The first blog entirely devoted to the history of physics.

Anecdotes, philosophical issues, great discoveries, and much more from first-hand participants.


Tuesday, December 6, 2011

The laws of physics

''The concept of physical law, as it is used in modern natural science, does not contain any ideas of command and obedience. Yet it obviously originates in a juridical metaphor. In a well governed state there will be laws which are for the most part observed by the citizens. Lawbreaking will occur comparatively seldom, and will be punished when detected. The more powerful the government and the cleverer the police is, the rarer it will be. Let us suppose now the government to be omnipotent and the police to be omniscient. In this ideal case the behavior of the citizens would completely conform to the demands of the lawgiver and laws would be always observed. With such an ideal state nature was compared in the seventeenth century. The observable recurrent associations of physical events, in which the philosophers and scientists of the period began to be interested, were interpreted as divine commands and were called natural laws. Thus the concept of natural law originated in theological ideas. Later these non-empirical components fell gradually into oblivion. Our historical investigation, therefore, will have to trace the idea of God as a lawgiver to nature and the influence of this idea on the rising natural sciences. Since one is, generally speaking, inclined to consider contemporary ideas as a matter of course and to ascribe them uncritically to thinkers of the past, we shall bring into prominence the differences from modern thinking before the seventeenth century. Finally we shall try to explain sociologically why the concept of physical law was lacking then and why it developed in the period of Descartes, Hooke, Boyle, and Newton.''

In Zilsel, ''The Genesis of the Concept of Physical Law''.

Thursday, November 17, 2011

Deep thinking

''On matters of physics, I always regarded Stephen [Hawking] as an oracle and just a few words from him could yield insights which would have taken weeks of work on my own. I was therefore particularly lucky to share an office with him since this gave me privileged access to there insights. However, Stephen is only human and not all encounters led to illumination. Once, while sharing an office with him at Caltech, I asked him a question about something which was puzzling me. He thought about it silently for several minutes and I was quite impressed with myself for asking something which Stephen couldn't answer immediately. His eyes then closed and I was even more impressed with myself because Stephen was clearly having to think about it very deeply. Only after ten minutes did it become clear that he had fallen asleep!''

Carr, ''Primordial Black Holes'', in Gibbons et al. (eds), The Future of Theoretical Physics and Cosmology: Celebrating Stephen Hawking's 60th Birthday, p. 258.

Thursday, November 3, 2011


''Dirac deeply influenced Tomonaga, and through Tomonaga he had a pervasive influence on an entire generation of Japanese physicists. During the summer of 1935, Nishina, Kobayasi, Tamaki, and Tomonaga – the theoretical group of the Nishina Laboratory – 'devoted' themselves to translating Dirac's 'famous textbook of the quantum theory' into Japanese.
We three rented a small villa at Karuizawa, a famous summer resort of Japan where Nishina stayed with his family. As soon as we started work, we found how difficult it was to translate English into Japanese which has a completely different sentence structure. The work of translation was really heavy labour, and sometimes we became so tired that we all became bad humoured and disputes often arose over trifling matters. But we made it a rule to take a rest on Sundays and on finishing every chapter, to make excursions to neighboring hills and meadows. The beautiful landscapes and refreshing air were so effective that we all recovered our good humour and we were able to continue our hard work. We believe that the Japanese edition of Dirac's book has been and will continue to be appreciated by many physics students of our country. (Tomonaga 1976, pp. 466-467.)''

In Schweber, QED and The Men Who Made It: Dyson, Feynman, Schwinger, and Tomonaga, pp. 255-256.

Sunday, October 16, 2011

Making profit from physics

''Thompson [Lord Kelvin] too was deeply attached to the notion of scientific knowledge or capital which generated compound interest available for reinvestment in intellectual capital or for exploitation in industrial application. Patented inventions represented the latter component in the capitalism of intellectual property, that is, the marketing of the 'materially embodied' products of scientific research to commercial interests.''

In Norton & Wise, Energy and Empire: A Biographical Study of Lord Kelvin, p. 707.

Monday, October 3, 2011

The mathematization of physics

''Our starting point will be the publication of Newton's Principia which marks, conceptually, a radical departure from the then dominant tradition of mechanical philosophy. We defend the thesis that by taking the mathematical route to natural philosophy Newton initiated, or at least accelerated, a series of social, epistemological and even ontological consequences which over the course of a century, redefined the legitimate practice of physics. As we will see, these consequences were indirect and often only confusedly perceived by the actors involved but led finally to the state of affairs we now generally take for granted: that physics is mathematical in its formulation. Far from being obvious, this idea was long debated over the 18th and even the first half of the 19th century as more and more domains of physics lent themselves to mathematical formulations.''

In Gringas, ''What Did Mathematics Do to Physics'', p. 8.

Tuesday, September 13, 2011

Zel'dovich and Pope John Paul II

''After approaching Pope John Paul II with an unidentified object concealed beneath his jacket, Zel'dovich produced a book of his collected papers, which he donated to the Pope. 'Thanks' the Pope replied, to which Zel'dovich loudly responded 'Not just 'thanks'! These are fifty years of my work!'. The Pope kept Zel'dovich's collected papers (Zel'dovich, 1985) under his arm during the entire rest of the audience.''

Ruffini, ''The Ergosphere and Dyadosphere of the Kerr Black Hole'', in Wiltshire et al. (eds), The Kerr Spacetime, p. 79.

Saturday, August 27, 2011

The electric force, the very basic

''Now in order clearly to understand how such attraction takes place, and what those substances may be that so attract other bodies (and in the case of many of these electrical substances, though the bodies influenced by them lean toward them, yet because of the feebleness of the attraction they are not drawn clean up to them, but are easily mode to rise), make yourself a rotating‐needle (electroscope ‐ versorium) of any sort of metal, three or four fingers long, pretty light, and poised on a sharp point after the manner of a magnetic pointer. Bring near to one end of it a piece of amber or a gem, lightly rubbed, polished and shining: at once the instrument revolves. Several objects are seen to attract not only natural objects, but things artificially prepared, or manufactured, or form by mixture. Nor is this a rare property possessed by one object or two (as is commonly supposed), but evidently belongs to a multitude of objects, both simple and compound, e.g., sealing‐wax and other unctuous mixtures.''

In Gilbert, De Magnete, p. 79.

Saturday, August 13, 2011

The magic numbers of the quantum

''It was in the course of similar investigations that Liveing and Dewar discovered in the spectra of sodium and potasium the existence of two series of lines, one of sharp and one of diffuse lines, and established the existence of homologous series, that is, series of lines of the same type in chemically analogous elements. [...].
Three years later, such an empirical formula, the first to comprise correctly all lines of a spectral series, was published by Johan Jakob Balmer, a schoolteacher in Basel. [...]. He therefore expressed the wavelengths of these lines by the formula [in millimeters]

lambda=h m^2/(m^2-2^2) mm

where h=3645.6 x 10^-7 and m=3, 4, 5, 6. Balmer also predicted the existence of a fifth line with wavelength 3969.65 x 10^-7 mm. Informed by von Hagenbach that this line and other additional lines had indeed been discovered by Huggins, Balmer showed in a second paper that this formula applied to all twelve then known hydrogen lines. He also predicted correctly that in the series which subsequently carried his name, no lines of wavelength longer that 6562 x 10^-7 mm would ever be discovered and that the series could converge at 3645.6 x 10^-7 mm. The agreement between the calculated and the observed values of the wavelength was extremely close in the visible region, but for shorter wavelengths slight systematic discrepancies were evident. In view of these discrepancies Balmer expressed some doubts whether the fault lay with the formula or with the data.''

In Jammer, The Conceptual Development of Quantum Mechanics, pp. 65-66.

Thursday, December 23, 2010

Faraday as mathematician

''I ought to say that I accept Amperes theory as the best present representation of facts, but that still I hold it with little reserve. This reserve is more a general feeling than any thing founded on distinct objections to it. Remember I am no Mathematician. If I were one and could go into a closer examination of the theory than is at present possible for me I might have no doubts left; but all my mathematics consists in that rough natural portion of geometry which every body has more or less. Hence the reason why I have never put my facts into terms of Amperes theory; and why I cling to the relations of Magnetic & Electric forces as the simplest I can perceive; these again are readily distinguished in practise and hence the most convenient if not the best for an experimentalist to refer to. I wish most sincerely some mathematician would think it worth his while to do that for the facts which I can not do for them.''

In a letter of Faraday to William Whewell (19 September 1835), in James (ed.), The Correspondence of Michael Faraday, Vol. 2, 1832-1840, p. 278.

Monday, December 13, 2010

Laplace and Bonaparte

''Laplace and Bonaparte were then serving on a commission together with Lacroix to report on an early mathematical memoir of Biot. Bonaparte never made the personal favorite of Laplace that he did of Monge and Berthollet, but in 1807 and 1808 his sister, Elisa, having been elevated to the rank of princess, took up Madame de Laplace and attached her as lady-in-waiting to her court in Lucca. Their correspondence offers glimpse into the Napoleonic world of fashion. On seizing power, Napoleon named Laplace Minister of the Interior. That ministry had responsibility for most aspects of domestic administration other than finance and police. Laplace lasted six weeks in the government, to be replaced by Bonaparte's brother, Lucien. Napoleon's reminiscence at St. Helena is also famous. Laplace, he said, could never 'get a grasp on any question in its true significance; he sought everywhere for subtleties, had only problematic ideas, and in short carried the spirit of the infinitesimal into administration.''

In Gillespie, Pierre-Simon Laplace 1749-1827: A Life in Exact Science, p. 176.

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