Die Relativitatstheorien (RT) Einsteins gehoren zu den meistdiskutierten Theorien der Physik des zwanzigsten Jahrhunderts. Nach der Formulie­ rung der sog. 'speziellen Relativitatstheorie' (SRT) im Jahr 1905 nah­ men zunachst nur einige Spezialisten von ihr Kenntnis, bis mit ungefiihr fiinf Jahren Verspatung dann auch zunehmend Nicht-Physiker sich mit ihr zu beschaftigen begannen, angeregt durch populiirwissenschaftliche, all­ gemeinverstiindliche 'Einfiihrungen' von Kollegen Einsteins wie z. B. Paul Langevin in Frankreich oder Max von Laue in Deutschland. Diese Pha­ senverschiebung zwischen fachwissenschaftlichem Ausbau der Theorie (...) und offentlicher Notiznahme wiederholte sich bei Einsteins 'allgemeiner Theorie der Relativitat und Gravitation' (ART). Zwischen 1913 und 1915 in ihren wesentlichen Ziigen ausformuliert, wurde sie erst nach einer spektakuliiren experimentellen Bestatigung im Jahr 1919 einem breiterem Publikum be­ kannt. In meiner Arbeit werde ich den Facettenreichtum der Ausdeutungen, die beide RT erfuhren, zunachst zu referieren und durch repriisentative Zi­ tate aus der Literatur der Zeit zu belegen haben. Der Umfang dieser Arbeit geht wesentlich auf das Konto dieser ausgewahlten Belege - davon verspre­ che ich mir, dafi nicht nur bislang unveroffentlichte Dokumente, sondern auch entlegene Texte hier in ihren zentralen Passagen leicht zuganglich ge­ macht werden. Fernerhin werde ich aber auch zu analysieren haben, warum derartig vielfaltige, einander mitunter diametral entgegengesetzte Interpre­ tationen einer wissenschaftlichen Theorie vorgelegt wurden. (shrink)

Concepts, Experiments, History and Philosophy Daniel Greenberger, Klaus Hentschel, Friedel Weinert. 5. W. Hittorf, Ueber die Elektricit ̈atsleitung der Gase , Annalen der Physik 136, 1–31, 197–234 (1869); Engl. transl. On the Conduction of ...

This book focuses on the gradual formation of the concept of ‘light quanta’ or ‘photons’, as they have usually been called in English since 1926. The great number of synonyms that have been used by physicists to denote this concept indicates that there are many different mental models of what ‘light quanta’ are: simply finite, ‘quantized packages of energy’ or ‘bullets of light’? ‘Atoms of light’ or ‘molecules of light’? ‘Light corpuscles’ or ‘quantized waves’? Singularities of the field or spatially (...) extended structures able to interfere? ‘Photons’ in G.N. Lewis’s sense, or as defined by QED, i.e. virtual exchange particles transmitting the electromagnetic force? The term ‘light quantum’ made its first appearance in Albert Einstein’s 1905 paper on a “heuristic point of view” to cope with the photoelectric effect and other forms of interaction of light and matter, but the mental model associated with it has a rich history both before and after 1905. Some of its semantic layers go as far back as Newton and Kepler, some are only fully expressed several decades later, while others initially increased in importance then diminished and finally vanished. In conjunction with these various terms, several mental models of light quanta were developed—six of them are explored more closely in this book. It discusses two historiographic approaches to the problem of concept formation: the author’s own model of conceptual development as a series of semantic accretions and Mark Turner’s model of ‘conceptual blending’. Both of these models are shown to be useful and should be explored further. This is the first historiographically sophisticated history of the fully fledged concept and all of its twelve semantic layers. It systematically combines the history of science with the history of terms and a philosophically inspired history of ideas in conjunction with insights from cognitive science. (shrink)

ZusammenfassungEs wird die wechselseitige Beeinflussung Einsteins und Schlicks anhand ihrer ab 1915 erhaltenen Korrespondenz in vier Schwerpunkten untersucht. Schlicks Selbstverständnis als Philosoph wie auch einzelne Themata seines Denkens (wie etwa das der Einfachheit) bildeten sich mit seiner Auseinandersetzung um die Relativitätstheorie Einsteins heraus, deren systematische Explikation durch Schlick auf Einsteins Beifall stieß. Als die Ursache für das Auseinanderdriften beider Denker nach 1925 werden fundamentale Differenzen im Wirklichkeitsverständnis und in der Interpretation des Kausalitätsprinzips aufgewiesen, die beide auch zu komplementären Formen der (...) Wissenschaftsgeschichtsbetrachtung führten. (shrink)

An effort of proponents of relativity theory to find evidence for the so-called gravitational red-shift of spectral lines as one of the experimental consequences of Einstein's generalized theory of relativity is reconsidered with reference to hitherto unpublished documents. It is shown how much interest Albert Einstein in fact took, around 1920, in the data analysis of Leonhard Grebe and Albert Bachem, who tried to explain why most earlier efforts to find the gravitational red-shift had failed. They carefully measured the line (...) profiles of the spectral lines both in the sun's Fraunhofer lines and in pressure-independent laboratory comparison spectra. Then they rejected all lines with strong neighbouring lines which could cause apparent shifts of the line centres; the remaining seven well-isolated lines showed the gravitational red-shift with acceptable accuracy. Nevertheless, their claim to have successfully isolated the relativistic effect never convinced the astrophysicists of their day—the reasons for the scientific community's scepticism, contrasted against the enthusiastic group of Einstein sympathizers, are also discussed. (shrink)

The manipulation of materials, and to some extent also their systematic classification, form an integral part of the skills and culture of all societies. Yet it took long for proper sciences to develop out of many processing procedures, tapping the accumulated knowledge about specific material characteristics. In the late 20th century an overarching science of workable materials emerged: materials science. This concept and term originated from major boosts in materials research during WWII and the Cold War, first financed by the (...) U.S. Department of Defense and the Advanced Research Project Agency. The COSMAT-Report from 1974, written by the American Presidential Science Advisory Committee’s „Committee on the Survey of Materials Science and Engineering" four years after its inception, and subsequent reports heralded in the second institutionalization phase of materials science in the USA and with some delay also elsewhere. As the field continued to expand, the demand grew from within in the late 1990s for disciplinary status. This article sorts these claims from the various camps and sets them in the context of unfolding institutional change. The developments within the German-speaking realm, thus far unduly neglected in these debates, are added. I close with a systematic discussion of eight indicator arguments for or against a convergence of this complex field of research into a single coherent discipline. Against Bensaude-Vincent’s thesis that materials science still is an “aggregation of fragments of knowledge", I argue that by 2010 materials science did indeed achieve disciplinary status in a historically rare and enduring process of discipline formation through “emergence by integration" rather than by differentiation. (shrink)

Die Korrespondenz der beiden Physiker und Wissenschaftshistoriker Ernst Mach und Pierre Duhem ist weitgehend, vielleicht mit Ausnahme nur eines Briefes, erhalten. Neben der Dokumentation dieser historischen Zeugnisse setzt sich der Autor in diesem Aufsatz zum Ziel, die jeweiligen Motive, die Mach resp. Duhem zur Beschäftigung mit Wissenschaftsgeschichte führten und die damit verbundenen Modelle der Wissenschaftsgeschichtsentwicklung beider gegeneinander abzugrenzen. Dazu wurden insb. die in der bisher vorliegenden Sekundärliteratur zu Mach und Duhem überhaupt nicht berücksichtigte Buchbesprechung der Machschen Mechanik durch Duhem sowie (...) die ergänzenden Bemerkungen zu Duhem in späteren Auflagen der Werke und in der Korrespondenz Machs herangezogen, die eine recht detaillierte wechselseitige Kritik ihrer Methodik beinhalten. Den Abschluß meiner Betrachtungen bildet der Versuch einer Sondierung dessen, was in Duhems resp. Machs historischen Betrachtungsweisen über die nicht in Frage stehende Bedeutung als Meilensteine der Wissenschaftsgeschichtsschreibung hinaus noch heute von Relevanz ist.The preserved part of the hitherto unpublished Duhem-Mach correspondence, kept in the Archives de l'Académie des Sciences, Paris, and in the Ernst Mach Institut of the Fraunhofer Society, Freiburg im Breisgau, is documented and commented upon. Biographical, methodological, and philosophical analogies and differences between the points of view of Pierre Duhem and Ernst Mach are discussed, and a critical evaluation is given of their impact as historians of science. (shrink)

The ArgumentGravitational redshift of spectral lines as one of the three early-known experimental implications of Einstein's general theory of relativity and gravitation was intensively searched for by researchers all over the world, but around 1920 most of the contemporary evidence in the sun's Fraunhofer-spectrum conflicted with the predictions of relativity theory.In 1923 the American astrophysicist Charles Edward St. John announced that his own solar spectroscopic data would force him to retreat from his former skepticism concerning the existence of gravitational redshift. (...) This statement was at the time widely interpreted by scientists and journalists alike as the open confession of a rapid conversion of one of the few remaining serious scientific opponents of Einstein's theory.This paper demonstrates that this illusion of a sudden “Gestalt switch” in St. John's evaluation of data can be dissolved by a careful step-by-step account of St. John's research practice between 1917 and 1923. After a fine-grained diachronic report of the development of St. John's interpretation of his and others' data, the second part of the paper consists in a systematic analysis of the heuristics and arguments used by St. John pro and contra gravitational redshift. (shrink)

This paper discusses a series of case studies on observations, experiments, and the theoretical interpretation between 1890 and 1960 of a shift of dark Fraunhofer lines in the solar spectrum. I argue for the use of flow charts to analyze interconnections and to identify sequences of research strategies. Also I advocate using a newly-developed tool called "block diagram" representation of experimental systems as an appropriate method to identify recurrent patterns in the interplay of instrumentation, experiment, and theory in research episodes.

ZusammenfassungBei der Durchsicht des Nachlasses von Rudolf Tomaschek fand ich ein 30 Seiten umfassendes Typoskript seines damaligen Assistenten Hugo Watzlawek aus dem Jahr 1944 mit dem Titel „Interatomare Energie“. Heute würde man eher von „inneratomarer Energie“, oder von „Kernenergie“ sprechen, da der Inhalt des Typoskripts „technische Kernphysik“ einschließlich ihrer potentiellen militärischen Anwendungen betrifft. Der Text bietet einen ungefilterten, erstaunlich kenntnisreichen, aber in vielem auch erschreckenden Einblick in die technokratische Gedankenwelt sowie den Wissensstand und Anwendungshorizont eines „technischen Kernphysikers“ im „Dritten Reich“, (...) der unter Verweis auf konkurrierende amerikanische Forschungen 1944 nachdrücklich um weitere Mittel für kernphysikalische und -technische Forschung sowie für die Entwicklung von Kernwaffen bittet. Der vorliegende Aufsatz kommentiert und kontextualisiert das Typoskript; meine ebenfalls online gestellte annotierte Transkription des Typoskriptes bietet ungekürzten Zugang zum Originaltext samt knapper, für dessen Verständnis notwendiger historischer und technischer Erläuterungen.Among the papers of Rudolf Tomaschek I discovered a 30-page typescript from 1944 by his then assistant Hugo Watzlawek entitled “Interatomare Energie”. Nowadays one would rather say ‘inneratomic energy’ or ‘nuclear energy’ since the typescript treats issues of nuclear engineering including its potential military uses. It presents an unfiltered, surprisingly informed view into the technocratic mindset, state of knowledge and application horizon of a “technical nuclear physicist” in the Third Reich. Watzlawek in 1944 urgently petitions for more funding for research in nuclear physics and technology, citing analogous research underway in America. The present paper places the typescript within its historical and technical context. My succinctly annotated transcription of the original text—also made freely available online—provides full accessibility to this document. (shrink)

Loss of the Inner Core: Expectations and Fears for the Future of the History of Science. In this paper, I discuss the current state of history of science in Germany, a combination of strong interest in the field from various neighboring fields (including cultural history, media history, history of art, visual studies) and increasing fragmentation. Powerful institutions such as the Max Planck Institute for History of Science rather encourage this tendency to lose the inner core of the field, a kind (...) of fluidization or vaporization. (shrink)

A translator and her science consultant, who have worked together on many books, consider the problems of translating primary and secondary texts in science. Various problems encountered in translating an ongoing documentary edition in the history of science are discussed using the collected works of Albert Einstein as a test case. For instance, each language has its own preferred sentence structure; moreover, not every historical term finds a perfect equivalent in modern usage, and historical accuracy is contextually bounded.

The paper (given in the section on "Recent work in the History of Philosophy of Science) discusses the method and some of the results of the doctoral dissertation on philosophical interpretations of Einstein's special and general theories of relativity, submitted to the Dept. for History of Science, Univ. of Hamburg, in 1989, also published by Birkhauser, Basel, in 1990. It is claimed that many of the gross oversimplifications, misunderstandings and misinterpretations occurring in more than 2500 texts about the theories of (...) relativity written by scientists, philosophers, and laymen contemporary to Einstein can in fact serve as a clue to a better understanding of the general process by which philosophical interpretations are formed. Another very important source for answering the question of how misinterpretations are formed are hitherto unpublished documents in the estates of physicists and philosophers of that time, including apart from Einstein himself: Bergson, Bridgman, Carnap, Cassirer, Metz, Meyerson, Petzoldt, Reichenbach, Schlick and Vaihinger. (shrink)

This paper describes a now widely forgotten tradition in the nineteenth century which - to borrow a simile used or implied by the actors themselves - may be described as 'spectroscopic portraiture'. Quite unlike the later obsession with numerical precision in wavelength measurement, and also in stark contrast to the contemporary vogue of photographic mapping which presumptuously claimed 'mechanical objectivity', that is avoidance of any human intervention in the recorded data, there was among some spectroscopists a much greater preoccupation with (...) qualitative rather than quantitative aspects. The atlases of the solar spectrum by Cornu, Thollon, and Piazzi Smyth were supposed to convey the subjectively perceived Gestalt of the Fraunhofer lines, at the expense of precision. I shall argue that this was a systematic research programme addressed to a welldefined but small audience of specialists in the new subdiscipline of spectroscopy which was distinct from other practices such as spectrum analysis, which was directed mainly at chemists. Apart from this, the new tradition can also be identified by the dense net of cross-references in the publications of the various members, and by their critique of earlier work. This tradition of spectrum portraiture started with Kirchhoff's 1861-2 high-resolution chromolithographic plates of the solar spectrum, which were printed off a half-dozen different stones in order to render most faithfully the various line intensities. Focusing especially on the tension between representational goals and technical possibilities in the rapidly developing printing industry, I then trace the emerging tradition through its apogee to the close of the nineteenth century. (shrink)

This paper reconstructs what may have led the American professorof chemistry andnatural philosophy John William Draper to introduce a new kind ofradiation, whichhe dubbed `Tithonic rays''. After presenting his and earlierempirical findings onthe chemical action of light in Section 3, I analyze his pertinentpapers in Section 4with the aim of identifying the various types of argumentshe raised infavor of this new actinic entity (or more precisely, this newnatural kind of raybesides optical, thermal and perhaps also phosphorogenic rays).From a modernperspective, all (...) of these obviously belong within theelectromagnetic spectrum,but not so for many thinkers of the 19th century. I close withremarks about whyDraper''s interpretation was abandoned in the second half of the19th century (hehimself recanting only in 1872), and why I think such a naturalhistory ofargumentation (as one might call my approach in Section 4) may beuseful for acomparison-oriented history of science. (shrink)

Comparisons as a Bridge between History and Philosophy of Science. Both in history and philosophy of science, comparisons are looked upon with considerable skepticism. A widespread syndrome of casuitis, i.e., the tendency of historians of science to produce extremely narrow and local studies that do not present a case for any broader thesis of interest to philosophers, has widened the gulf between history and philosophy of science.This may be somewhat surprising to sociologists, philosophers, or general,legal and cultural historians, who have (...) been using comparisons successfully for a long time–albeit not always without controversy. In the first part of this paper, I assess the status of comparisons in science studies, in order to explain why their systematic use is not nearly as natural as might elsewhere be expected. This critical section is followed by a very brief outline of the prerequisites for fruitful comparison as formulated by general and sociological historians in their detailed methodological discussions. To these are added some necessary conditions from the perspective of modern history of science. In the third part I present four examples of such systematic comparisons taken from my own research. (shrink)

In late 1912, Fritz Goos at the Hamburg Physikalisches Staatslaboratorium discovered a systematic dependency of arc-spectra wavelengths on the length of the electric arc used and on its electric parameters, such as, for instance, the current employed. In early 1913, at Heinrich Kayser's better-equipped physical laboratory in Bonn, Goos was able to confirm these effects using a large concave Rowland grating. He was able to establish that variations of between 3 mm and 10 mm in the length of the arc (...) produced wavelength differences of up to 0.02 Å violet shift and -0.007 Å redshift respectively. Further inquiry also revealed a dependency of the wavelength on the region of the arc selected for spectrometric observation. All these surprising effects were soon collectively named ‘pole effect’.As is shown in this paper, the pole effect threatened the validity of the results of the entire research tradition of high-precision spectroscopy which, around 1910, had excelled in establishing several internally coherent systems of wavelength assignments. These wavelength catalogues had been established by spectroscopists such as Heinrich Kayser, Paul Eversheim and their co-workers in Bonn, by August Herman Pfund in Baltimore, and by Charles Fabry and Henri Buisson in Marseille under the aegis of the ‘International Union for Co-Operation in Solar Research’. They had all produced locally consistent, “homogeneous” systems of wavelengths with estimated errors sometimes smaller than 0.001 Å. However, long before 1913, strange non-local inconsistencies had emerged between these systems that were of much greater magnitude than the estimated error. The discovery of the pole effect opened up the possibility that variations in the arc parameters used in the measurements, which the different teams had hitherto not specified, were responsible for the systematic differences, in their respective sets of measurements, coming to up to 0.025 Å.This paper explores the interrelations between local knowledge production, the strategies for the establishment of local coherence, and the ways in which the community of physicists and spectroscopists handled a possible threat to this coherence after 1913. Around 1930, a general agreement was reached about the physical cause of the pole effect, namely Stark effects, caused in turn by intermolecular electric fields of ions in the arc. Much before 1930, however, the community had already succeeded in standardizing the instrumentation used in high-precision spectrometry and had conformed its research practice to such an extent that from 1917 on the pole effect could be routinely circumvented in high-precision spectrometry and interferometry. Thus, experimentation along with its instrumentation, indeed had ‘a life of its own’, independent of the many unsuccessful efforts to explain the pole effect theoretically. (shrink)

The Gradual Formation of the Concept of ‘Light Quanta’. The complex concept of ‘light quanta’ which made its first appearance in Albert Einstein’s 1905 paper on a “heuristic point of view” to cope with the photoelectric effect and other forms of interaction of light and matter, has a rich history both before and after 1905. Some of its semantic layers lead as far back as Newton and Kepler, others are only fully espoused several decades later, yet others initially increased, then (...) diminished in importance and finally vanished. Two historiographic approaches are discussed and exemplified: a) my own model of conceptual development as a series of semantic accretions, and b) Mark Turner’s model of ‘conceptual blending’. Both of these models are shown to be useful and will be further explored in my own efforts to come to grips with the complex process of concept formation. (shrink)

The main features of a new online database of scientific illustrators are portrayed. We list illustrators of scientific publications of all genres (especially atlases, articles, textbooks) who were active between 1450 and 1950, thus excluding illuminators of medieval manuscripts as well as illustrators still active. Currently (Sept. 26, 2012), we already have more than 3,461 entries, with particular emphasis on anatomy, dermatology, botany, zoology, mineralogy, astronomy, and general natural history. Access to the database with its 20 search fields is free (...) and open to all interested users at www.uni-stu ttgart.de/hi/gnt/dsi/. (shrink)

Despite a renewed interest in the philosophical prehistory of logical empiricism, several texts by prominent figures such as, e.g., Moritz Schlick and Hans Reichenbach, published in non-standard journals, have escaped the notice of scholars. Here, a hitherto virtually unknown but significant review of Moritz Schlick's influential book Allgemeine Erkenntnislehre [1st ed. 1918] written by Hans Reichenbach in 1919/20 is reprinted together with comments about its background and the later development, relying on and citing from the unpublished correspondence between Schlick and (...) Reichenbach in 1920. Since they later became the leading figures in the so called Vienna and Berlin circles respectively, this episode marks an important stage in the gradual emancipation of scientific philosophy from its Kantian roots. (shrink)

Summary The growing need for standardized units of measure led to major metrological reforms in the mid-nineteenth century. This paper focusses on their implementation in the Kingdom of Hanover and the involvement of C.F. Gauss. His papers reveal how much the success of his precision measurements hinged on the skill of his mechanic M. Meyerstein. A discussion of the regional weights and measures and the standardization procedure is followed by a description of various precision balances and the weighing methods employed (...) as well as a review of the problems posed by reliable length calibration. The success of the enterprise rested not only on intellectual prestige and ministerial clout but also on the hands-on skill of the mechanical practitioner. (shrink)

For more than twenty years, Macedonio Melloni (1798–1854) experimented with radiant heat rays. Until 1841 he thought of them as ontologically different from light, but in 1842 he converted to the opposite view according to which they are similar in kind, but only differ in wavelength. In this article I analyze the arguments which induced him to change his interpretation of radiant heat and I describe the instruments with which he arrived at these insights.

The paper presents and discusses measurements of gravitational redshift made between 1959 and 1971 by Pound and Rebka, Schiffer and Marshall, Brault, Blamont and Roddier, and finally by Snider. It emphasizes the importance of new measurement techniques such as wavelength modulation, electronic amplification, and scattering of atomic beams to the emergence of new tests of Einstein's GRS prediction, which were perceived by the scientific community as the first ‘clean’ verifications of GRS. In particular, the race to be the first to (...) apply the Mössbauer effect to the GRS problem is described. As soon as the Mössbauer effect was stabilized, it was transformed into a measurement technology that in turn triggered new types of experimental tests of GRS. (shrink)

During Einstein’s lifetime, the special and general theories of relativity were quite frequently interpreted by philosophers. Most of these interpretations actually were misinterpretations. Even today interpretative statements about relativity theory are often false or highly misleading. Why is this so? In my Ph.D. dissertation (Hentschel 1990a), I analyzed (mis)interpretations by 10 different philosophical schools active in the early twentieth century which widely differed in their approaches, emphasis and blind spots. Many of these interpreters – including philosophers of high standing such (...) as Ernst Cassirer, Moritz Schlick or Joseph Petzoldt – had studied the theory intensely and many even had close contact with Einstein himself or with one of the members of his “protective belt” of close friends and allies. Rather than declaring all of these (mis)interpreters as either luminaries or idiots (which would be implausible, if not downright silly), I show structurally how these misunderstandings arose and why they were kind of unavoidable, even for highly qualified and often well-informed interpreters. More popular texts about relativity theory were often second-order interpretations of these first-order accounts, thus multiplying the first-order errors of misinterpretations. I will give a few characteristic examples but my focus will rather be on structural characteristics of these misinterpretations. I will discuss how to analyze them historically by means of interpretational frames. A link will also be made to Ludwik Fleck’s thesis that socially and cognitively stabilized “thought collectives” (“Denkkollektive”) exert strong constraints on human thinking and interpretation (“Denkzwang”). My concept of interpretational frames is one method to formalize and analyze the complex interrelations between different assumptions and inferences within such a frame of thinking (“Denkstil”). Semantic frames and word clouds are also discussed as alternative approaches but both are discarded as unsuitable for the purpose of reconstructing interpretative frames. (shrink)

To compile a comprehensive edition of the correspondence of the world-famous physicist, physiologist, philosopher, and pioneer historian of science, Ernst Mach is an urgent desideratum. An estimated 5000 letters to and from Mach are kept in public and private archives worldwide. The largest part of this correspondence was formerly kept in the Ernst Mach Institut für Kurzzeitdynamik der Fraunhofergesellschaft in Freiburg/Breisgau and is now archived at the Deutsches Museum in Munich. A smaller partial estate, based on collections by Ernst Mach’s (...) son Ludwig has been transferred to the Staats- und Universitätsbibliothek Göttingen. Other major collections are kept in Konstanz, Vienna, Prague etc. Mach’s own letters are spread throughout Europe and North America in hundreds of archives hosting private papers or estates of his contacts. (shrink)

This paper discusses facets of 19th-century scientific photography as a visual culture. The example of spectral research and documentation is particularly well suited, because prismatically diffracted light from the sun or from luminous gases was one of the most frequently examined phenomena of that century. The results were significant not only for physics but also for analytical chemistry and astrophysics. The spectrum also served as an ideal test object for checking the effectiveness of a wide array of photochemically sensitizable surfaces (...) to the various color regions. Scientific photography became the most important experimental technique in the infrared and ultraviolet. H. A. Rowland's spectrum charts are discussed as an example of the transition from comprehensiveness in documentation to fetishism. The discussion of the Lippmann process, one of the first methods of color photography, addresses the associated training of the eye. Issues of authenticity and the much averred „mechanical objectivity” are raised with regard to retouching. The overriding theme of visual science cultures leads furthermore to unanticipated interdependencies with other scientific fields, such as geography, and draws the importance of practitioners into the foreground. (shrink)