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History And Philosophy Of Physics

"Sufficiently Advanced Technology" for Gravitational Wave Detection

The science fiction writer Arthur C. Clarke wrote, "Any sufficiently advanced technology is indistinguishable from magic." While not magical by any means, the technology used to detect gravitational waves starting in 2015 is surely sufficiently advanced to be remarkable by any ordinary standard. That technology was developed over a period of almost six decades; the people who were directly involved numbered in the thousands. In this article, I give an idiosyncratic account of the history, with a focus on the question of how people learned what measurement technology would be "sufficiently advanced" to succeed in detecting gravitational waves.

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History And Philosophy Of Physics

100 years of the first experimental test of General Relativity

Einsteins general theory of relativity is one of the most important accomplishments in the history of science. Its experimental verification a century ago is therefore an essential milestone that is worth celebrating in full. We reassess the importance of one of the two expeditions that made these measurements possible, a story that involves a sense of adventure and scientific ingenuity in equal measure.

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History And Philosophy Of Physics

A (not so) brief history of lunar distances: Lunar longitude determination at sea before the chronometer

Longitude determination at sea gained increasing commercial importance in the late Middle Ages, spawned by a commensurate increase in long-distance merchant shipping activity. Prior to the successful development of an accurate marine timepiece in the late-eighteenth century, marine navigators relied predominantly on the Moon for their time and longitude determinations. Lunar eclipses had been used for relative position determinations since Antiquity, but their rare occurrences precludes their routine use as reliable way markers. Measuring lunar distances, using the projected positions on the sky of the Moon and bright reference objects--the Sun or one or more bright stars--became the method of choice. It gained in profile and importance through the British Board of Longitude's endorsement in 1765 of the establishment of a Nautical Almanac. Numerous 'projectors' jumped onto the bandwagon, leading to a proliferation of lunar ephemeris tables. Chronometers became both more affordable and more commonplace by the mid-nineteenth century, signaling the beginning of the end for the lunar distance method as a means to determine one's longitude at sea.

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History And Philosophy Of Physics

A Case Study of a Scientific Blunder. History and Philosophical Teachings

In 1988, in cooperation with a team of experimental physicists, a Condensed Matter theorist, X, published in Physical Review Letters a crucial experimental result dealing with a revolutionary new theory. The conclusions of the paper were proved incorrect a few months later. I discuss the various factors -- scientific, instrumental, but also psychological, sociological ones -- which led to this blunder. I believe this story sheds some light on the process of scientific discovery, explanation, falsification, confirmation, and errors.

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History And Philosophy Of Physics

A Changing Dichotomy: The Conception of the "Macroscopic" and "Microscopic" Worlds in the History of Physics

This short essay traces the conceptual history of micro- and macroscopicity in the context of physical science. By focusing on three distinct episodes spanning five centuries, we show the scientific and philosophical meanings of this antonym pair, despite never being far from "the small" and "the large," have been evolving as the frontier of science advances. We analyze the intellectual and material impetus for these movements, and conclude that this conceptual history reflects the changing interaction between the natural world and humankind.

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History And Philosophy Of Physics

A Man Misunderstood: Von Neumann did not claim that his entropy corresponds to the phenomenological thermodynamic entropy

Recently, attention has returned to the now-famous 1932 thought experiment in which John von Neumann establishes the form of the quantum mechanical von Neumann entropy -Tr ρlnρ ( S VN ), supposedly by arguing for its correspondence with the phenomenological thermodynamic entropy ( S TD ). Hemmo and Shenker (2006) reconstruct von Neumann's thought experiment and argue that it fails to establish this desired correspondence. Prunkl (2019) and Chua (2019) challenge Hemmo and Shenker's result in turn. This paper aims to provide a new foundation for the current debate by revisiting the original text (von Neumann (1996, 2018)). A thorough exegesis of von Neumann's cyclical gas transformation is put forth, along with a reconstruction of two additional thought experiments from the text. This closer look reveals that von Neumann's goal is not to establish a link between S VN and S TD , as is assumed throughout the current debate, but rather to establish a correspondence between S VN and the Gibbs statistical mechanical entropy S G . On these grounds I argue that the existing literature misunderstands and misrepresents his goals. A revised understanding is required before the success of von Neumann's reversible gas transformation can be definitively granted or denied.

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History And Philosophy Of Physics

A Natural Introduction to Fine-Tuning

A well-known topic within the philosophy of physics is the problem of fine-tuning: the fact that the universal constants seem to take non-arbitrary values in order for live to thrive in our Universe. In this paper we will talk about this problem in general, giving some examples from physics. We will review some solutions like the design argument, logical probability, cosmological natural selection, etc. Moreover, we will also discuss why it's dangerous to uphold the Principle of Naturalness as a scientific principle. After going through this paper, the reader should have a general idea what this problem exactly entails whenever it is mentioned in other sources and we recommend the reader to think critically about these concepts.

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History And Philosophy Of Physics

A New Task for the Philosophy of Science

This paper argues that philosophers of science have before them an important new task that they urgently need to take up. It is to convince the scientific community to adopt and implement a new philosophy of science that does better justice to the deeply problematic basic intellectual aims of science than that which we have at present. Problematic aims evolve with evolving knowledge, that part of philosophy of science concerned with aims and methods thus becoming an integral part of science itself. The outcome of putting this new philosophy into scientific practice would be a new kind of science, both more intellectually rigorous and one that does better justice to the best interests of humanity.

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History And Philosophy Of Physics

A Personal History of the Hastings-Michalakis Proof of Hall Conductance Quantization

This is a personal history of the Hastings-Michalakis proof of quantum Hall conductance quantization.

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History And Philosophy Of Physics

A Precipice Below Which Lies Absurdity? Theories without a Spacetime and Scientific Understanding

While the relation between visualization and scientific understanding has been a topic of long-standing discussion, recent developments in physics have pushed the boundaries of this debate to new and still unexplored realms. For it is claimed that, in certain theories of quantum gravity, spacetime 'disappears': and this suggests that one may have sensible physical theories in which spacetime is completely absent. This makes the philosophical question whether such theories are intelligible, even more pressing. And if such theories are intelligible, the question then is how they manage to do so. In this paper, we adapt the contextual theory of scientific understanding, developed by one of us, to fit the novel challenges posed by physical theories without spacetime. We construe understanding as a matter of skill rather than just knowledge. The appeal is thus to understanding, rather than explanation, because we will be concerned with the tools that scientists have at their disposal for understanding these theories. Our central thesis is that such physical theories can provide scientific understanding, and that such understanding does not require spacetimes of any sort. Our argument consists of four consecutive steps: (a) We argue, from the general theory of scientific understanding, that although visualization is an oft-used tool for understanding, it is not a necessary condition for it; (b) we criticise certain metaphysical preconceptions which can stand in the way of recognising how intelligibility without spacetime can be had; (c) we catalogue tools for rendering theories without a spacetime intelligible; and (d) we give examples of cases in which understanding is attained without a spacetime, and explain what kind of understanding these examples provide.

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