Archimedes 44 New Studies in the History and Philosophy of Science and Technology Arianna Borrelli Giora Hon Yaakov Zik Editors The Optics of Giambattista Della Porta (ca. 1535–1615): A Reassessment The Optics of Giambattista Della Porta (ca. 1535–1615): A Reassessment Archimedes NEW STUDIES IN THE HISTORY AND PHILOSOPHY OF SCIENCE AND TECHNOLOGY VOLUME 44 EDITOR Jed Z. Buchwald, Dreyfuss Professor of History, California Institute of Technology, Pasadena, USA ASSOCIATE EDITORS FOR MATHEMATICS AND PHYSICAL SCIENCES Jeremy Gray, The Faculty of Mathematics and Computing, The Open University, UK Tilman Sauer, Johannes Gutenberg University Mainz, Germany ASSOCIATE EDITORS FOR BIOLOGICAL SCIENCES Sharon KinGSland, Department of History of Science and Technology, Johns Hopkins University, Baltimore, USA manfred laubichler, Arizona State University, USA ADVISORY BOARD FOR MATHEMATICS, PHYSICAL SCIENCES AND TECHNOLOGY Henk Bos, University of Utrecht, The Netherlands mordechai feinGold, California Institute of Technology, USA allan d. franKlin, University of Colorado at Boulder, USA KoSTaS GavroGlu, National Technical University of Athens, Greece Paul hoyninGen-huene, Leibniz University in Hannover, Germany Trevor levere, University of Toronto, Canada JeSPer lüTzen, Copenhagen University, Denmark William neWman, Indiana University, Bloomington, USA laWrence PrinciPe, The Johns Hopkins University, USA JürGen renn, Max Planck Institute for the History of Science, Germany alex roland, Duke University, USA alan ShaPiro, University of Minnesota, USA noel SWerdloW, California Institute of Technology, USA ADVISORY BOARD FOR BIOLOGY michael dieTrich, Dartmouth College, USA michel moranGe, Centre Cavaillès, Ecole Normale Supérieure, France hanS-JörG rheinberGer, Max Planck Institute for the History of Science, Germany nancy SiraiSi, Hunter College of the City University of New York, USA Archimedes has three fundamental goals; to further the integration of the histories of science and technology with one another: to investigate the technical, social and practical histories of specific developments in science and technology; and finally, where possible and desirable, to bring the histories of science and technology into closer contact with the philosophy of science. To these ends, each volume will have its own theme and title and will be planned by one or more members of the Advisory Board in consultation with the editor. Although the volumes have specific themes, the series itself will not be limited to one or even to a few particular areas. Its subjects include any of the sciences, ranging from biology through physics, all aspects of technology, broadly construed, as well as historically-engaged philosophy of science or technology. Taken as a whole, Archimedes will be of interest to historians, philosophers, and scientists, as well as to those in business and industry who seek to understand how science and industry have come to be so strongly linked. More information about this series at http://www.springer.com/series/5644 Arianna Borrelli • Giora Hon • Yaakov Zik Editors The Optics of Giambattista Della Porta (ca. 1535–1615): A Reassessment Editors Arianna Borrelli Giora Hon History of Science Department of Philosophy Technische Universität Berlin University of Haifa Berlin, Germany Haifa, Israel Institute for Advanced Study on “Media Cultures of Computer Simulation (MECS)” Leuphana University Lüneburg, Germany Yaakov Zik Department of Philosophy University of Haifa Haifa, Israel ISSN 1385-0180 ISSN 2215-0064 (electronic) Archimedes ISBN 978-3-319-50214-4 ISBN 978-3-319-50215-1 (eBook) DOI 10.1007/978-3-319-50215-1 Library of Congress Control Number: 2017932422 © Springer International Publishing AG 2017 This work is subject to copyright. 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Printed on acid-free paper This Springer imprint is published by Springer Nature The registered company is Springer International Publishing AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Contents 1 Introduction ............................................................................................... 1 Arianna Borrelli 2 A Theater of Experiments: Giambattista Della Porta and the Scientific Culture of Renaissance Naples ........................ 11 William Eamon 3 Giambattista Della Porta: A Magician or an Optician? ........................ 39 Yaakov Zik and Giora Hon 4 Optical Diagrams as “Paper Tools”: Della Porta’s Analysis of Biconvex Lenses from De refractione to De telescopio .......................................................................................... 57 Arianna Borrelli 5 Giambattista Della Porta’s Theory of Vision in the De refractione of 1593: Sources, Problems, Implications ............ 97 A. Mark Smith 6 Magi from the North: Instruments of Fire and Light in the Early Seventeenth Century............................................................ 125 Fokko Jan Dijksterhuis 7 U sing Invariances in Geometrical Diagrams: Della Porta, Kepler and Descartes on Refraction .................................. 145 Albrecht Heeffer 8 F rancesco Maurolico, Giambattista Della Porta and Their Theories on Refraction ........................................................... 169 Riccardo Bellé 9 C onclusion: A Reassessment .................................................................... 201 Yaakov Zik and Giora Hon v Chapter 1 Introduction Arianna Borrelli Giambattista Della Porta (ca. 1535–1615) was an outstanding representative of the vitality and variety of Southern Italian culture in the late Renaissance, but at the same time his work displayed features resonating with the many approaches to the experimental philosophy of nature being developed all over Europe.1 Already in the early years of his long life Della Porta achieved fame at European level with his “Four books on natural magic” (“Magiae naturalis libri quatuor”), published in 1558 and expanded into a twenty-book edition in 1589.2 The “Natural magic” was a collection of experiments on a very broad range of subjects, which were presented in a form appealing to a general audience. Later on, Della Porta took up and expanded upon many of these areas of knowledge in thematic monographs directed at a more learned public. This was the case also with optics, a discipline that in the early modern period underwent a fundamental transformation during which three general areas of natural inquiry which had traditionally been closely linked eventu- ally came to be separated: visual perception and the physiology of the eye, the nature and properties of light, and the geometrical rules of perspective, reflection and refraction.3 In Della Porta’s optical writings the distinctions among these three areas did not yet fully obtain, but were already underway. His works are of particular interest for 1 On Della Porta’s life and cultural context see William Eamon’s contribution to the present vol- ume, which also contains relevant references to sources and secondary literature. 2 Della Porta 1558, 1589. 3 For an overview on the development of pre-modern and early modern optics see: Lindberg 1976, Smith 2015. A. Borrelli (*) History of Science, Technische Universität Berlin, Berlin, Germany Institute for Advanced Study on “Media Cultures of Computer Simulation (MECS)”, Leuphana University, Lüneburg, Germany e-mail: [email protected] © Springer International Publishing AG 2017 1 A. Borrelli et al. (eds.), The Optics of Giambattista Della Porta (ca. 1535–1615): A Reassessment, Archimedes 44, DOI 10.1007/978-3-319-50215-1_1 2 A. Borrelli the history of early modern optics since they represent the first extended and sys- tematic textual sources on the optical artifacts which became available in increasing numbers during the sixteenth-century thanks to the progress in glass-making and glass-working. These developments, and in particular the rise of the epistemic sig- nificance of the telescope, played a key role in leading early modern authors to deal separately with the physiology of vision, the theory of light and geometrical optics. Many references to Della Porta’s optical work were made in context of the dis- pute on the invention of the telescope, a discussion in which Della Porta himself was engaged in the last years of his life. In light of the huge amount of literature on this subject, little if anything remains to be said, and the priority discussion plays no role in the present volume, although the telescope will feature in Fokko Jan Dijksterhuis’ contribution on the reception of Della Porta’s work in the Netherlands. The studies collected here focus on Della Porta’s published and unpublished attempts at making sense of optical phenomena made possible by the newly developed glass artifacts, and aim at reassessing their original content and their role in the development of early modern optics. Della Porta discussed optical themes in four works: – chapter 1 to 19 of book IV of the first edition of “Natural magic” (1558)4 – the whole book XVII of the second edition of “Natural magic” (1589)5 – the treatise “On refraction” (“De refractione”, 1593)6 – the manuscript draft of the unfinished treatise “On the telescope” (“De telesco- pio”, ca. 1610–1615)7 Della Porta’s writings in general and his optical works in particular have not been treated kindly by modern historiography, and he has often been portrayed either as a chaotic, enthusiastic experimenter hopelessly stuck in a medieval worldview, or as a talented showman only interested in amazing and entertaining naive audiences rather than in furthering the understanding of nature.8 To understand the motivations for a reassessment of Della Porta’s optics it is important to look back at how histo- rians have dealt with it, and this is what I will do in the following pages. The over- view does not aim at exhaustiveness, but only at sketching how the present, mainly negative image of the Neapolitan scholar emerged. Della Porta’s contemporaries had a rather high estimate of his optical research: Johannes Kepler is known to have read carefully the optical experiments in the “Natural magic” and sought for a copy of the treatise “On refraction”, which Thomas Harriot used as a basis for his own optical work.9 A relatively long and positive discussion of Della Porta’s optical writings is found in Joseph Priestley’s “History 4 Della Porta 1558. 5 Della Porta 1589. 6 Della Porta 1593. 7 Della Porta 1962. 8 As examples of such views, see the rather old entry on Della Porta in the Dictionary of Scientific Biography (Rienstra 1975) and the more recent one in the Stanford Encyclopaedia of Philosophy (Kodera 2015). 9 Duprè 2008, Goulding 2013. 1 Introduction 3 and present state of discoveries relating to vision, light and colour” (1772), and shorter mentions appeared later in Emil Wilde’s “History of optics” (“Geschichte der Optik” 1838), in Raffaello Caverni’s “History of the experimental method in Italy” (“Storia del metodo sperimentale in Italia” 1891), and in Edmund Hoppe’s “History of optics” (“Geschichte der Optik” 1926).10 However, the person who most extensively studied Della Porta’s optical work was also one of his harshest critics: Vasco Ronchi, eminent scientist and expert of optics, as well as historian of this discipline. In various publications Ronchi discussed in some detail Della Porta’s treatise “On refraction”; he also took care that the manuscript draft of the treatise “On the telescope”, discovered in 1940 in the archive of the Accademia dei Lincei, should be edited with great competence by Maria Amalia Naldoni.11 In a paper pub- lished in 1947 Ronchi gave factually accurate discussions of Della Porta’s treatment of lenses and stated clearly that all phenomena presented by Della Porta were empirically correct. However, although he fully acknowledged Della Porta’s experi- mental capabilities, Ronchi missed in Della Porta’s writing a theory of lenses start- ing from first principles. According to Ronchi, Della Porta’s ray-tracing constructions led to correct empirical conclusions, but they did not prove those conclusions on the basis of some fundamental principles: [Della Porta] belongs to the number of those, and even today there are many, who do not give any importance to the definition of fundamental concepts, a task that they are happy to leave to the philosophers, and instead start from any point of departure, as long as it fit for their operations.12 After describing one of Della Porta’s constructions, Ronchi concluded: As we see, here there is anything but the proof. And the same goes for all other propositions, about a dozen, following the first one. But apart from the logic, there is a content, both an experimental and a theoretical one. The experimental one is more definite, because numer- ous and accurate observations must have been made. […] The most interesting theoretical content consists in the attempt to define the position of the image given by the lens using the intersection of a ray with an orthogonal line, as in the case of plane refracting surfaces.13 Ronchi gave a positive assessment of the experimental content of Della Porta’s work, but harshly criticized his theoretical methodology. The problem, for Ronchi, was not just that Della Porta did not arrive at the law of refraction as stated by later authors, but also that he was not even aiming at anything of the sort: Della Porta was 10 Priestley 1772, 34–43; Wilde 1838 vol. 1, 112–12; Caverni 1891, 536–566; Hoppe 1926, 24–25. 11 Della Porta 1962, Naldoni 1946, 1962, Ronchi 1947, 1962, 1970. 12 “[Della Porta] si mette nel novero di quei non pochi, anche oggi, che non danno peso alla definizione dei concetti fondamentali, opera che essi lasciano ben volentieri ai filosofi, ma partono da una base qualunque, purchè vada bene per le loro operazioni.” (Ronchi 1947, 11). 13 “Come si vede, c’è tutto fuorchè la dimostrazione. E dello stesso tipo sono tutte le altre [propo- sizioni], circa una dozzina, che seguono questa prima. Ma a parte la logica, un contenuto vi è, sia sperimentale, sia teorico. Quello sperimentale è più definito, perchè le osservazioni fatte debbono essere state numerose e accurate.[...] Il contenuto teorico più interessante consiste nel tentativo di definire la posizione dell’immagine data dalla lente, ricorrendo all’intersezione di un raggio con una normale, come a proposito delle superfici rifrangenti piane” (Ronchi 1947, 13–14). 4 A. Borrelli apparently formulating what today’s scientists would call a “phenomenological theory” of lenses. All in all, Ronchi’s discussion of Della Porta’s work in his 1947 paper was less biased than in other works. For example, in his monograph on “The nature of light” (1970, original Italian edition 1939), a book which became well known at the international level, he skipped any praise for Della Porta’s experimen- tal results, and underscored in a more critical tone the (alleged) defects of his theo- retical exposition, stating that Della Porta “was triumphantly writing what we can only call his absurdities on lenses and refraction”.14 Nonetheless, Ronchi in all his writings underscored how Della Porta, togehter with Francesco Maurolico, paved the way for Kepler’s reflections, which for Ronchi represented the turning point from ancient to modern optics.15 Ronchi remained for many decades the only histo- rian who had directly engaged with Della Porta’s optical writings, and his judgment led other scholars to formulate a negative opinion on the subject without delving into Della Porta’s writings to the same extent as Ronchi had done. David Lindberg was the next author who looked more closely into Della Porta’s optical work and he went even further than Ronchi with his critique. Lindberg discussed Della Porta in a paper aimed at disproving Ronchi’s claim that Della Porta and Maurolico “intro- duced important innovations into optical theory, which prepared the way and laid the groundwork for Kepler’s revolutionary activities in the seventeenth century”.16 Lindberg took up Ronchi’s critique that Della Porta’s geometrical constructions were no rigorous proofs, but did not even mention their empirical accuracy and systematic character; at times he even read incorrect interpretations into Della Porta’s propositions.17 Lindberg took issue with Ronchi’s claim that Della Porta’s failures were the failures of medieval optical theory, and noted that Kepler also fol- lowed those principles, but had still managed to develop “an adequate theory of thin lenses”.18 What is, or not, “an adequate theory” is however a question which depends not only on the theory, but also on the criteria of adequacy, and both Ronchi and Lindberg were using modern geometrical optics as a benchmark for their judgment. The contributions in this volume will instead offer a number of other perspectives from which the “adequacy” of Della Porta’s optics can be assessed. Resuming our brief historiographical overview, it is worth mentioning a paper by Johannes Lohne (1963) discussing the history of the law of refraction.19 Lohne describes the rule for refraction in a glass sphere given in Della Porta’s “On refrac- tion” and characterizes it as “benchmark formula” (“Werkstattformel”) which would have provided an estimate of the refraction angle very near to the modern one under the assumption that the glass employed had refracting index equal to 1,5.20 14 Ronchi 1970, 86. 15 Ronchi 1970, 77–109. 16 Lindberg 1984, 131. 17 Borrelli 2014, 50–51, 56. 18 Lindberg 1984, 148. 19 Lohne 1963. 20 Lohne 1963, 157–158.