Inventing Temperature Read online

  4.

  Theory, Measurement, and Absolute Temperature 159

  Narrative: The Quest for the Theoretical Meaning of Temperature 159

  Temperature, Heat, and Cold 160

  Theoretical Temperature before Thermodynamics 168

  William Thomson's Move to the Abstract 173

  Thomson's Second Absolute Temperature 182

  Semi-Concrete Models of the Carnot Cycle 186

  Using Gas Thermometers to Approximate Absolute Temperature 192

  Analysis: Operationalization—Making Contact between Thinking and Doing 197

  The Hidden Difficulties of Reduction 197

  Dealing with Abstractions 202

  Operationalization and Its Validity 205

  Accuracy through Iteration 212

  Theoretical Temperature without Thermodynamics? 217

  5.

  Measurement, Justification, and Scientific Progress 220

  Measurement, Circularity, and Coherentism 221

  Making Coherentism Progressive: Epistemic Iteration 224

  Fruits of Iteration: Enrichment and Self-Correction 228

  Tradition, Progress, and Pluralism 231

  The Abstract and the Concrete 233

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  6.

  Complementary Science—History and Philosophy of Science as a Continuation of Science by Other Means 235

  The Complementary Function of History and Philosophy of Science 236

  Philosophy, History, and Their Interaction in Complementary Science 238

  The Character of Knowledge Generated by Complementary Science 240

  Relations to Other Modes of Historical and Philosophical Study of Science 247

  A Continuation of Science by Other Means 249

  Glossary of Scientific, Historical, and Philosophical Terms 251

  Bibliography 259

  Index 275

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  Note on Translation

  Where there are existing English translations of non-English texts, I have relied on them in quotations except as indicated. In other cases, translations are my own.

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  Chronology

  c. 1600 Galileo, Sanctorio, Drebbel, etc.: first recorded use of thermometers

  c. 1690 Eschinardi, Renaldini, etc.: first use of the boiling and melting points as fixed points of thermometry

  1710s Fahrenheit: mercury thermometer

  1733 First Russian expedition across Siberia begins, led by Gmelin

  c. 1740 Celsius: centigrade thermometer

  1751- Diderot et al.: L'Encyclopédie

  1760 Accession of George III in England.

  1764- Black: measurements of latent and specific heats

  Watt: improvements on the steam engine

  1770s Irvine: theory of heat capacity

  1772 De Luc: Recherches sur les modifications de l'atmosphère

  1776 Declaration of American Independence

  1777 Report of the Royal Society committee on thermometry

  1782-83 Compound nature of water argued; spread of Lavoisier's ideas

  1782 Wedgwood: clay pyrometer

  1783 Cavendish/Hutchins: confirmation of the freezing point of mercury

  1789 Lavoisier: Traité élémentaire de chimie

  Onset of the French Revolution.

  1793 Execution of Louis XVI

  Beginning of the "Terror" in France and war with Great Britain

  1794 Execution of Lavoisier; death of Robespierre, end of the Terror

  Establishment of the École Polytechnique in Paris

  1798 Laplace: first volume of Traité de mécanique céleste

  1799 Rise of Napoleon as First Consul

  1800 Rumford: founding of the Royal Institution

  Herschel: observation of infrared heating effects

  Volta: invention of the "pile" (battery)

  Nicholson and Carlisle: electrolysis of water

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  1801 Berthollet/Proust: beginning of controversy on chemical proportions

  1802 Dalton; Gay-Lussac: works on the thermal expansion of gases

  1807 Davy: isolation of potassium and sodium

  1808 Dalton: first part of A New System of Chemical Philosophy

  1815 Fall of Napoleon

  c. 1820 Fresnel: establishment of the wave theory of light

  1820 Oersted: discovery of electromagnetic action

  1824 Carnot: Réflexions sur la puissance motrice du feu

  1827 Death of Laplace

  1831 Faraday: discovery of electromagnetic induction

  1837 Pouillet: reliable low-temperature measurements down to −80°C

  1840s Joule, Mayer, Helmholtz, etc.: conservation of energy

  1847 Regnault: first extensive set of thermal measurements published

  1848 William Thomson (Lord Kelvin): first definition of absolute temperature

  1854 Joule and Thomson: operationalization of Thomson's second absolute temperature, by means of the porous-plug experiment

  1871 End of Franco-Prussian War; destruction of Regnault's laboratory

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  Inventing Temperature

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  Introduction

  This book aspires to be a showcase of what I call "complementary science," which contributes to scientific knowledge through historical and philosophical investigations. Complementary science asks scientific questions that are excluded from current specialist science. It begins by re-examining the obvious, by asking why we accept the basic truths of science that have become educated common sense. Because many things are protected from questioning and criticism in specialist science, its demonstrated effectiveness is also unavoidably accompanied by a degree of dogmatism and a narrowness of focus that can actually result in a loss of knowledge. History and philosophy of science in its "complementary" mode can ameliorate this situation, as I hope the following chapters will illustrate in concrete detail.

  Today even the most severe critics of science actually take a lot of scientific knowledge for granted. Many results of science that we readily believe are in fact quite extraordinary claims. Take a moment to reflect on how unbelievable the following propositions would have appeared to a keen and intelligent observer of nature from 500 years ago. The earth is very old, well over 4 billion years of age; it exists in a near-vacuum and revolves around the sun, which is about 150 million kilometers away; in the sun a great deal of energy is produced by nuclear fusion, the same kind of process as the explosion of a hydrogen bomb; all material objects are made up of invisible molecules and atoms, which are in turn made up of elementary particles, all far too small ever to be seen or felt directly; in each cell of a living creature there is a hypercomplex molecule called DNA, which largely determines the shape and functioning of the organism; and so on. Most members of today's educated public subscribing to the "Western" civilization would assent to most of these propositions without hesitation, teach them confidently to their children, and become indignant when some ignorant people question these truths. However, if they were asked to say why they believe these items of scientific common sense, most would be unable to produce any convincing arguments. It may even be that the more basic and firm the belief is, the more stumped we tend to feel in trying to

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  justify it. Such a correlation would indicate that unquestioning belief has served as a substitute for genuine understanding.

  Nowhere is this situation more striking than in our scientific knowledge of heat, which is why it is an appropriate subject matter of this study. Instead of revisiting debates about the metaphysical nature of heat, which are very well known to historians of science, I will investigate some basic difficulties in an area that is usually considered much less problematic, and at the same time fundamental to all empirical studies of heat. That area of study is thermometry, the measurement of temperature. How do we know that our thermo
meters tell us the temperature correctly, especially when they disagree with each other? How can we test whether the fluid in our thermometer expands regularly with increasing temperature, without a circular reliance on the temperature readings provided by the thermometer itself? How did people without thermometers learn that water boiled or ice melted always at the same temperature, so that those phenomena could be used as "fixed points" for calibrating thermometers? In the extremes of hot and cold where all known thermometers broke down materially, how were new standards of temperature established and verified? And were there any reliable theories to support the thermometric practices, and if so, how was it possible to test those theories empirically, in the absence of thermometry that was already well established?

  These questions form the topics of the first four chapters of this book, where they will be addressed in full detail, both historically and philosophically. I concentrate on developments in the eighteenth and nineteenth centuries, when scientists established the forms of thermometry familiar today in everyday life, basic experimental science, and standard technological applications. Therefore I will be discussing quite simple instruments throughout, but simple epistemic questions about these simple instruments quickly lead us to some extremely complex issues. I will show how a whole host of eminent past scientists grappled with these issues and critically examine the solutions they produced.

  I aim to show that many simple items of knowledge that we take for granted are in fact spectacular achievements, obtained only after a great deal of innovative thinking, painstaking experiments, bold conjectures, and serious controversies, which may in fact never have been resolved quite satisfactorily. I will point out deep philosophical questions and serious technical challenges lurking behind very elementary results. I will bring back to life the loving labors of the great minds who created and debated these results. I will attempt to communicate my humble appreciation for these achievements, while sweeping away the blind faith in them that is merely a result of schoolroom and media indoctrination.

  It is neither desirable nor any longer effective to try bullying people into accepting the authority of science. Instead, all members of the educated public can be invited to participate in science, in order to experience the true nature and value of scientific inquiry. This does not mean listening to professional scientists tell condescending stories about how they have discovered wonderful things, which you should believe for reasons that are too difficult for you to understand in real depth and detail. Doing science ought to mean asking your own questions, making your own investigations, and drawing your own conclusions for your own reasons. Of course it will not be feasible to advance the "cutting edge" or "frontier" of

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  modern science without first acquiring years of specialist training. However, the cutting edge is not all there is to science, nor is it necessarily the most valuable part of science. Questions that have been answered are still worth asking again, so you can understand for yourself how to arrive at the standard answers, and possibly discover new answers or recover forgotten answers that are valuable.

  In a way, I am calling for a revival of an old style of science, the kind of "natural philosophy" that was practiced by the European "gentlemen" of the eighteenth and nineteenth centuries with such seriousness and delight. But the situation in our time is indeed different. On the encouraging side, today a much larger number of women and men can afford to engage in activities that are not strictly necessary for their immediate survival. On the other hand, science has become so much more advanced, professionalized, and specialized in the last two centuries that it is no longer very plausible for the amateurs to interact with the professionals on an equal footing and contribute in an immediate sense to the advancement of specialist knowledge.

  In this modern circumstance, science for the non-specialist and by the non-specialist should be historical and philosophical. It is best practiced as "complementary science" (or the complementary mode of history and philosophy of science), as I explain in detail in chapter 6. The studies contained in the first four chapters are presented as illustrations. They are offered as exemplars that may be followed in pursuing other studies in complementary science. I hope that they will convince you that complementary science can improve our knowledge of nature. Most of the scientific material presented there is historical, so I am not claiming to have produced much that is strictly new. However, I believe that the rehabilitation of discarded or forgotten knowledge does constitute a form of knowledge creation. Knowing the historical circumstances will also set us free to agree or disagree with the best judgments reached by the past masters, which form the basis of our modern consensus.

  Each of the first four chapters takes an item of scientific knowledge regarding temperature that is taken for granted now. Closer study, however, reveals a deep puzzle that makes it appear that it would actually be quite impossible to obtain and secure the item of knowledge that seemed so straightforward at first glance. A historical look reveals an actual scientific controversy that took place, whose vicissitudes are followed in some detail. The conclusion of each episode takes the form of a judgment regarding the cogency of the answers proposed and debated by the past scientists, a judgment reached by my own independent reflections—sometimes in agreement with the verdict of modern science, sometimes not quite.

  Each of those chapters consists of two parts. The narrative part states the philosophical puzzle and gives a problem-centered narrative about the historical attempts to solve that puzzle. The analysis part contains various in-depth analyses of certain scientific, historical, and philosophical aspects of the story that would have distracted the flow of the main narrative given in the first part. The analysis part of each chapter will tend to contain more philosophical analyses and arguments than the narrative, but I must stress that the division is not meant to be a separation of history and philosophy. It is not the case that philosophical ideas and

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  arguments cannot be embodied in a narrative, and it is also not the case that history should always be presented in a narrative form.

  The last parts of the book are more abstract and methodological. Chapter 5 presents in a more systematic and explicit manner a set of abstract epistemological ideas that were embedded in the concrete studies in the first four chapters. In that discussion I identify measurement as a locus where the problems of foundationalism are revealed with stark clarity. The alternative I propose is a brand of coherentism buttressed by the method of "epistemic iteration." In epistemic iteration we start by adopting an existing system of knowledge, with some respect for it but without any firm assurance that it is correct; on the basis of that initially affirmed system we launch inquiries that result in the refinement and even correction of the original system. It is this self-correcting progress that justifies (retrospectively) successful courses of development in science, not any assurance by reference to some indubitable foundation. Finally, in chapter 6, I close with a manifesto that articulates in explicit methodological terms what it is that I am trying to achieve with the kind of studies that are included in this book. The notion of complementary science, which I have sketched only very briefly for now, will be developed more fully and systematically there.

  As this book incorporates diverse elements, it could be read selectively. The main themes can be gathered by reading the narrative parts of the first four chapters; in that case, various sections in the analysis parts of those chapters can be sampled according to your particular interests. If you have little patience for historical details, it may work to read just the analysis parts of chapters 1 to 4 (skipping the obviously historical sections), then chapter 5. If you are simply too busy and also prefer to take philosophy in the more abstract vein, then chapter 5 could be read by itself; however, the arguments there will be much less vivid and convincing unless you have seen at least some of the details in earlier chapters. Chapter 6 is intended mainly for professional scholars and advanced students in the history an
d philosophy of science. However, for anyone particularly excited, puzzled, or disturbed by the work contained in the first five chapters, it will be helpful to read chapter 6 to get my own explanation of what I am trying to do. In general, the chapters could be read independently of each other and in any order. However, they are arranged in roughly chronological order and both the historical and the philosophical discussions contained in them do accumulate in a real sense, so if you have the time and intention to read all of the chapters, you would do well to read them in the order presented.