his 1862 paper. ↩
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Examples in Badash (1989) ↩
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Holmes estimates in Jackson (2018), chpt. 13 ↩
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Fusion theories began ~1930 and were accepted in 1950s ↩
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England, Molnar, Richter (2007) laments this missed opportunity ↩
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Notable criticisms came from proponents of the Strong Program of Sociology of Science Knowledge, e.g. Bloor, Barnes and Henry (1996), Scientific knowledge: a sociological analysis ↩
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See the works of Latour and Callon on Actor-Network Theory ↩
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"It's an interesting word but it's not a great metaphor, I will concede that", Pickering (2015) in CBC interview 39:17. ↩
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The controversy of Heaviside’s symbolism itself provides new steps in the dance in disputes over the legitimacy of his method. ↩
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For a fuller introduction see Caselli, Giappone, Majkowski (2023) and A Chapman, A Foka & Jonathan Westin (2017) ↩