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Highly pathogenic avian influenza causes mass mortality in Sandwich Tern Thalasseus sandvicensis breeding colonies across north-western Europe
- Ulrich Knief, Thomas Bregnballe, Ibrahim Alfarwi, Mónika Z. Ballmann, Allix Brenninkmeijer, Szymon Bzoma, Antoine Chabrolle, Jannis Dimmlich, Elias Engel, Ruben Fijn, Kim Fischer, Bernd Hälterlein, Matthias Haupt, Veit Hennig, Christof Herrmann, Ronald in ‘t Veld, Elisabeth Kirchhoff, Mikael Kristersson, Susanne Kühn, Kjell Larsson, Rolf Larsson, Neil Lawton, Mardik Leopold, Sander Lilipaly, Leigh Lock, Régis Marty, Hans Matheve, Włodzimierz Meissner, Paul Morrison, Stephen Newton, Patrik Olofsson, Florian Packmor, Kjeld T. Pedersen, Chris Redfern, Francesco Scarton, Fred Schenk, Olivier Scher, Lorenzo Serra, Alexandre Sibille, Julian Smith, Wez Smith, Jacob Sterup, Eric Stienen, Viola Strassner, Roberto G. Valle, Rob S. A. van Bemmelen, Jan Veen, Muriel Vervaeke, Ewan Weston, Monika Wojcieszek, Wouter Courtens
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- Journal:
- Bird Conservation International / Volume 34 / 2024
- Published online by Cambridge University Press:
- 02 February 2024, e6
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In 2022, highly pathogenic avian influenza (HPAI) A(H5N1) virus clade 2.3.4.4b became enzootic and caused mass mortality in Sandwich Tern Thalasseus sandvicensis and other seabird species across north-western Europe. We present data on the characteristics of the spread of the virus between and within breeding colonies and the number of dead adult Sandwich Terns recorded at breeding sites throughout north-western Europe. Within two months of the first reported mortalities, 20,531 adult Sandwich Terns were found dead, which is >17% of the total north-western European breeding population. This is probably an under-representation of total mortality, as many carcasses are likely to have gone unnoticed and unreported. Within affected colonies, almost all chicks died. After the peak of the outbreak, in a colony established by late breeders, 25.7% of tested adults showed immunity to HPAI subtype H5. Removal of carcasses was associated with lower levels of mortality at affected colonies. More research on the sources and modes of transmission, incubation times, effective containment, and immunity is urgently needed to combat this major threat for colonial seabirds.
An isolated outbreak of diphtheria in South Africa, 2015 – Erratum
- S. Mahomed, M. Archary, P. Mutevedzi, Y. Mahabeer, P. Govender, G. Ntshoe, W. Kuhn, J. Thomas, A. Olowolagba, L. Blumberg, K. McCarthy, K. Mlisana, M. Du Plessis, A. Von Gottberg, P. Moodley
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- Journal:
- Epidemiology & Infection / Volume 146 / Issue 5 / April 2018
- Published online by Cambridge University Press:
- 03 July 2017, p. 664
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An isolated outbreak of diphtheria in South Africa, 2015
- S. MAHOMED, M. ARCHARY, P. MUTEVEDZI, Y. MAHABEER, P. GOVENDER, G. NTSHOE, W. KUHN, J. THOMAS, A. OLOWOLAGBA, L. BLUMBERG, K. MCCARTHY, K. MLISANA, M. DU PLESSIS, A. VON GOTTBERG, P. MOODLEY
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- Journal:
- Epidemiology & Infection / Volume 145 / Issue 10 / July 2017
- Published online by Cambridge University Press:
- 08 May 2017, pp. 2100-2108
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An outbreak of respiratory diphtheria occurred in two health districts in the province of KwaZulu-Natal in South Africa in 2015. A multidisciplinary outbreak response team was involved in the investigation and management of the outbreak. Fifteen cases of diphtheria were identified, with ages ranging from 4 to 41 years. Of the 12 cases that were under the age of 18 years, 9 (75%) were not fully immunized for diphtheria. The case fatality was 27%. Ninety-three household contacts, 981 school or work contacts and 595 healthcare worker contacts were identified and given prophylaxis against Corynebacterium diphtheriae infection. A targeted vaccination campaign for children aged 6–15 years was carried out at schools in the two districts. The outbreak highlighted the need to improve diphtheria vaccination coverage in the province and to investigate the feasibility of offering diphtheria vaccines to healthcare workers.
Contributors
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- By Mitchell Aboulafia, Frederick Adams, Marilyn McCord Adams, Robert M. Adams, Laird Addis, James W. Allard, David Allison, William P. Alston, Karl Ameriks, C. Anthony Anderson, David Leech Anderson, Lanier Anderson, Roger Ariew, David Armstrong, Denis G. Arnold, E. J. Ashworth, Margaret Atherton, Robin Attfield, Bruce Aune, Edward Wilson Averill, Jody Azzouni, Kent Bach, Andrew Bailey, Lynne Rudder Baker, Thomas R. Baldwin, Jon Barwise, George Bealer, William Bechtel, Lawrence C. Becker, Mark A. Bedau, Ernst Behler, José A. Benardete, Ermanno Bencivenga, Jan Berg, Michael Bergmann, Robert L. Bernasconi, Sven Bernecker, Bernard Berofsky, Rod Bertolet, Charles J. Beyer, Christian Beyer, Joseph Bien, Joseph Bien, Peg Birmingham, Ivan Boh, James Bohman, Daniel Bonevac, Laurence BonJour, William J. Bouwsma, Raymond D. Bradley, Myles Brand, Richard B. Brandt, Michael E. Bratman, Stephen E. Braude, Daniel Breazeale, Angela Breitenbach, Jason Bridges, David O. Brink, Gordon G. Brittan, Justin Broackes, Dan W. Brock, Aaron Bronfman, Jeffrey E. Brower, Bartosz Brozek, Anthony Brueckner, Jeffrey Bub, Lara Buchak, Otavio Bueno, Ann E. Bumpus, Robert W. Burch, John Burgess, Arthur W. Burks, Panayot Butchvarov, Robert E. Butts, Marina Bykova, Patrick Byrne, David Carr, Noël Carroll, Edward S. Casey, Victor Caston, Victor Caston, Albert Casullo, Robert L. Causey, Alan K. L. Chan, Ruth Chang, Deen K. Chatterjee, Andrew Chignell, Roderick M. Chisholm, Kelly J. Clark, E. J. Coffman, Robin Collins, Brian P. Copenhaver, John Corcoran, John Cottingham, Roger Crisp, Frederick J. Crosson, Antonio S. Cua, Phillip D. Cummins, Martin Curd, Adam Cureton, Andrew Cutrofello, Stephen Darwall, Paul Sheldon Davies, Wayne A. Davis, Timothy Joseph Day, Claudio de Almeida, Mario De Caro, Mario De Caro, John Deigh, C. F. Delaney, Daniel C. Dennett, Michael R. DePaul, Michael Detlefsen, Daniel Trent Devereux, Philip E. Devine, John M. Dillon, Martin C. Dillon, Robert DiSalle, Mary Domski, Alan Donagan, Paul Draper, Fred Dretske, Mircea Dumitru, Wilhelm Dupré, Gerald Dworkin, John Earman, Ellery Eells, Catherine Z. Elgin, Berent Enç, Ronald P. Endicott, Edward Erwin, John Etchemendy, C. Stephen Evans, Susan L. Feagin, Solomon Feferman, Richard Feldman, Arthur Fine, Maurice A. Finocchiaro, William FitzPatrick, Richard E. Flathman, Gvozden Flego, Richard Foley, Graeme Forbes, Rainer Forst, Malcolm R. Forster, Daniel Fouke, Patrick Francken, Samuel Freeman, Elizabeth Fricker, Miranda Fricker, Michael Friedman, Michael Fuerstein, Richard A. Fumerton, Alan Gabbey, Pieranna Garavaso, Daniel Garber, Jorge L. A. Garcia, Robert K. Garcia, Don Garrett, Philip Gasper, Gerald Gaus, Berys Gaut, Bernard Gert, Roger F. Gibson, Cody Gilmore, Carl Ginet, Alan H. Goldman, Alvin I. Goldman, Alfonso Gömez-Lobo, Lenn E. Goodman, Robert M. Gordon, Stefan Gosepath, Jorge J. E. Gracia, Daniel W. Graham, George A. Graham, Peter J. Graham, Richard E. Grandy, I. Grattan-Guinness, John Greco, Philip T. Grier, Nicholas Griffin, Nicholas Griffin, David A. Griffiths, Paul J. Griffiths, Stephen R. Grimm, Charles L. Griswold, Charles B. Guignon, Pete A. Y. Gunter, Dimitri Gutas, Gary Gutting, Paul Guyer, Kwame Gyekye, Oscar A. Haac, Raul Hakli, Raul Hakli, Michael Hallett, Edward C. Halper, Jean Hampton, R. James Hankinson, K. R. Hanley, Russell Hardin, Robert M. Harnish, William Harper, David Harrah, Kevin Hart, Ali Hasan, William Hasker, John Haugeland, Roger Hausheer, William Heald, Peter Heath, Richard Heck, John F. Heil, Vincent F. Hendricks, Stephen Hetherington, Francis Heylighen, Kathleen Marie Higgins, Risto Hilpinen, Harold T. Hodes, Joshua Hoffman, Alan Holland, Robert L. Holmes, Richard Holton, Brad W. Hooker, Terence E. Horgan, Tamara Horowitz, Paul Horwich, Vittorio Hösle, Paul Hoβfeld, Daniel Howard-Snyder, Frances Howard-Snyder, Anne Hudson, Deal W. Hudson, Carl A. Huffman, David L. Hull, Patricia Huntington, Thomas Hurka, Paul Hurley, Rosalind Hursthouse, Guillermo Hurtado, Ronald E. Hustwit, Sarah Hutton, Jonathan Jenkins Ichikawa, Harry A. Ide, David Ingram, Philip J. Ivanhoe, Alfred L. Ivry, Frank Jackson, Dale Jacquette, Joseph Jedwab, Richard Jeffrey, David Alan Johnson, Edward Johnson, Mark D. Jordan, Richard Joyce, Hwa Yol Jung, Robert Hillary Kane, Tomis Kapitan, Jacquelyn Ann K. Kegley, James A. Keller, Ralph Kennedy, Sergei Khoruzhii, Jaegwon Kim, Yersu Kim, Nathan L. King, Patricia Kitcher, Peter D. Klein, E. D. Klemke, Virginia Klenk, George L. Kline, Christian Klotz, Simo Knuuttila, Joseph J. Kockelmans, Konstantin Kolenda, Sebastian Tomasz Kołodziejczyk, Isaac Kramnick, Richard Kraut, Fred Kroon, Manfred Kuehn, Steven T. Kuhn, Henry E. Kyburg, John Lachs, Jennifer Lackey, Stephen E. Lahey, Andrea Lavazza, Thomas H. Leahey, Joo Heung Lee, Keith Lehrer, Dorothy Leland, Noah M. Lemos, Ernest LePore, Sarah-Jane Leslie, Isaac Levi, Andrew Levine, Alan E. Lewis, Daniel E. Little, Shu-hsien Liu, Shu-hsien Liu, Alan K. L. Chan, Brian Loar, Lawrence B. Lombard, John Longeway, Dominic McIver Lopes, Michael J. Loux, E. J. Lowe, Steven Luper, Eugene C. Luschei, William G. Lycan, David Lyons, David Macarthur, Danielle Macbeth, Scott MacDonald, Jacob L. Mackey, Louis H. Mackey, Penelope Mackie, Edward H. Madden, Penelope Maddy, G. B. Madison, Bernd Magnus, Pekka Mäkelä, Rudolf A. Makkreel, David Manley, William E. Mann (W.E.M.), Vladimir Marchenkov, Peter Markie, Jean-Pierre Marquis, Ausonio Marras, Mike W. Martin, A. P. Martinich, William L. McBride, David McCabe, Storrs McCall, Hugh J. McCann, Robert N. McCauley, John J. McDermott, Sarah McGrath, Ralph McInerny, Daniel J. McKaughan, Thomas McKay, Michael McKinsey, Brian P. McLaughlin, Ernan McMullin, Anthonie Meijers, Jack W. Meiland, William Jason Melanson, Alfred R. Mele, Joseph R. Mendola, Christopher Menzel, Michael J. Meyer, Christian B. Miller, David W. Miller, Peter Millican, Robert N. Minor, Phillip Mitsis, James A. Montmarquet, Michael S. Moore, Tim Moore, Benjamin Morison, Donald R. Morrison, Stephen J. Morse, Paul K. Moser, Alexander P. D. Mourelatos, Ian Mueller, James Bernard Murphy, Mark C. Murphy, Steven Nadler, Jan Narveson, Alan Nelson, Jerome Neu, Samuel Newlands, Kai Nielsen, Ilkka Niiniluoto, Carlos G. Noreña, Calvin G. Normore, David Fate Norton, Nikolaj Nottelmann, Donald Nute, David S. Oderberg, Steve Odin, Michael O’Rourke, Willard G. Oxtoby, Heinz Paetzold, George S. Pappas, Anthony J. Parel, Lydia Patton, R. P. Peerenboom, Francis Jeffry Pelletier, Adriaan T. Peperzak, Derk Pereboom, Jaroslav Peregrin, Glen Pettigrove, Philip Pettit, Edmund L. Pincoffs, Andrew Pinsent, Robert B. Pippin, Alvin Plantinga, Louis P. Pojman, Richard H. Popkin, John F. Post, Carl J. Posy, William J. Prior, Richard Purtill, Michael Quante, Philip L. Quinn, Philip L. Quinn, Elizabeth S. Radcliffe, Diana Raffman, Gerard Raulet, Stephen L. Read, Andrews Reath, Andrew Reisner, Nicholas Rescher, Henry S. Richardson, Robert C. Richardson, Thomas Ricketts, Wayne D. Riggs, Mark Roberts, Robert C. Roberts, Luke Robinson, Alexander Rosenberg, Gary Rosenkranz, Bernice Glatzer Rosenthal, Adina L. Roskies, William L. Rowe, T. M. Rudavsky, Michael Ruse, Bruce Russell, Lilly-Marlene Russow, Dan Ryder, R. M. Sainsbury, Joseph Salerno, Nathan Salmon, Wesley C. Salmon, Constantine Sandis, David H. Sanford, Marco Santambrogio, David Sapire, Ruth A. Saunders, Geoffrey Sayre-McCord, Charles Sayward, James P. Scanlan, Richard Schacht, Tamar Schapiro, Frederick F. Schmitt, Jerome B. Schneewind, Calvin O. Schrag, Alan D. Schrift, George F. Schumm, Jean-Loup Seban, David N. Sedley, Kenneth Seeskin, Krister Segerberg, Charlene Haddock Seigfried, Dennis M. Senchuk, James F. Sennett, William Lad Sessions, Stewart Shapiro, Tommie Shelby, Donald W. Sherburne, Christopher Shields, Roger A. Shiner, Sydney Shoemaker, Robert K. Shope, Kwong-loi Shun, Wilfried Sieg, A. John Simmons, Robert L. Simon, Marcus G. Singer, Georgette Sinkler, Walter Sinnott-Armstrong, Matti T. Sintonen, Lawrence Sklar, Brian Skyrms, Robert C. Sleigh, Michael Anthony Slote, Hans Sluga, Barry Smith, Michael Smith, Robin Smith, Robert Sokolowski, Robert C. Solomon, Marta Soniewicka, Philip Soper, Ernest Sosa, Nicholas Southwood, Paul Vincent Spade, T. L. S. Sprigge, Eric O. Springsted, George J. Stack, Rebecca Stangl, Jason Stanley, Florian Steinberger, Sören Stenlund, Christopher Stephens, James P. Sterba, Josef Stern, Matthias Steup, M. A. Stewart, Leopold Stubenberg, Edith Dudley Sulla, Frederick Suppe, Jere Paul Surber, David George Sussman, Sigrún Svavarsdóttir, Zeno G. Swijtink, Richard Swinburne, Charles C. Taliaferro, Robert B. Talisse, John Tasioulas, Paul Teller, Larry S. Temkin, Mark Textor, H. S. Thayer, Peter Thielke, Alan Thomas, Amie L. Thomasson, Katherine Thomson-Jones, Joshua C. Thurow, Vzalerie Tiberius, Terrence N. Tice, Paul Tidman, Mark C. Timmons, William Tolhurst, James E. Tomberlin, Rosemarie Tong, Lawrence Torcello, Kelly Trogdon, J. D. Trout, Robert E. Tully, Raimo Tuomela, John Turri, Martin M. Tweedale, Thomas Uebel, Jennifer Uleman, James Van Cleve, Harry van der Linden, Peter van Inwagen, Bryan W. Van Norden, René van Woudenberg, Donald Phillip Verene, Samantha Vice, Thomas Vinci, Donald Wayne Viney, Barbara Von Eckardt, Peter B. M. Vranas, Steven J. Wagner, William J. Wainwright, Paul E. Walker, Robert E. Wall, Craig Walton, Douglas Walton, Eric Watkins, Richard A. Watson, Michael V. Wedin, Rudolph H. Weingartner, Paul Weirich, Paul J. Weithman, Carl Wellman, Howard Wettstein, Samuel C. Wheeler, Stephen A. White, Jennifer Whiting, Edward R. Wierenga, Michael Williams, Fred Wilson, W. Kent Wilson, Kenneth P. Winkler, John F. Wippel, Jan Woleński, Allan B. Wolter, Nicholas P. Wolterstorff, Rega Wood, W. Jay Wood, Paul Woodruff, Alison Wylie, Gideon Yaffe, Takashi Yagisawa, Yutaka Yamamoto, Keith E. Yandell, Xiaomei Yang, Dean Zimmerman, Günter Zoller, Catherine Zuckert, Michael Zuckert, Jack A. Zupko (J.A.Z.)
- Edited by Robert Audi, University of Notre Dame, Indiana
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- The Cambridge Dictionary of Philosophy
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- 05 August 2015
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- 27 April 2015, pp ix-xxx
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Comment
- Thomas S. Kuhn
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- Comparative Studies in Society and History / Volume 11 / Issue 4 / October 1969
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- 03 June 2009, pp. 403-412
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For reasons which will appear, the problem of the avant-garde, as presented by Professors Ackerman and Kubler, has caught my interest in unexpected and, I hope, fruitful ways. Nevertheless, both on grounds of competence and because of the nature of my assignment, my present remarks are directed primarily to Professor Hafner's rapprochement of science and art. As a former physicist now mainly engaged with the history of that science, I remember well my own discovery of the close and persistent parallels between the two enterprises I had been taught to regard as polar. A belated product of that discovery is the book on Scientific Revolutions to which my fellow contributors have referred. Discussing either developmental patterns or the nature of creative innovation in the sciences, it treats such topics as the role of competing schools and of incommensurable traditions, of changing standards of value, and of altered modes of perception. Topics like these have long been basic for the art historian but are minimally represented in writings on the history of science. Not surprisingly, therefore, the book which makes them central to science is also concerned to deny, at least by strong implication, that art can readily be distinguished from science by application of the classic dichotomies between, for example, the world of value and the world of fact, the subjective and the objective, or the intuitive and the inductive. Gombrich's work, which tends in many of the same directions, has been a source of great encouragement to me, and so is Hafner's essay. Under these circumstances, I must concur in its major conclusion: ‘The more carefully we try to distinguish artist from scientist, the more difficult our task becomes.’ Certainly that statement describes my own experience.
Comment
- Thomas S. Kuhn
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- Comparative Studies in Society and History / Volume 11 / Issue 4 / October 1969
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- 03 June 2009, pp. 426-430
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Possessing little knowledge or competence in either demography or economics, I am in no position to comment on the central portion of Professor Dovring's paper. Fortunately, I feel no call to do so, for I very much doubt that it can be faulted. No refinement of data or analysis is likely to set aside his basic conclusions. If the time intervals analyzed are made long enough to eliminate local fluctuations, accelerated rather than linear growth, whether of population or productive capacity, has characterized man's life on earth since at least the conquest of fire. Only historical myopia can account for the view that an increasing tempo of change dates only from the Industrial Revolution, that our current condition is, with respect to the existence of acceleration, essentially new.
22 - Metaphor in science
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- By Thomas S. Kuhn, Institute of Technology
- Edited by Andrew Ortony, Northwestern University, Illinois
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- Metaphor and Thought
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- 05 June 2012
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- 26 November 1993, pp 533-542
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Summary
If I had been preparing the main paper on the role of metaphor in science, my point of departure would have been precisely the works chosen by Boyd: Max Black's well-known paper on metaphor (Black, 1962b), together with recent essays by Kripke and Putnam on the causal theory of reference (Kripke, 1972; Putnam, 1975a, 1975b). My reasons for those choices would, furthermore, have been very nearly the same as his, for we share numerous concerns and convictions. But, as I moved away from the starting point that body of literature provides, I would quite early have turned in a direction different from Boyd's, following a path that would have brought me quickly to a central metaphorlike process in science, one which he passes by. That path I shall have to sketch, if sense is to be made of my reactions to Boyd's proposals, and my remarks will therefore take the form of an excessively condensed epitome of parts of a position of my own, comments on Boyd's paper emerging along the way. That format seems all the more essential inasmuch as detailed analysis of individual points presented by Boyd is not likely to make sense to an audience largely ignorant of the causal theory of reference.
Boyd begins by accepting Black's “interaction” view of metaphor. However metaphor functions, it neither presupposes nor supplies a list of the respects in which the subjects juxtaposed by metaphor are similar.
Introduction
- Thomas S. Kuhn
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- PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association / Volume 1992 / Issue 2 / 1993
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- 19 June 2023, pp. 2-5
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- 1993
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The Road Since Structure
- Thomas S. Kuhn
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- PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association / Volume 1990 / Issue 2 / 1990
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- 31 January 2023, pp. 1-13
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- 1990
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On this occasion, and in this place, I feel that I ought, and am probably expected, to look back at the things which have happened to the philosophy of science since I first began to take an interest in it over half a century ago. But I am both too much an outsider and too much a protagonist to undertake that assignment. Rather than attempt to situate the present state of philosophy of science with respect to its past — a subject on which I’ve little authority — I shall try to situate my present state in philosophy of science with respect to its own past — a subject on which, however imperfect, I’m probably the best authority there is.
As a number of you know, I’m at work on a book, and what I mean to attempt here is an exceedingly brief and dogmatic sketch of its main themes. I think of my project as a return, now underway for a decade, to the philosophical problems left over from the Structure of Scientific Revolutions.
1 - Introduction
- Bruce R. Wheaton, University of California, Berkeley
- Foreword by Thomas S. Kuhn
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- The Tiger and the Shark
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- 04 August 2010
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- 30 September 1983, pp 1-12
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Summary
For all practical purposes the wave theory of light is a certainty.
This is the story of a radical change in humans' concept of light. In 1896 most physicists were convinced that light consisted of wave disturbances in a medium, the electromagnetic aether. The energy transported in radiation was thought to propagate spherically outward from its source and to spread out over successively larger volumes in space. Thirty years later, a remarkably different concept of light prevailed. Physicists then took seriously the evidence collected over the preceding two decades showing that the energy of radiation does not spread in space. Under certain conditions, light behaves like a stream of particles.
Our subject is more than the story of a shift from one theoretical explanation of radiation to another. This reconsideration of the nature of light was a significant event in our scientific understanding of the world. To resolve the paradox that faced them, physicists rejected the venerable Platonic dictum that the microscopic realm recapitulates the macroscopic; that laws generalized from the behavior of objects in the perceivable world may be applied to the imperceivable one. By 1927 physicists had assigned to all forms of radiation a curious amalgam of wave and particle behavior. Waves spread energy over larger and larger volumes of space; particles do not. Reconciliation of these conflicting properties was possible only through appeal to an ontology that transcended mechanical incompatibility.
Nature was declared to be only imperfectly rationalizable in terms of human experience with macroscopic interactions. The programmatic goal formulated in the seventeenth century to reduce all physical phenomena to consistent mechanical representations was here recognized to be unattainable.
5 - The appeal in Germany to the quantum theory
- Bruce R. Wheaton, University of California, Berkeley
- Foreword by Thomas S. Kuhn
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- The Tiger and the Shark
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- 04 August 2010
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- 30 September 1983, pp 104-132
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Summary
The unit of light energy does not travel in all directions away from an oscillator, but only in a single [direction.]
German-speaking physicists arrived at an explanation for the problems facing radiation theory different from that of their British colleagues. Moreover, their attempt to discover a consistent theory formed a complete contrast to the British attempt. The problems themselves were perceived differently. It would be an exaggeration to say that the problems ever reached the same status as paradoxes in Germany as they did in Britain. Physics as practiced in Germany was not as dependent on conceptual pictures, and physicists there were much more willing to adopt formal principles to solve the difficulties without demanding a consistent physical interpretation.
By 1905 the very word mechanics meant to many Germans something essentially different from its meaning in Britain. Influential voices had proclaimed that matter itself is only a construct of the mind, fashioned out of the more ontologically significant electromagnetic forces that give rise to human perceptions of mass and extension. The more influential Germans were not closely tied to the logical requirements of mechanistic thought. When the electromagnetic impulse hypothesis of x-rays was accepted in Germany, it was interpreted by many as a further example of the versatility of an electromechanical ontology. Electromagnetic impulses were considered by some, most notably those who first tried to make sense of x-ray behavior, as a form of wave with extended properties in space. Consequently, as we shall see in this chapter, the sharp distinction between x-rays and periodic light was never made as strongly in Germany as it was in Britain.
8 - Origins of x-ray spectroscopy
- Bruce R. Wheaton, University of California, Berkeley
- Foreword by Thomas S. Kuhn
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- The Tiger and the Shark
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- 04 August 2010
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- 30 September 1983, pp 199-232
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Summary
[X-rays] are a kind of wave with properties no wave has any business to have.
In the spring of 1912 two research assistants in Munich directed an x-ray beam through a crystal and found that the beam was reformed into a well-defined interference pattern. The property most characteristic of periodic waves – their ability to interfere – is shared by the x-rays. Max Laue, the man chiefly responsible for the discovery, thought he had found proof that characteristic secondary x-rays from the crystal are periodic waves. But H. A. Lorentz quickly pointed out that impulses should interfere too. He showed, in a tour de force argument, that the accepted square pulse is an impossible representation of x-rays. William Henry Bragg and his son concluded that the interference maxima could, indeed, be due to irregular x-ray pulses. But, as such, x-ray impulses were not different from ordinary white light. They supported this claim with a new technique of crystal analysis fully analogous to ordinary optical spectroscopy.
Crystal diffraction provided a new tool for the analysis of x-rays. Pushed furthest by Henry Moseley and Charles Darwin, the technique soon showed that some x-rays comprise periodic wave trains of great length. The extremely sharp angular resolution of observed x-ray interference maxima indicated beyond doubt that x-rays are no different, except in frequency, from ordinary light. Rutherford soon extended the technique to the y-rays. Not only could one isolate characteristic γ-rays, he believed, one could show, with some effort, that they interfere too.
The successful integration of the new spectroscopy with the Bohr atom came, as had x-ray diffraction, from Sommerfeld's Munich.
9 - Quantum transformation experiments
- Bruce R. Wheaton, University of California, Berkeley
- Foreword by Thomas S. Kuhn
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- The Tiger and the Shark
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- 04 August 2010
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- 30 September 1983, pp 233-260
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Summary
Where does the ejected electron get its kinetic energy when its separation from the light source becomes so great that the light intensity almost completely vanishes?
The same x-ray spectroscopic techniques that led to the identification of the atomic origin of x-ray spectra also offered means to test the localization of energy in the radiation. In the second decade of this century, x-ray spectrometers used as monochromatizers provided more purely defined x-rays than had been available from natural characteristic radiation. This, coupled with techniques to determine the kinetic energy of secondary electrons, provided opportunities for precise testing of the quantum transformation relation, E = hv. These experiments form the subject of this chapter.
We are primarily concerned here with the absorption of radiation, not with its emission. To be sure, the quantum regulation of the emission of radiant energy has no classical explanation; yet there is no electromechanical inconsistency implied in the creation of a spherical wave containing a definite amount of energy. It is the inverse case that causes real difficulty. How can that quantum of spherically radiating energy concentrate its full power on a single electron? For this reason, verification of the quantum relationship for emitted radiation lies outside our direct concerns. The Franck-Hertz experiments beginning in 1912, for example, demonstrated the quantum nature of energy transfer, but they did little to encourage acceptance or even consideration of the lightquantum. On the other hand, the experiments detailed here that verified the quantum nature of the absorption of light and x-rays gave substance to the lightquantum hypothesis because they verified the particlelike transfer of radiant energy to matter.
Part II - Ionization and the recognition of paradox, 1906–1910
- Bruce R. Wheaton, University of California, Berkeley
- Foreword by Thomas S. Kuhn
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- The Tiger and the Shark
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- 04 August 2010
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- 30 September 1983, pp 69-70
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2 - The electromagnetic impulse hypothesis of x-rays
- Bruce R. Wheaton, University of California, Berkeley
- Foreword by Thomas S. Kuhn
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- The Tiger and the Shark
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- 04 August 2010
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- 30 September 1983, pp 15-48
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Summary
The Röntgen emanation consists of a vast succession of independent pulses …
Between 1898 and 1912, a majority of physicists thought that x-rays were impulses propagating through the electromagnetic field. Only the extremely large number of pulses gave the x-ray beam its seeming continuity. Although this hypothesis was compatible with the wave theory of light, it was a special case of that theory. Impulses are not ordinary waves. Although they propagate spherically outward from their source, pulses are not periodic oscillations. The energy in an impulse is temporally but not spatially localized. It is contained within an ever-expanding shell, but the shell's radial thickness remains constant and small. Along the circumference, energy is distributed uniformly. But radially, from front to back so to speak, electromagnetic energy rises quickly from zero and drops back just as rapidly. When it passes a point in space, an impulse exerts only a single push or a single push – pull. A pulse collides, rather than resonates, with an atom.
In their temporal discontinuity, impulses differ decisively from their periodic-wave cousins. Light has an intrinsic oscillatory character that allows it to interfere; the superposition of two beams of coherent monochromatic light produces alternate regions of constructive and destructive interaction, the well-known interference fringes. A pulse has no oscillatory structure. Its interference properties are qualitatively different from those of light. A truly monochromatic light wave must extend infinitely in time; if it does not, an intrinsic ambiguity arises in the definition of its frequency. A pulse is restricted in temporal extent, and the very concept of frequency cannot readily be applied.
4 - Secondary rays: British attempts to retain mechanism
- Bruce R. Wheaton, University of California, Berkeley
- Foreword by Thomas S. Kuhn
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- The Tiger and the Shark
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Summary
There is … a reasonable argument that the γ and x rays are also material.
When x-rays or γ-rays strike atoms, electrons and secondary x-rays are emitted. Experiments to sort out the differing properties of the two secondary components produced new and perplexing observations in the first decade of this century. The most perplexing problems concerned the effect of the rays in producing secondary electrons. First, x-rays and γ-rays ionize only a small fraction of the total number of gas molecules through which they pass. Spherically expanding pulses should affect all molecules equally; manifestly, they do not. Second, the velocity that x-rays impart to electrons is many orders of magnitude higher than one would expect to come from a spreading wave. The energy in the new radiations seemed to be bound up in spatially localized packages, available to an electron in toto.
British physicists responded to these paradoxes with attempts to revise, rather than replace, classical electromechanics. J. J. Thomson suggested that old ideas about the microscopic structure of the aether might have to be reformulated. William Henry Bragg concluded that x-rays and γ-rays are not impulses at all but rather neutral material particles. Bragg and Thomson tried at first to find explanations using models based on human experience with machines. Each sought a resolution within the context of classical mechanics; each ultimately failed.
Index
- Bruce R. Wheaton, University of California, Berkeley
- Foreword by Thomas S. Kuhn
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- The Tiger and the Shark
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- 30 September 1983, pp 347-355
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7 - Problems with visible light
- Bruce R. Wheaton, University of California, Berkeley
- Foreword by Thomas S. Kuhn
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- The Tiger and the Shark
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- 30 September 1983, pp 168-196
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Summary
The speaker does not wish to deny the heuristic value of the [lightquantum] hypothesis, only to defend the [classical] theory as long as possible.
Between 1909 and 1912, many influential physicists first realized that the problems preventing a consistent understanding of x-rays applied as well to ordinary light. But unlike the relatively new impulse theory of x-rays, the wave theory of light was exceedingly well founded. It rested on a century's accumulation of experimental evidence. Spatial concentration in the energy of light could not be attributed to a temporal discontinuity, as it could for x-ray impulses. Light was known to be a repeating periodic wave. It was not fully realized at first that hypotheses about the nature of ordinary light required modification. For a decade after 1910, the significance of the growing empirical evidence favoring spatial localization of luminous energy went largely unrecognized. This occurred because the data ran counter to the orthodox view of visible light, the spectral region wherein the periodic properties of radiation were most easily demonstrated and most firmly established.
H. A. Lorentz attacked the problem in much the same spirit, but with quite the opposite intent, as had Einstein. He showed in 1909 that the lightquantum hypothesis is incompatible with the quantum transformation relation itself, let alone with classical ideas about radiation. In so doing, he laid the foundation for a restatement of a major difficulty with any classical explanation of the photoelectric effect: It takes an extraordinarily long time for the observed quantity of energy to build up from periodic waves incident on an electron.
Notes on sources
- Bruce R. Wheaton, University of California, Berkeley
- Foreword by Thomas S. Kuhn
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- The Tiger and the Shark
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- 04 August 2010
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- 30 September 1983, pp xxi-xxiv
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Bibliography
- Bruce R. Wheaton, University of California, Berkeley
- Foreword by Thomas S. Kuhn
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- The Tiger and the Shark
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- 30 September 1983, pp 309-346
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