The work of the research group headed by Jürgen Renn is mainly dedicated to the understanding of the historical processes of structural changes in systems of knowledge. This goal comprises the reconstruction of central cognitive structures of scientific thinking (both first-order structures such as that associated with the concept of force and second-order structures such as those associated with the notions of experiment and theory, e.g. the concept of causality), the study of the dependence of these structures on their experiential basis and on their cultural conditions (in particular on instruments and external representations), and the study of the interaction between individual thinking and institutionalized systems of knowledge. Thus, the interaction of three major factors in the development of scientific thinking has to be reconstructed: (1) the experiential basis of scientific thinking in a given period (including technical practice as well as scientific experiments); (2) the scientific means and external representations employed (including language, graphical representations, and formalisms); and (3) the cognitive organization and social conditions of the structures of scientific knowledge and thinking. This theoretical program of an historical epistemology is the common core of the different investigations and research projects pursued and planned by the research group.
Historical epistemology in this sense requires an integration of cultural and cognitive studies of science. Methods and results of the cognitive sciences, of the structuralist tradition of psychology as well as of philosophical theories of concept development, can help to compensate for theoretical deficits in the history of science in a narrow sense, in particular when it comes to explaining thought processes. The history of science can, inversely, contribute to overcoming the limitations of theoretical approaches whose claims have not yet been systematically confronted with the results of historical research. However, such an historical epistemology would not only have to add the models and scientific means of the social and cognitive sciences to the traditional methodological arsenal of the history of science, but must also develop a theoretical coherency that goes beyond exploiting historical case studies to flesh out preconceived philosophical opinions.
In order to achieve a broad historical basis for dealing with these theoretical problems and to cover at least some of the major developmental steps in the history of science, research has been inaugurated or is planned in four different areas: the emergence of formal sciences such as mathematics; the emergence of empirical sciences such as physics, chemistry, and biology; structural changes in sciences with developed disciplinary structures and integrated theoretical foundations, such as the transition from classical to modern physics; and the role of reflective thinking and second-order concepts in science.
Present research in these areas focuses on two central projects: (1) the relation of practical experience and conceptual structures in the emergence of science, and (2) studies in the integration and disintegration of knowledge in modern science. Both projects cover several of the above mentioned research areas. The first project seeks to understand the emergence of fundamental concepts of both formal and empirical sciences as a result of reflecting practical experiences, prior to the period in which experiments became the dominating experiential basis of science. The second project studies transformation processes of knowledge organization, in particular in developed sciences, and the role of fundamental concepts (both of the first and second order) in such processes. A further area of work is dedicated to developing advanced tools for an historical epistemology. In this area, new electronic media are used both for exploring new ways of creating access to the empirical basis of the history of science (electronic archives) and for modelling discovery processes in science.
Jürgen Renn (responsible), in co-operation with Peter Damerow, Gerd Graßhoff, Mario Helbing, Wolfgang Lefèvre, Volkmar Schüller, Klaus A. Vogel, Paul Weinig
The history of mechanics illustrates that scientific knowledge long predates the emergence of an experimental tradition. Mechanics, or at least certain parts of it, had already achieved the status and the form of a science in antiquity. Just as with astronomy and mathematics, it played the role of a model science in the Scientific Revolution, and eventually became an integral part of science as we know it today. This peculiar longevity has given rise to speculations that the experiential basis of such scientific knowledge must be of a special kind, distinct from that of other sciences which emerged much later. It has been claimed, for instance, that knowledge in mechanics or in mathematics is rooted in an essentially universal every-day experience or even based on a priori structures of thinking. These and other speculations involve a very restrictive notion of experience, however. They exclude the by no means universal experience that human beings acquire in a historically specific material environment when dealing, for instance, with the technology of their times.
The general relevance of practical experience for the beginnings of such different fields as mechanics, chemistry, or mathematics is rather obvious, considering the significance of balance, of metallurgical procedures, or of field measurements for the emergence of these sciences. The detailed and systematic reconstruction of the role of practical experience for the development of cognitive structures in science, however, has hardly begun. Such a reconstruction encounters indeed numerous difficulties. Practical knowledge is in part "tacit knowledge," in the dual sense that it may involve non-verbal experiences such as acquired skills, but also experiences which can be verbally expressed but were only orally transmitted. An additional difficulty is caused by the way in which practical knowledge is usually transmitted. In spite of important innovations, the tradition of canonical solutions is, for instance, a characteristic feature of practical mechanics at least until the fifteenth century. To the extent that this continuity is essentially achieved by copying well-established model solutions, the knowledge of the practitioner necessary to create such solutions often escapes historical reconstruction. Albert Presas i Puig, one of the Institute's Rathenau Fellows, explored the manner in which the knowledge about model solutions was structured for technologies relevant to mechanics. He studied Vitruv's "modular approach" as an example of a very efficient system of rules for adapting exemplary solutions to the changing size relations of the elements, e.g. of a building or a machine. The methodological instruments of traditional history of science, such as narrative descriptions, are inadequate to concisely analyze this and other aspects of the qualitative logic of practical knowledge. An alternative is provided by the analytical tools of cognitive science, which allow the reconstruction of object-specific knowledge in terms of "mental models," which can represent such knowledge in its internal systematics and intersubjective validity.
The goal of the project is to study the role of practical experience for the emergence and development of fundamental scientific concepts, such as those of number, force, and motion. Presently, investigations are being pursued in two different areas: the emergence of fundamental concepts of mathematics in the context of practical, in particular administrative experiences of ancient civilizations; and the emergence of fundamental concepts of mechanics in the context of practical, in particular technological experiences in antiquity and in the early modern period. In both cases, one finds that thinking can be reconstructed in terms of a variety of mental models which partly fulfilled functions in specific contexts of application which later are covered by abstract concepts such as those of number or force. A mental model based on manipulating object-specific symbolic notations, for instance, served in Mesopotamian civilizations for accounting purposes - without presupposing an abstract number concept. Similarly, dynamical explanations in pre-modern mechanics did not make use of an abstract concept of force but of a qualitative mental model, in which a projectile continues its motion because it has received an "internal motor" (called "impetus") from the original cause of motion. The reconstruction of such mental models makes it possible to concisely describe structures of thinking related to practical experience and hence to understand the role of this experience for the emergence of fundamental theoretical concepts such as number or force.
Investigations related to the role of practical experience for the emergence of formal sciences were pursued primarily by several of the Institute's distinguished guest scholars, in collaboration with Peter Damerow and Gerd Graßhoff. Peter Damerow investigated the relation between practical geometry (surveying) in the third millennium B.C. and geometrical techniques of later Babylonian mathematics. Gerd Graßhoff analyzed the observational practices underlying the Babylonian Astronomical Diaries (800 - 100 B.C.). Jöran Friberg explored the development of various techniques from the proto-literate period (before 3000 B.C.) up to Old Babylonian mathematics (around 1800 B.C.), in particular the reflection of brick technology by Babylonian mathematical procedures. James Ritter worked on the determination of third millennium Egyptian metrological systems. Blahoslav Hruka studied the evolution of the technological practices in the agricultural landscape of Ancient Egypt and Mesopotamia and the reflection of these practical experiences by a textual tradition.
The main focus of activities currently is the preparation of a systematic exploration of the role of practical experience for the emergence of the fundamental concepts of mechanical knowledge. Peter Damerow, Wolfgang Lefèvre, and Jürgen Renn have made preliminary studies of the role of theoretical traditions as well as of practical experience for the emergence of a preclassical mechanics in the early modern period. Paul Weinig has worked on a systematic reconstruction of the various lines of transmission of theoretical mechanics from antiquity to the Middle Ages. Mario Helbing has analyzed the reception of Pseudo-Aristotle's Mechanical Questions in the early modern period. Klaus A. Vogel and Gerd Graßhoff have studied broader contexts of mechanical knowledge in this period (cosmography and astronomy, respectively). Volkmar Schüller has completed a new German translation of Newton's Principia, and is working on a detailed analysis of its sources.
Peter Damerow, Wolfgang Lefèvre, and Jürgen Renn
The early modern period saw the creation of a preclassical mechanics which merged theoretical traditions going back to antiquity and a new wealth of practical experience. In order to prepare a systematic study of the role of practical experience in this process, several historical preconditions for the emergence of preclassical mechanics are being examined, among them the tradition of theoretical mechanics and the rise of a "reflecting practical mechanics."
A small corpus of writings (by Pseudo-Aristotle, Pseudo-Euclid, Archimedes, Heron, and Pappus) documents a theoretical mechanics of antiquity which was transmitted to the West bit by bit between the thirteenth and seventeenth centuries, and in part by way of Arabic treatises belonging to this tradition (in particular the "Liber Karastonis"). A first productive appropriation of this tradition occurred in the thirteenth century. A small group of treatises from this time, ascribed to Jordanus Nemorarius, was transmitted in the fourteenth and fifteenth centuries and was partly printed in the beginning of the sixteenth century.
In these writings, elementary mechanical questions are treated on the basis of idealized, geometrically-represented machines, using mathematical means of deduction such as Euclidean geometry and the theory of proportions. Although the preserved corpus of antique and medieval treatises on mechanics is by no means uniform, a preliminary analysis indicates that it corresponds to the transmission of a stable core group of theorems. The proofs of these theorems, on the other hand, are embedded in diverse conceptual frameworks, in particular that of Aristotelian natural philosophy and Archimedian statics.
Medieval scholastics nevertheless juxtaposed the treatises of the different strands, just as it did with other doctrinary traditions, without constructing a consistent mechanics from them (see below). In this way, the potential which the incompatibilities between the different conceptual frameworks would have represented remained unexplored. This observation suggests a more general question to be pursued in the course of the project: were the idealized representations of machines and the deductive apparatus in this tradition only used as a means of justification in order to derive a stable core group of propositions in different ways, and was it in contrast the characteristic feature of the productive appropriation of this tradition in the sixteenth century to probe the consequences of these theoretical tools and to use them for reflecting upon new experiences?
A social precondition for this productive appropriation was the emergence of instances of mediation between practical and theoretical knowledge, in mathematics as well as in mechanics. From antiquity forward, practitioners have employed geometrical construction techniques as well as arithmetical algorithms for the solution of complex tasks. Documents which reveal the use of practical geometry in architecture, in the construction of machines, and in geodesy are important clues for the reconstruction of cognitive structures underlying challenging engineering tasks, and hence constitute an important focus of the project. The application of mathematics, which spread in early modern times in the context of the use of perspective and the construction of scientific instruments, distinguished itself from this tradition of practical geometry by presupposing a more or less complete understanding of the theoretical foundations of geometrical techniques. In this way, points of contact between practical and genuinely theoretical knowledge emerged, creating mediatory instances between practical and theoretical mechanics - between engineers and instrument makers, educated in mathematics and in mechanics, on the one hand, and scientists familiar with practical problems, on the other.
It is on the background of this social network that preclassical mechanics emerged. It manifested itself in works by Tartaglia, Commandino, Benedetti, Guidobaldo del Monte, Galileo, and others. With all the differences between its various strands, preclassical mechanics is characterized by a number of common features: a more or less encompassing familiarity with the antique and medieval traditions of theoretical mechanics, including its conceptual diversity and incompatibilities; the inclusion of practical experiences in theoretical reflections; the establishment of relations between mechanical problems and wider contexts of natural philosophy; and the exploration of new consequences of the traditional means of deduction. Preclassical mechanics still lacked, on the other hand, essential presuppositions on which classical mechanics is founded, particularly the concept of inertia and the Newtonian concept of force.
Preclassical mechanics did not only encompass the work of those who more or less directly picked up antique or medieval theoretical traditions but also a specifically early modern "reflecting practical mechanics." This mechanics dealt with highly complex technical problems (rigidity of bodies, friction, etc.) which could not be successfully tackled with the means of theoretical mechanics then available. Leonardo's drawings illustrate that figurative representations of possible solutions of a technical problem served as the characteristic means of reflection in practical mechanics. It remains to be analyzed whether the books on machines which became popular in the sixteenth century (as well as the illustrated manuscripts of the fifteenth century) were not perhaps also representational means for reflection in practical mechanics, in addition to their other well-known functions (presentation for the court).
A typical example of this reflecting practical mechanics, the first of Galileo's "two new sciences" (dealing with the rigidity of bodies and presented in the first "Days" of the Discorsi), shows that the separation of this mechanics from theoretical mechanics is an artifact of the history of science. This separation of practical from theoretical mechanics, and the almost exclusive concentration on theory rather, reflects the difficulty of adequately reconstructing the peculiar cognitive structures of practical mechanics. Such a reconstruction is, however, necessary not only in order to gain a more complete picture of preclassical mechanics, but also in order to understand what the embedding of theoretical mechanics in this new context of practical experience meant for its development.
Technical innovations in the construction of machines in the fifteenth and sixteenth centuries are important aspects in this context. Their study in the project does not aim at a history of technology, but at a comprehension of objects of experience which could have played a role in the reflections of both practical and theoretical mechanicians. These innovations consisted in new combinations of traditional elements of machines, such as lever and wheel, and in the introduction of new elements, such as flywheel and pendulum. New experiences constituted in any case the basis for an enlarged range of application of the traditional concepts of motion and force, which may have also had structural consequences for the meaning of these concepts. For the analysis of the role of technological innovations in this process, it is not relevant how wide-spread or exceptional they were but only how widely diffused the knowledge of these inventions was.
The role of practical experience as an object of reflection for theoretical mechanics may be illustrated by the second of Galileo's "two new sciences" (dealing with the theory of motion and presented in the Third and Fourth "Days'' of the Discorsi), in which the pendulum and projectile motion are key subjects. Similarly to other protagonists of preclassical mechanics, Galileo attempted to treat these motions with the conceptual instruments of traditional theoretical mechanics. In order to bridge the gap between the idealized simple machines of traditional mechanics and these novel problems, Galileo made use of a technique familiar from practical mechanics, the combination of simple machine elements according to a tool-box principle. In this way, he assembled simple new "mental models" of processes of motion, such as the generation of projectile motion by the fall along an inclined plane, followed by a deflection into the horizontal, and a subsequent free fall. Galileo's research on mechanics, as it is documented for over 30 years by his manuscripts, consisted in the "stabilization" of such mental models and the elaboration of their consequences, as well as in attempts, which were often in conflict with the first approach, to integrate these mental models into an overarching deductive theory of motion.
This complex process of explorations and adaption of fragments of knowledge was not completed when Galileo published his results in the Discorsi. It was further pursued by his disciples, as well as by other scientists of the preclassical period, without changing fundamental conceptual structures of preclassical mechanics. In the course of this process, an increasing range of practical experience found its way into the horizon of theoretical reflection. The reconstruction of the precise role of practical experience for the conceptual transformations taking place in the transition from preclassical to classical mechanics is a central goal of the project.
The medieval traditions of mechanics were based on various sources: from Greek antiquity (i.e. Aristotle, Archimedes, Euclid), which were transferred to Latin Europe either through Arabic translations and emendations (e.g. by Thabit ibn Qurra) or through direct translations from the Greek; as well as original contributions by medieval European scholars, drawing directly or indirectly on those ancient treatises.
Jordanus de Nemore (Nemorarius), one of the most important of these medieval scholars, is the focus of Paul Weinig's study. Particularly the treatises attributed to Nemorarius or his followers on the "science of weights," which further developed Greek and Arabic traditions, constituted the core of medieval knowledge in statics. The study has two main purposes: to explore the extent and the scope to which the ancient traditions were adopted and investigate how those traditions have been modified; and to study the impact of these medieval treatises on the emergence of classical mechanics in the Early Modern era.
Until now, research (among others by Pierre Duhem, Ernest Moody, Marshall Clagett, Joseph E. Brown, and Ron B. Thomson) has been oriented towards the edition and exegesis of these texts rather than towards their reception. The history of this reception, aiming to contextualize these texts within the medieval traditions, still remains to be undertaken. As a first step, the corpus of the Jordanus codices has been systematically recorded in an electronical database. The codices have been extensively catalogued, described, and subjected to a codicological analysis. The most important and exciting result of this systematical search was the discovery of some additional Jordanus manuscripts, soon to be published, which were unknown to researchers. The codicological analysis has already revealed some surprising results: there are clear indications in a few codices that Jordanus belonged to the medieval canon, which was used in the quadrivium at universities in the fourteenth and fifteenth century. Jordanus' connection to the canon will be further investigated in a forthcoming publication. The role his texts played in the sixteenth and seventeenth centuries is the theme of an ongoing study.
The treatise Quaestiones mechanicae of Pseudo-Aristotle was almost unknown in the Middle Ages. In the sixteenth century, however, it was translated into several modern languages, circulated widely, quoted, and discussed by many authors. Its conceptual linkages to Aristotelian natural philosophy and its many references to practical problems provided points of contact not only with theoretical discussions but also with contemporary practical experiences of the early modern period. The texts related to the Quaestiones mechanicae therefore constitute a well-defined corpus which provides an opportunity for an exemplary study of how the growth of practical experience was reflected by the development of mechanical terminology.
In 1995 Mario Helbing collected and listed systematically the sixteenth- century editions of the Quaestiones mechanicae and the related sixteenth- century literature (Alessandro Piccolomini, Giovan Battista Benedetti, Francesco Maurolico, Francesco Buonamici, Niccolò Tartaglia, Bernardino Baldi, Henry de Monantheuil, Giuseppe Biancani, Galileo Galilei, Giovanni Guevara) and transcribed the influential Latin translation by Niccolò Tomeo (1562) into an electronic edition of the text. The electronic text includes modern critical translations and selected commentaries from the sixteenth century, especially the related paragraphs of Benedetti's Mechanica, which will serve as a central tool for the investigations of the productive reception and impact of this treatise in the Early Modern era.
Investigations of the technical vocabulary of mechanics were begun with other members of the group and will be continued in the context of a research project at the Eidgenössische Technische Hochschule Zürich (see under "Activities of the visiting scholars and research fellows"). These efforts are dedicated to exploring the relationships between the terminologies used in various literary traditions: early modern translations (into Latin, Italian, French, German, and Spanish) of treatises on mechanics from antiquity (Pseudo-Aristotle, Archimedes, Heron, and Pappus) and from the Middle Ages (in particular by Jordanus), early modern engineering treatises such as those by Ramelli, Fontana, Specklin, etc., and early modern treatises on mechanics which had a significant impact in the period from 1550 to 1650, such as those by Tartaglia, Cardano, Benedetti, Guidobaldo del Monte, Stevin, and Galileo. The primary goal of this research is to analyze the initial basis and the further development of technical terminology in several European languages (scholar's as well as layman's languages), which are conceived of as representations of mechanical knowledge.
Gerd Graßhoff and Klaus A. Vogel
In Aristotelian physics, the doctrine of the four elements, the doctrine of their natural places, the contrariety between heavy and light, and the distinction between natural and violent motions mutually support each other. Mechanics and cosmology are hence inextricably interwoven, an interrelationship which was a central presupposition of preclassical mechanics. Galileo's attempts to harmonize his theory of terrestrial motion with an explanation of planetary motion illustrate that no fundamental concept of mechanics could be formulated without taking its cosmological references into account.
Aristotelian cosmology did not, however, allow a harmonious integration of conflicting concepts in the fields of mathematical astronomy and geography. Thus, developments which were suitable to clarify conceptual alternatives in astronomy and cosmography/geography were also of crucial importance for evaluating the conceptional possibilities of mechanics.
At the Institute, such developments are presently the objects of study in two areas, which are both directly relevant for understanding the impact of practical experience on the transformation of conceptual systems: the "cosmographic revolution" at the turn of the fifteenth to the sixteenth century; and Kepler's research on planetary motion at the turn of the seventeenth century.
In his dissertation Sphaera terrae. Das mittelalterliche Bild der Erde und die kosmographische Revolution (Göttingen 1995), Klaus A. Vogel reconstructed a lively medieval debate on the relative size and spatial position of the spheres of earth and water and the transformation of this debate through the practical experience of overseas discoveries. Pursuing earlier research by Wilhelm Schmidt, Giuseppe Boffito, Pierre Duhem, William Randles, Edward Grant and others, Vogel sees the "cosmographical revolution" as a specific turning point in the relative importance of theory-based and empirical arguments, because of the growing knowledge about the spatial distribution of land and water. According to Aristotelian natural philosophy, the sphere of water should surround the sphere of earth. The relatively small habitable part of the surface of the earth emerges in places because of an unequal distribution of the elements, due to a displacement of the center of the earth's sphere relative to that of the water's sphere. The discovery of land masses in opposition to the known oecumene thus transformed habitable earth, in radical opposition to Aristotelian doctrine, from an exception requiring specific explanation to a general cosmographic fact.
In a new study, Vogel investigates the impact of the cosmographic revolution on the development of early modern astronomy and mechanics. Copernicus built his heliocentric theory upon the cosmographic state of the art, as is evident from his Commentariolus, dated between 1502 and 1514, and from his famous De revolutionibus orbium coelestium (Nürnberg 1543). Indications of a broader reception and a paradigmatic use of the "cosmographical revolution" shall also be explored in the field of terrestrial mechanics. From the replacement of the Aristotelian hierarchy of spheres by a "terraqueous globe" Copernicus and Galileo have apparently drawn, either indirectly or directly, arguments in favor of a new mechanics. Galileo's theory of the tides, for instance, depends on the new knowledge about the distribution of water and land masses and its conceptualization in terms of a "terraqueous globe."
In his Astronomia Nova, Kepler describes his extensive struggle to base a physical theory of the motions of the planets on Tycho Brahe's observational data. While the impact of the laws of planetary motion he eventually discovered on the further development of mechanics and in particular of Newtonian dynamics is well known, Kepler's own dynamics and its heuristic role for his research are still hardly understood.
Continuing earlier unpublished work by Otto Neugebauer and using special software for constructing computer models of geometric and kinematic relations, Gerd Graßhoff analyzes Kepler's numerical calculations, both in the Astronomia Nova and in his manuscripts. His aim is to reconstruct Kepler's intermediary models of planetary motion and the heuristics motivating these models. Preliminary findings indicate that Kepler's research can be described as "preclassical astronomy" in close analogy to the "preclassical" character of contemporary mechanics: close familiarity with the antique and medieval traditions of theoretical astronomy; extensive and flexible use of their techniques in order to reflect new empirical knowledge; the treatment of astronomical problems in the context of other aspects of natural philosophy, including applications of mechanics to these problems; and the elaboration of new consequences of the traditional means of deduction, such as the construction of an elliptic orbit by means of an epicyclic model. Similar to preclassical mechanics, Kepler's research in preclassical astronomy also involved mastery of techniques familiar from practical experience, in particular the determination of orbital positions in his models by a method of triangulation, not common in traditional theoretical astronomy. In order to facilitate the use of this research by other scholars, the electronic models reproducing Kepler's numerical calculations will also be made accessible.
Newton's Philosophiae Naturalis Principia Mathematica should not only be considered as the beginning of an entirely new era, but also as representing a crowning achievement of early modern physics. The transition from early modern physics to Newton's physics is still badly understood. This state of affairs is also reflected by the lack of a translation of Newton's work into a modern language which satisfies the standards of modern history of science.
In 1729 the third edition of Newton's Principia was translated by Andrew Motte into English. In 1934 this translation was revised by Florian Cajori after the model of the German translation, published by J. Ph. Wolfers in 1872. But this German translation uncritically uses the terminology of the nineteenth century and even translates statements by Newton into modern mathematical equations. Furthermore, these translations do not take into consideration the variant readings in Newton's manuscript, nor the first and second editions, nor the annotations in Newton's hand in his own copies. These important additional textual elements were assembled by Koyré, Cohen, and Whitman in their edition of Newton's Principia, which they published in 1972. This edition is not easy to use, however, because the Latin text is sometimes badly arranged. For all these reasons a new translation of Newton's Principia into a modern language has been a desideratum for a long time.
Volkmar Schüller has now completed a new German translation of Newton's Principia, which is presently being prepared for publication. This new German edition will contain a German translation of the three versions of the Principia, published by Newton in the years 1687, 1713 and 1726, respectively, a German translation of Newton's manuscript for the edition of 1687, as well as a German translation of the annotations in Newton's hand in his own copies of the three editions and in Locke's copy, given to him by Newton. The planned book will also describe the intricate genesis of Newton's Principia and will provide information about the sources used by Newton. Furthermore, this new edition will contain German translations of the reviews, published in contemporary scientific journals, such as Acta Eruditorum, the Journal des Savans, and others.
Jürgen Renn (responsible), in co-operation with Peter J. Beurton and Ohad Parnes (biology), Gerd Graßhoff, Wolfgang Lefèvre, Renate Wahsner, and Falk Wunderlich (philosophy), Leo Corry, Hubert Goenner, Dieter Hoffmann, Michel Janssen, Edward Jurkowitz, Horst Kant, Alexei Kojevnikov, Folkert Müller-Hoissen, James Ritter, Tilman Sauer, and John Stachel (modern physics), Giuseppe Castagnetti and Britta Scheideler (history)
It is remarkable that in some fields and in some historical situations, a vast array of scientific knowledge is structured by only a handful of concepts. The concepts of space, time, force, motion, matter, and a few others played this role for classical Newtonian mechanics; the concepts of species, gene, selection, variation, and adaptation for classical evolutionary biology; the concepts of cell, bacterium, pure culture, and infection for classical microbiology. In retrospect, such core groups of concepts may appear to constitute the starting point for gaining scientific knowledge in their respective fields. A closer historical examination shows, however, that such core groups of concepts usually achieved their privileged position in the organization of knowledge only after a long process of knowledge integration, in a material, social, and cognitive sense. Knowledge integration in turn requires material embodiments, such as an experimental arrangement or a formalism, which can be assimilated to cognitive structures belonging to the different branches of knowledge to be integrated, and a social organization allowing scientists to actually bring the combined knowledge of the different branches to bear on such material embodiments. The emergence of a core group of foundational concepts in the course of or as the sequel to such integration processes must therefore be analyzed as a restructuring of the cognitive organization of previously-acquired knowledge. Earlier studies of this process by participants of the project were dedicated to the reconstruction of the emergence of key concepts of evolutionary biology (Lefèvre) and of classical mechanics (Renn). A case study pursued in the context of the project complements these earlier studies by a parallel analysis of the little-known case of the emergence of foundational concepts of microbiology.
Reflective thinking plays an important, but not yet well-understood role in such restructuring processes. This is particularly evident in historical attempts to provide a philosophical synthesis of scientific knowledge. The project therefore comprises case studies on the role of reflective thinking in philosophical integrations. Their subjects are: the reflective integration of key concepts of early modern science in Kant's natural philosophy; the reflection of Newton's integration of different concepts of force in philosophical interpretations of classical mechanics; and the reflection of foundational debates in contemporary physics by Wittgenstein's early attempt to achieve a philosophical integration of science. It is a common feature of these examples that foundational, first-order concepts of a particular body of knowledge, such as the concept of force, are exploited in attempts to achieve such a philosophical integration, and, in the process, are assimilated to new second-order, reflective structures of knowledge. These new structures, such as a new concept of nature, in turn transform and stabilize the meaning of the first-order concepts.
The foundational concepts which emerged from the first ground-breaking periods of knowledge integration, such as those of space and time in the case of classical physics, proved to be extremely stable in the face of an enormous growth of knowledge in the course of the further development of science. In fact, they were occasionally even considered to be of an a priori status, not subject to any changes by the accumulation of knowledge. Nevertheless, most scientific disciplines have witnessed fundamental changes of precisely this core group of foundational concepts in the past century. These fundamental changes were preceded by more or less extended periods of knowledge disintegration, in which the established cognitive organization of knowledge became problematic. Paradoxically, it appears that the essential mechanisms at work in these periods of destabilization were of the same nature as in the original processes of knowledge integration. For the case of the transition from classical to modern physics, which presently is a central area of research on these mechanisms at the Institute, this affirmation is supported by the crucial role of borderline problems for this transition.
By the end of the nineteenth century, physics had evolved into three major branches, each treating a set of interconnected physical problems on the basis of a relatively stable theoretical foundation. The most ancient of the theoretical foundations of physics was classical mechanics. Electrodynamics (including optics) and thermodynamics also had been established as similarly stable foundations for their respective ranges of phenomena. Among the many concrete, unsolved problems studied by contemporary scientists, several were related to more than one theoretical foundation, such as the problem of the electrodynamics of moving bodies, which requires the application of both the laws of electrodynamics and of the laws of motion from mechanics. Heat radiation is another example of this class of borderline problems, produced by a progressive integration of knowledge, which requires the application of both the laws of radiation - covered by those of electrodynamics - and those of thermodynamics. Since these problems fall under the range of application of two different theoretical foundations, they represented not only a potential locus of conflict between partially different conceptual frameworks but also points of departure for their integration into more developed theoretical frameworks. This in turn required a revision of foundational concepts underlying all of classical physics, and hence a disintegration of traditional knowledge structures. Thus, the electrodynamics of moving bodies became the core of the later special theory of relativity, with its new concepts of space and time to which the rest of physical knowledge had to be adapted. Planck's law of heat radiation, another example, was later seen as the first decisive contribution to quantum theory, with its new concepts of matter and radiation which also required a reconceptualization of traditional physical knowledge.
Several case studies are dedicated to examining the structural changes of physical knowledge associated with the introduction of these new theories, as well as the disintegration of classical evolutionary biology due to analogous challenges. In the case of relativity theory, the focus is on the emergence of the general theory of relativity, and in particular on the disintegration of knowledge structures of classical physics induced by the need to describe gravitation in terms of the new concepts of space and time resulting from the special theory of relativity. In the case of quantum theory, work is concentrated on reconstructing research policies relevant to the emergence of quantum mechanics, and in particular on analyzing the refocusing of traditional research activities induced by the discovery of a new common thread ("the quantum"), connecting hitherto separate problems. In the case of evolutionary biology, a case study analyzes attempts at reinterpreting its foundational concepts as a reaction to new insights, such as the increased knowledge about genes due to molecular biology, and the consequences of such reinterpretations for the integrative role of these concepts.
All these cases are characterized by an interaction of heuristic programs, which aim at knowledge integration, and traditional structures of knowledge, be they cognitive or social, which are disintegrating. The heuristic programs are comparable to the philosophical programs of an earlier period mentioned above, although they are now usually formulated from an inner-scientific perspective (which, of course, does not exclude philosophy from having an effect on them), and although they may even take the form of a science policy. In any case, they provide a further example of the crucial role reflective thinking plays the in processes of restructuring knowledge to be studied under this perspective.
Current research activities related to "Studies in the Integration and Disintegration of Knowledge in Modern Science"
Ohad Parnes' research project looks at the origins of fundamental concepts of medical bacteriology and microbiology as a consequence of processes of knowledge integration in the nineteenth century.
The conceptual foundation of modern microbiology was established in the last quarter of the nineteenth century, and is commonly associated with the work of Louis Pasteur, Robert Koch, and their disciplines. But the emergence of its core concepts, such as "parasitism," "pure-culture," and "bacterial species," was merely a successful culmination of the gradual development of concepts and methods since the beginning of the nineteenth century. The aim of the project is to trace the various strands of this knowledge integration and to reconstruct the processes of cognitive reorganization by which a seemingly self-evident conceptual foundation of this knowledge was created.
An example for this foundation is provided by "Koch's postulates." These postulates, although never formulated as such by Koch himself, appear in different forms in Koch's own writings. They essentially claim that to demonstrate the causal role of a bacterial species, it has (1) to be isolated, (2) to be re-introduced by way of inoculation, and (3) to reproduce the disease under examination, typically in a laboratory animal. Koch's postulates were introduced, at least in a de facto fashion, around 1876.
On closer inspection, the postulates, as self-evident as they might appear today, embody, however, a number of novel concepts, such as that of "bacterial species," which emerged in the few decades preceding Koch's work. These conceptual innovations had in turn been developed through a process of the integration of various long-range traditions of scientific and practical knowledge.
In the last year, several of these traditions have been examined:
a) An attempt was made to comprehend the development of microscopical knowledge between 1800-1830, a period scarcely explored until now. It has been commonly assumed that meaningful microscopical knowledge was possible only after the introduction of microscopes free of achromatic and spherical aberrations, around 1830, but historical inquiry has corroborated that it would be wrong to ignore the continuity of the gradual accumulation of knowledge from the pre-achromatic to the achromatic period. Of special importance is work done in this period in microscopical botany, which led not only to a proto-theory of cells, but also to the conceptualization of plant-like micro-organisms.
b) Another line of investigation has been dedicated to the "catalytic" function of the concept of the cell for integrating various hitherto unrelated traditions of knowledge as a preliminary step towards establishing the conceptual foundations of microbiology. As is well known, Schwann published his Microscopical Investigations, which introduced the idea of the cell as the basic and universal unit of all life, in 1839. Schwann's conclusions emerged from attempts to establish conceptual links between his various research endeavors - namely the discerning of the agent responsible for stomach digestion (pepsin), and the demonstration of yeast, a living organism, as the agent of alcoholic fermentation. These two results are usually considered to form parts of separate fields of knowledge - physiology and microbiology, respectively. Their role for the creation of the integrative concept of the cell is reconstructed on the basis of an extensive use of Schwann's laboratory notebooks, hitherto hardly consulted by historians. The cell theory, in turn, served as a basis for a further integration of knowledge, effectively linking, for instance, Virchow's "cellular pathology" - a new theory of morbid processes - to the conceptualization of microscopical organisms, thus creating one of the preconditions for Koch's synthesis.
c) The concept of bacteria, central for medical bacteriology, evolved only after the introduction of the cell theory. The gradual differentiation of bacteria - from the general group of "little animals" ("animalcules," "infusoria") on the one hand, and from other kinds of microscopic plants (fungi, algae) on the other - has been reconstructed as a further, important strand of the process of knowledge integration under study. It could be shown that this process of differentiation was based on earlier knowledge, acquired in the course of microscopic-botanical work, including technical tools (methods of pure culturing), as well as conceptual schemes, such as that of a life-cycle ("Entwicklungsgeschichte") of a microscopical species.
Further research will be dedicated to exploring the medical context of early microbiology.
Wolfgang Lefèvre and Falk Wunderlich
The classical modern sciences in the seventeenth and eighteenth century consisted not only of single theories - for instance of motion in free fall, of percussion, of gravity, etc. - which reached, on the basis of experiments and methodically controlled observations, a hitherto unknown level of intersubjective acceptance, but also of attempts to construct overall theories of nature based on such single theories, which should replace universal natural philosophy in the tradition of Aristotle. Examples are Kepler's "Weltharmonik," Descartes' mechanistic cosmology, Newton's speculations on "active principles," Leibniz' philosophy of "monads," Boscovic' and Kant's dynamism, and Le Sage's atomistic theory. These theories failed, however, to achieve a status of being intersubjectively shared. In retrospect it seems to be clear that the contemporary level of modern sciences provided too small a basis for these ambitious enterprises. Except among historians of philosophy, these overall theories are forgotten today or mentioned only as metaphysical egg shells of this early stage of the modern sciences.
These overall theories do deserve attention, however, if one wants to reconstruct a full picture of the emergence of the modern sciences. In particular, these theories represent, despite their entirely obsolete scientific basis, outstanding examples of the role of reflective thinking in integrating disparate pieces of scientific knowledge. From the perspective of historical epistemology, it is especially interesting to study how first-order concepts of the scientific theories which were to be integrated interacted with second-order concepts in the construction of these global theories. Reflections based on first-order concepts from the whole range of science played a role in both integration and in concept formation in single fields of scientific knowledge.
These processes are being investigated through the example of Kant's natural philosophy. Currently, a detailed documentation of the scientific concepts in Kant's pre-critical writings is being prepared based on an electronic version of the entire body of writing involved. This documentation comprises in particular a list of Kantian notions used in his writings until 1780. Most of the notions will be supplemented by glossary entries, clarifying their meaning and showing parallels to contemporary usage. References to Kant's writings will also be given which contain definitions or give particular insights into the Kantian use of a notion, and the notions will be cross-referenced, thus creating a net of interrelations among them. In order to show the diachronic dimension, each notion will be associated with a brief informational note about the work (represented by year of appearance) in which it occurs.
In 1995, the first selection and ordering of approximately 2000 relevant Kantian concepts was finished. In analyzing the interrelations among these concepts, the system of cross-references became more differentiated, and now includes the categories "Synonyms,""Antonyms," and "Related Notions." In order to clarify for the user if and how concepts play the role of first- and/or -second-order concepts, each of the selected concepts was assigned to one or more areas of knowledge (mathematics, life sciences, etc.) to which it belongs. Preparations for the glossary entries have begun and will be the main task in 1996.
Renate Wahsner (responsible) partly in cooperation with Horst-Heino v. Borzeszkowski
In his work Philosophiae Naturalis Principia Mathematica, Newton discusses the relation of practical mechanics to universal mechanics, as determined by his theory. He shows the former to be the basis of geometry, which "is nothing but that part of universal mechanics which accurately proposes and demonstrates the art of measuring," and is the precondition for and the core of the measurement-theoretical foundation of his theory. By practical mechanics, Newton understands antique mechanics or, more precisely, the theory of the so-called five simple machines: lever, wrench, pulley, wedge, and inclined plane. In his view, this mechanics treats the forces of the hand, while his own, i. e., universal mechanics, treats the forces of nature. This means that Newton understands his classical mechanics as a theory of the forces of nature, including the forces of hand. To the extent that in classical antiquity mechanics was not considered a theory of nature or a theory of jusiV but of tecnh, a synthesis of jusiV and tecnh inheres in this integration of the forces of nature and hand. Therefore, classical mechanics founds a new concept of nature, a concept that is characteristic of the thinking of the Neuzeit.
This project seeks to investigate the problem of how this new concept of nature, synthesizing nature as the objectively existing and the humanly acting, occurs as the subject of classical mechanics, as in its concept of motion, and how this synthesis is reflected by Hegel's natural philosophy. In this context, it will be clarified what role Hegel - in reference to Kant's idea of an organism - ascribes to teleology in his system.
As has been shown in previous investigations, Hegel's adoption of mechanics was considerably determined by the mechanistic concept of mechanics. This project intends to investigate the reasons for and manner in which the mechanization of mechanics was initiated by Voltaire.
The project will include the following activities: a German edition of Voltaire's work Élémens de philosophie de Newton (in cooperation with Horst-Heino v. Borzeszkowski); a discussion on the topic "Hegels Rezeption des neuzeitlichen Bewegungsbegriffs;" a paper on the reasons for the mechanization of mechanics (in cooperation with Horst-Heino v. Borzeszkowski); and a paper on Hegel's natural philosophy.
The physics of the last decades of the nineteenth century was confronted with a striking conceptual heterogeneity among its major subfields. As a response to this heterogeneity, several attempts were made at a conceptual unification, mostly based on proclaiming the core concepts of one subfield to be the basis for the unification of all of physics, if not of all of science. Examples are the so-called mechanistic and electromagnetic world views, and also the world view of "energetics," based on fundamental concepts of thermodynamics. A unifying mechanical theory of all physical phenomena was pursued, in particular, by Kirchhoff, Helmholtz, Hertz, and Boltzmann. Such unifying programs lost their centrality due to the further progress of physics. The attempts to create a consistent, all-encompassing conceptual framework of physics were in fact pushed into the background, as were their claims to an integration of physical knowledge, by the conceptual incompatibilities that became visible with the borderline problems emerging at the boundaries of the competing theoretical frameworks.
In his investigation of late nineteenth-century natural philosophy, Gerd Graßhoff shows that these unificatory programs nevertheless had a lasting impact on the philosophy of science, which transformed some of the first-order concepts relevant to these programs into second-order reflective categories with a normative methodological character. This process is reconstructed for Wittgenstein's Logisch-Philosophische Abhandlung, which is shown to represent such a transformation, in this case of the program of natural philosophy laid out by Hertz's Prinzipien der Mechanik and Boltzmann's lectures in Vienna. Details of Wittgenstein's studies of engineering in Berlin-Charlottenburg could be reconstructed and related to the project since new archival material from Wittgenstein's latter friend Paul Engelmann has been found. It confirms that with a full grasp of its physical content, Wittgenstein used Hertz's Prinzipien as the foundation for the philosophical architecture built in close contention with the logical theory proposed by Russell and Frege.
Leo Corry, Hubert Goenner, Folkert Müller-Hoissen, Michel Janssen, Jürgen Renn, James Ritter, Tilman Sauer, Britta Scheideler, and John Stachel
Einstein's general theory of relativity emerged in reaction to a fundamental conceptual crisis of classical physics, characterized by foundational inconsistencies between classical mechanics, classical electrodynamics and special relativity. Even though the challenge of reconciling classical mechanics and classical, special-relativistic electrodynamics was recognized and taken up by many contemporaries, the conceptual breakthrough to the theory of general relativity of 1915 was achieved largely by Einstein alone. This theory provided the successful revision of the classical theory of gravitation and eventually became part of the canonized knowledge of modern physics.
The emergence of the general theory of relativity has all the characteristics of a genuine scientific revolution: The restructuring and reinterpretation of the fundamental concepts of classical physics involved in the establishment of the theory was a long and complicated process. The new concepts were incompatible with the traditional understanding of classical physics and had to be presented and transmitted to a wider scientific community and to students in a context of justification by publication of review articles and textbooks as well as by the establishment of a new tradition of academic lecturing. The establishment of the new theory also very much determined the further development of physics, by creating both the need to reconsider all branches of physics in the light of the new concepts and to look for possibilities for experimental confirmation. It also created new conceptual problems and constituted new research programs, such as the program of finding a unified field theory. Finally, the revision of concepts of space and time also had a considerable impact on the epistemological and philosophical discussions, even attracting the attention of a non-specialized public and putting the relativity theory and its creator into the focus of a public discussion which widely transcended the realm of scientific debate.
Einstein's path towards establishing a general theory of relativity is well documented by his publications, his correspondence, and in particular by his unpublished research notes, and has been an important topic in the history of twentieth-century physics over the past few years. A careful analysis of the research notes in particular has provided key insights into the details of the process of revising the conceptual foundations of classical physics. On the basis of these new insights a comprehensive reassessment of the emergence of the theory of general relativity from the point of view of an historical epistemology has now become possible.
In collaboration with the Arbeitsstelle Albert Einstein directed by Jürgen Renn and Peter Damerow at the Center for Development and Socialization (Director: Prof. W. Edelstein) at the Max Planck Institute for Human Development and Education, a number of research activities at the Institute have been concerned both with the reconstruction of the emergence of general relativity and with its broader historical context. A regular seminar was held at the Institute where aspects of the history of general relativity, in particular problems of the interpretation of the Zürich Notebook, were discussed jointly. A major event was the "Fourth International Conference on the History of General Relativity," organized by the Institute in collaboration with the Arbeitsstelle, which provided an international forum for discussing all aspects of the history of general relativity and for presenting the results of the various research activities to the scientific community. The local organizing committee consisted of Jürgen Renn, Tilman Sauer, and John Stachel. It is planned to publish a volume based on the contributions to the conference, edited by Hubert Goenner, Jürgen Renn, James Ritter, and Tilman Sauer, in the Einstein Studies Series.
In the following section, the main research activities related to the emergence and the impact of the general theory of relativity are outlined: a) the reconstruction of Einstein's discovery process; b) the history of alternative approaches to the problem of gravitation; and c) studies of the contexts of the establishment of general relativity.
a) the reconstruction of Einstein's discovery process
Einstein's path to general relativity essentially begins in the year 1907 with the formulation of the equivalence principle and ends in the fall of 1915 with the discovery of generally covariant field equations for gravitation. The theory of a static gravitational field, which he had developed on the basis of the equivalence principle, was completed in the spring of 1912. This static theory was based on a scalar field equation modeled after Newtonian physics. It was still formulated without making use of any mathematics more sophisticated than standard differential calculus. Only later in 1912 Einstein did realize the relevance of Gaussian surface theory and, still somewhat later, that of the absolute differential calculus of Ricci and Levi-Civita for his problem, identifying the metric tensor as representing the gravitational field.
The impact of this considerably more sophisticated mathematics on Einstein's thinking was crucial for the development of the theory. Fortunately, the reconstruction of this period can be based on a rich empirical basis. Apart from a number of rather explicit publications and a well-documented scientific correspondence, one particular research notebook dating from the years 1912-1913, the so-called Zürich Notebook, allows a direct analysis of Einstein's thinking at that time.
Following groundbreaking papers by John Stachel, John Norton, and a few other scholars, as well as previous work by the Arbeitsstelle Albert Einstein, the continued investigation and reconstruction of Einstein's discovery process has been the object of various research activities at the Institute in cooperation with the scholars of the Arbeitsstelle. A meticulous line-by-line analysis of the Zürich Notebook had led to the identification of two distinct heuristic strategies in this discovery process. This identification proved to be an important interpretative tool for the understanding of Einstein's search for gravitational field equations. One strategy was to take physical considerations derived from classical physics, such as energy-momentum conservation and the recovery of Newton's gravitational theory in a suitable limit, as the starting point; the other strategy was to begin from mathematical considerations concerning the covariance group of candidate field equations and then to attempt to find a consistent physical meaning for the mathematical objects under consideration. The reconstruction of the calculations in the notebook had shown in particular that, following this latter strategy, Einstein had already considered the correct field equations of 1915 (albeit in linearized approximation) in 1912, and had thus come within a hair's breadth of the final general theory of relativity. He failed to recognize the physical meaning of these equations, however, and turned to the alternative strategy. Tilman Sauer presented an account of Einstein's heuristic strategies and his near-discovery of the correct field equations at the Conference on the History of General Relativity.
The research on the notebook hence throws new light on the complex process of interaction between mathematical representation and the construction of physical meaning. In particular, the establishment and stabilization of the new physical concepts that emerged with general relativity required a considerable amount of elaboration of the mathematical formalism, going considerably beyond finding the correct field equation. Paradoxically, this state of elaboration itself had to be reached under the guidance of concepts and heuristic strategies which were themselves still rooted in classical physics. It is therefore not surprising that Einstein first published an "erroneous" field equation in 1913, which seemed satisfactory from the point of view of his heuristic strategies rooted in classical physics, and that it took him more than two years to return to the "correct" equation he had found but dismissed in 1912. In this time, he elaborated the consequences both of his "erroneous" field equation of 1913 as well as of the other candidate field equations he had also considered in his research notebook of 1912. It was only after this exhaustive elaboration of the possibilities, opened up by the available formalisms, that the network of physical and mathematical relationships thus established had become sufficiently dense to shape and stabilize the new concepts which finally allowed him to identify the correct field equation of general relativity. A discussion of the interplay between formalism, heuristics and the emergence and role of Einstein's heuristic double strategy, based on respective presentations at the Conference on the History of General Relativity, will be published in a joint paper by Jürgen Renn and Tilman Sauer. An extensive discussion of the conceptual presuppositions, mathematical knowledge and heuristic strategies was prepared jointly by Jürgen Renn and Tilman Sauer as an unpublished manuscript.
The detailed reconstruction of how Einstein discovered in 1915 that he had to give up the field equations of 1913 was one of the research topics on which Michel Janssen worked during his stay at the Institute, in collaboration with the members of the Arbeitsstelle Albert Einstein. In this respect, he combined work on the Zürich Notebook done at the Institute and work done for the editorial project of the Collected Papers of Albert Einstein in Boston on parts of the so-called Einstein-Besso manuscript dealing mainly with calculations of Mercury's perihelion shift on the basis of the "Entwurf" theory. The failure of the "Entwurf" theory to account for this anomaly of classical mechanics was one of the reasons for the demise of this theory. Another, more important aspect concerns one of the central heuristic principles leading Einstein in his search for gravitational field equations, which can be formulated as follows: it should be possible to interpret the inertial forces experienced in a rotating frame of reference as gravitational forces. Michel Janssen carried out a detailed reconstruction of how Einstein in 1915 suddenly discovered that he had been wrong for over two years in believing that his so-called "Entwurf" theory met this important requirement. This reconstruction was presented as part of the session dealing with the problem of formalism and heuristics at the Conference on the History of General Relativity and will be published under the title "Rotation as the Nemesis of Einstein's `Entwurf' Theory."
It is planned to publish the cumulative results of the reconstruction of Einstein's discovery process in a comprehensive monograph.
b) the history of alternative approaches to the problem of gravitation
Several research activities have been dedicated to the exploration of the theoretical contexts of Einstein's theory of general relativity, both in the sense of alternative approaches to the problem of gravitation before the advent of general relativity, and in the sense of the integration of general relativity into theoretical physics after its creation. The discussion of alternatives in the history of general relativity to Einstein's path helps to understand and distinguish between conceptual necessities and contingencies in the actual historical development. It is planned to publish the studies on this subject undertaken at the Institute in a forthcoming volume on alternative approaches to relativity and gravitation, to be edited by Julian Barbour and Jürgen Renn.
John Stachel has studied indications of alternate paths that the historical development might have taken, resulting in rather different developments of the theory of relativity. One such scenario was presented at the Conference of the History of General Relativity in a paper on "The Story of Newstein." The scenario starts from the observation that the mathematical concept of an affine connection, the appropriate expression for a single inertia-gravitational field as the basic element of any gravitational theory suggested by Einstein's crucial insight in the essential unity of gravitation and inertia, was only formulated after the general theory of relativity and in response to its development. Like Einstein, the mythical physicist Newstein, who worked sometime in the period between Newton and Einstein realizes the unity of gravitation and inertia but he does so on the basis of Newton's theory of gravitation. In contrast to Einstein, Newstein develops a four-dimensional version of Newton's theory of gravitation using the concept of an affine connection. The scenario discusses the consequences of the advent of special relativity for such a reformulated Newtonian theory of gravitation (which historically only appeared after general relativity). A published version of this presentation is in preparation.
Leo Corry has studied David Hilbert's work on relativity, and particularly his formulation of a generally relativistic field equation for gravitation, in the context of Hilbert's attempts to develop a unified axiomatic approach to the whole of physical science. One of the goals of Corry's research is to enlarge the view of the field of possible pathways which could lead to a theory such as general relativity.
The first year of his work on the project "Hilbert and General Relativity" was invested mainly in gathering sources and preparing a preliminary mapping of the territory to be covered, which was explained in last year's report. In the course of the past year, Leo Corry has been transforming that material into publishable form. One result is an account of Hilbert's work, both published and unpublished, on the axiomatization of physics in its various domains. This work is meant as a contribution to a general understanding of Hilbert's basic conceptions of the interrelations between physics and mathematics, as well as an assessment of his actual influence on the development of early twentieth-century physics. Hilbert's path to general relativity was investigated within the more general framework provided by the analysis mentioned above; this account is a more focused examination of the evolution of ideas leading to Hilbert's discovery of the field equations of general relativity. This analysis also provides a completely new perspective on the actual historical alternatives to Einstein's own path to general relativity.
The relationship between geometry and physics in the work of Hilbert has been another focus of Leo Corry's work. Hilbert's Grundlagen der Geometrie, published in 1900, had a pervasive influence on all branches of twentieth-century mathematics. The historical analysis based on the material gathered sheds new light on Hilbert's own conception of geometry as a branch of natural science. This analysis covers Hilbert's view throughout his career, from 1891 to 1930, and presents a new interpretation of the philosophy behind the Grundlagen.
Leo Corry's work will appear in various frameworks, among them the planned volume on alternative approaches, and the proceedings of a conference on geometry and physics in March 1996 at the Open University, Milton Keynes. Preliminary results of his work on Hilbert's path to general relativity were presented at the Conference on the History of General Relativity.
James Ritter investigated the role of general relativity within the research program on a unified field theory. He reported on the initial stages of his research in his contribution to the Conference on the History of General Relativity. Here he outlined the changes in the 1920's in the role unified field theories were seen to play in the eyes of those who worked on them, from a `natural' continuation of Einstein's own work on general relativity to that of an equally `natural' continuation of the program of the pioneers of quantum physics, particularly Dirac. This work will be included in the planned book based on the conference.
James Ritter has also tried to identify more exactly the nature and the chronological sequence of the stages in the development of Einstein's attitude towards the "unified field theories," which occupied the majority of his working life. He attempted to link the "internal" changes in the mathematical and epistemological concerns Einstein put forward with "external" events and constraints within the scientific community, such as the replacement of relativity by quantum physics as the center of interest among physicists and Einstein's growing tendency to address himself to and adopt the attitudes of the mathematicians he saw as a replacement group. These investigations are part of the research activities on alternative approaches to general relativity and gravity.
c) studies of the contexts of the establishment of general relativity
Two contexts of the establishment of general relativity are presently studied at the Institute: the academic context, meaning the integration of the theory into a teaching tradition; and the political context of its creation and reception.
Teaching constitutes an essential intermediate step in the process of the social mediation of scientific research results. While the processes underlying the development of the physical theory, which is documented by research notes and publications in scientific journals, forms one pole in the communication chain, the other pole is given by the mediation of research results in textbooks and popular expositions. The oral teaching tradition lies in between; in its early phase, the reflection on topical research problems and the constraints arising from the need to embed the new theory in the canon of scientific tradition are close to each other. Here one has the chance to study in detail the rise of a generally accepted "context of justification" from the individual "context of discovery" and to relate questions of the reconstruction of individual cognitive processes to questions of the social development of knowledge.
Einstein's early courses are a valuable source for the reconstruction of this academic context of the history of relativity theory. Tilman Sauer and Folkert Müller-Hoissen are preparing editions of student lecture notes from Einstein's courses for which his original notes are not preserved. Present work concentrates on a course on general relativity probably held in the summer semester 1919 at the University of Berlin. For this course there are notes from Hans Reichenbach preserved in the Reichenbach archives in Pittsburgh.
Einstein did not give an axiomatic introduction to the theory of general relativity in these lectures, but followed a course which very much parallels the actual historical development. He started by pointing out deficiencies of both the theory of special relativity and of classical mechanics, and discussed in particular those elements which had played a major role in the heuristics and had guided his search for a general theory of relativity. These include the local equivalence of gravity and inertia, application to homogeneous gravitational fields, and the rotating disc motivating the step towards non-Euclidean geometry. After this introduction, Einstein presented an extensive exposition of tensor calculus and applied this mathematical framework to achieve a manifestly covariant formulation of Maxwell's equations. Einstein proceeded to introduce the gravitational field equations and discussed their properties. Turning to the implications of the covariant field equations, he elaborated on the generalized energy conservation laws, on gravitational waves, the behavior of rods and clocks in a gravitational field, and planetary motion, including the shift of Mercury's perihelion. The lectures end with a discussion of problems at the "cutting edge" of research at the time, namely the "cosmological problem" and a modification of the field equation in order set up a theory of the electron, related to a paper he presented in April 1919 to the Prussian Academy of Science.
The Reichenbach notes are of historical interest not only for the development of Einstein's scientific ideas at that time; they also shed light on the genesis of Reichenbach's first publications on the philosophical aspects of Einstein's theory of relativity. Reichenbach's subsequent work on relativity, which was quite influential, played an important role in the transmission of the new theory to a wider audience.
Following up on earlier work by Tilman Sauer in the Arbeitsstelle Albert Einstein, Folkert Müller-Hoissen has been preparing the transcription of and commentary on the Reichenbach notes since November 1995. The aim is to edit a transcription of the notes, which will be accompanied by extensive editorial and historical comments and by brief reviews from the perspective of modern physics of central topics addressed in the manuscript. To date, about one-third of a preliminary transcription of the notes prepared by the Arbeitsstelle Albert Einstein has been revised and commented upon.
Einstein's fame after the confirmation of the bending of light in 1919, predicted by the relativity theory and generally taken as a proof for the validity of this theory, was a central reason for the intense reaction to him as a political figure in the public sphere as well as a physicist. By exaggerating Einstein's involvement in the peace movement during World War I, the pacifist organizations in the twenties also tried to profit from his fame for their own purposes. Understanding and assessing Einstein's historical role as a prominent public figure who simultaneously became a symbol of successful scientific creativity and of heated ideological dispute is at the center of an investigation by Hubert Goenner and Giuseppe Castagnetti from the Arbeitsstelle Albert Einstein. The aim is to place relativity theory and its creator Einstein in the social and cultural environment of the physics community. A first part of this work has been completed and led to a paper submitted for publication: "Albert Einstein as a Pacifist and Democrat during the First World War." It is planned to extend this work through an investigation of the relationship of Einstein with the Deutsche Liga für Menschenrechte during the Weimar Republic; preliminary archival studies as well as a collection of secondary literature have been completed.
The research on Einstein's political biography will be complemented by a study by Hubert Goenner and Britta Scheideler on Einstein's political behavior and thinking in the context of cultural and social change between 1914 and 1933. One focus of the study is Einstein's socialization through connections to intellectual and literary circles outside the scientific community. The importance of these connections in explaining his extraordinary reactions to World War I or to pacifism (compared to the majority of scientists) is a central point of interest. The study also focuses on the question of to what extent the affiliation with a particular social group was important for the political behavior of the members of the scientific community. The project therefore aims at a description of the scientific community as a more or less coherent social group, with a common social profile and status, self-understanding, intellectual tradition and internal communication network. The impact of these social structures on the scientists' political behavior is investigated by analyzing the autobiographical material of numerous physicists, mathematicians and chemists.
Giuseppe Castagnetti, Hubert Goenner, Dieter Hoffmann, Horst Kant, Alexei Kojevnikov, and Jürgen Renn
A collaborative study is being undertaken with the aim of reconstructing the reorganization of physical research as a reaction to the emergence of "quantum problems" early in the twentieth century, meaning the problems which contributed to a disintegration of classical physics and which were eventually recognized as pertaining to the entire range of quantum theory. The study's central interest is the question to which extent such a reorganization took place as a result of explicit reflections on the disintegration of classical physics.
The problems later recognized as quantum problems pertained to such different areas of research in classical science as black body radiation, spectroscopy, or solid state physics. Typically they were "borderline problems," in the sense explained in the introduction to Project 2, that is, located at the frontier between partially distinct conceptual frameworks of classical physics. The incompatibility of these problems with the foundations of classical physics and their mutual interrelationships were only gradually recognized. This process extended over a quarter of a century, roughly between 1900 and 1925, and involved a considerable number of physicists, chemists, and mathematicians from several countries. While the emergence of new theoretical concepts and new experimental results have been extensively studied by historians of science, the processes of knowledge integration underlying this development still require further study. The present focus of research concerns only one specific aspect of this integration: the effect of contemporary scientists' recognition of quantum problems and their interrelationships to the shifting of their research foci, reallocation of their resources, and reorganization of research structures and policies. In this way, the study seeks to answer the question of whether quantum theory was developed, like Einstein's theory of relativity, primarily by the individual contributions of a few distinguished scholars or, in contrast to Einstein's discovery, by the joint effort of a scientific community interacting according to principles also at work in modern research institutions. The study thus seeks to bridge the gap between work on individual physicists' paths of discovery and research on the institutional history of science.
The present research activities grew out of earlier work on Einstein as an organizer of science, pursued by Giuseppe Castagnetti and Hubert Goenner under the auspices of the Arbeitsstelle Albert Einstein, under the direction of Peter Damerow and Jürgen Renn at the Max Planck Institute for Human Development and Education. This earlier research indicated that Einstein's call to the Kaiser-Wilhelm-Institut für Physik in Berlin has to be seen in the context of systematic attempts by science policy makers to create the institutional conditions for developing the early quantum ideas into a new theory of matter, based on an integration of physical and chemical knowledge. An understanding of the overall role of such attempts at a goal-oriented science policy for the actual creation of quantum mechanics, requires, however, a larger, comparative study involving the most significant institutional centers concerned with research on the quantum problems.
Present activities concentrate on four of the major sites of exploration of quantum theory, homes of some of the most powerful and successful physicists, and organizers of the work toward the elucidation of quantum problems: Berlin, Munich, Göttingen and Copenhagen. For each of these locations, the various social and cognitive processes behind the shift that put the quantum at the center of research activities are investigated. For instance: how were dissertation topics assigned; how did quantum physics figure in attempts to gain additional funds from ministries of education and culture; what were the selection criteria for appointments at or invitations to these different centers; how did the work of theorists and experimentalists (e.g. spectroscopists) become more closely linked as a result of the reaction to the quantum problems?
Work on this study started in late 1995. Preliminary archival work was performed in the Sommerfeld Archive in Munich by Horst Kant and in the Niels Bohr Archive in Copenhagen by Alexei Kojevnikov. Edward Jurkowitz and Jürgen Renn began to work on a concise history of the major developmental steps of quantum theory for the purposes of this study. Giuseppe Castagnetti and Hubert Goenner continued their work on the role of Albert Einstein and the Kaiser-Wilhelm-Institut für Physik for the development of quantum physics; a preliminary version of their contribution was presented at the "Fourth International Conference on the History of General Relativity" in Berlin. It is planned to publish the results of the joint work in an edited book.
In the period extending roughly from the early 1930's to the 1960's, the neo-Darwinian paradigm, founded by scholars like R. A. Fisher, S. Wright, T. Dobzhansky, and E. Mayr, seemed to provide an all-embracing, monolithic framework of evolutionary biological thought. By approximately 1970 this paradigm had been replaced or complemented by a number of new approaches to evolution which called even the most fundamental concepts of the previous period into question. There are no longer unequivocal definitions of "adaptation," "gene," "species," or, in fact, "Darwinism."
While evolutionary biology can no longer be viewed as a unified field of knowledge, its foundational concepts, such as the concept of the gene, nevertheless still play a role for knowledge integration in biology - relating insights in molecular biology to knowledge in population genetics, for example. We are thus confronted with a protracted, still open-ended scientific revolution. Analyzing the implications of this integrative function of the foundational concepts of evolutionary biology is one of the central objectives of the study pursued by Peter J. Beurton. His present research, which builds on his previous work on the history and structure of the synthetic theory of biological evolution as well as on his investigations into the biological species concept, concentrates on the concept of the gene.
Peter J. Beurton, Wolfgang Lefèvre, and Hans-Jörg Rheinberger have organized an international working group to investigate the historical development of this concept. A first workshop of this group was held in 1995; its discussions took two position papers on the present status of the gene concept by Peter J. Beurton and Hans-Jörg Rheinberger as their starting point (see the preprint based on this workshop). A second workshop on this topic, aimed at preparing a book manuscript, is scheduled for the fall of this year (see "Planned Workshops and Conferences").
As a more encompassing activity, Peter J. Beurton has begun with the construction of a database for conceptual problems in evolutionary biology which builds on a core collection of 2500 papers deposited at the Institute (at present 3000 entries).
Jürgen Renn (responsible), in co-operation with Michele Camerota, Peter Damerow, Gerd Graßhoff, Simone Rieger, Bernd Wischnewski, and Michael Schüring
Recent developments in electronic data processing have fundamentally changed the potential of research in the history of science, as in other historical disciplines. Although the new possibilities are still realized only to a limited extent, they already offer important new research methods.
On the one hand, the electronic storage of historical sources improves their accessibility and makes new and powerful methods of the retrieval of information possible. In the past, documenting, interpreting, and publishing of new sources was a major focus of the work of historians. The electronic storage of sources offers improved methods of searching and combining information to such an extent that problems of integrating historical details into coherent models of historical developments turn out to become increasingly more important. In the special case of the history of science, electronic data storage and retrieval challenges the traditional picture of the history of science as a history of accumulating knowledge, and possibly offers for the first time an opportunity to reconstruct not only the history of representations of knowledge, but also the development of knowledge structures themselves. On the other hand, electronic data processing also provides new methods for constructing models of mental structures and activities. Thus, by means of computer models, the traditional methods of history of science for reconstructing discovery processes can be complemented by computer simulations of such processes under different conditions and compared to the results from historical case studies.
Even though preparing electronic editions of historical sources and constructing computer models of mental processes are not at the center of activities at the Institute, the new opportunities offered by electronic data processing are used as far as possible with the available resources:
Peter Damerow and Bernd Wischnewski
In order to facilitate the analysis of electronically accessible sources, a toolbox has been developed that makes it possible to create specific working environments to assist various types of analysis of textual data in a very short time. A general format for structuring text data has been defined in order to make it possible to identify and access text units by keys. High performance programs have been written to handle substantial bodies of textual data formatted in this way. These programs are used as externals to a commercial hypertext system (HyperCard), thus combining the flexibility of the high-level programming techniques within this system with the power of specialized programs for basic transformations of the textual data.
The basic functions of the toolbox consist of instant retrieval and editing of specific text units, retrieval of images of corresponding manuscript pages, framing of parts of images of manuscript pages, editing of hypertext links between text units and image frames, and text indexing. Working environments created by this toolbox have been applied for various purposes in different project activities. The toolbox is developing continuously, according to the requirements of ongoing research projects.
Michele Camerota, Peter Damerow, Simone Rieger, Jürgen Renn, and Bernd Wischnewski (Max Planck Institute for the History of Science), Paolo Galluzzi (Istituto e Museo di Storia della Scienza, Florence), Isabella Trucci (Biblioteca Nazionale Centrale, Florence)
Galileo's notes on motion and mechanics, kept as Ms. 72 in the Galilean collection of the Biblioteca Nazionale Centrale in Florence, document his work on mechanical problems over a period of more than 40 years. During this time, his thinking developed from its scholastic beginnings to the publication of the Discorsi e dimostrazioni intorno a due nuove scienze (1638), the last of Galileo's works and one of the most important chapters in the history of the emergence of classical mechanics. The manuscript consists of more than 300 pages. They contain numerous short texts in Latin and Italian, representing sketches of proofs, but also extended drafts intended for publication, calculations, tables of calculated numbers, diagrams, and even some documents pertaining to experiments performed by Galileo. These fragments are of special interest, since they provide valuable clues for the reconstruction of the development of Galileo's ideas on motion and mechanics in all stages of his long scientific career.
For this reason, historians of science have paid increasing attention to manuscript 72 in the last decades. The manuscript is considered the essential source of information on the intellectual route followed by Galileo in achieving the insights he submitted in the Discorsi. However, in spite of many important recent contributions by scholars such as Drake, Galluzzi, Naylor and Wisan (as well as of the pioneering work by Raffaello Caverni, at the turn of the century), a comprehensive reconstruction of the conceptual and deductive structures shaping the path of development of Galileo's ideas has not yet been accomplished.
The Istituto e Museo di Storia della Scienza and the Biblioteca Nazionale Centrale in Florence, in close collaboration with the Max Planck Institute for the History of Science, have launched a project to create an electronic edition of the manuscript. The first stage of the work has now been completed. Using electronic tools developed at the Institute, a carefully-controlled transcription of the texts related to motion (folios 33-194), encompassing a mark-up of the text indicating emendations, deletions, marginal notes, and insertions has been prepared. The relation of the transcription to digital images of the manuscript pages has been documented by means of frames and hypertext links, the diagrams of the manuscript redrawn, and a preliminary transcription of the calculations prepared. Further work has also been done to provide a precise physical description of the manuscript.
In order to make the results of the editorial work accessible on different computer platforms, programs have been developed for converting the data into a standardized format. The format which will be used is the HTML format of the World Wide Web, so that any web browser will be able to retrieve the complex structure of the electronic edition.
An English translation of the texts is currently being prepared and deductive structures in the manuscript and their relations to published proofs in the Discorsi are being analyzed. The next step of the project will be to accomplish a critical apparatus for texts and calculations and a paleographic analysis of each single folio of the manuscript. A careful search of Galileo's correspondence for clues connected with the evolution of Galileo's investigations on motion is also in progress.
The result of the systematic analysis of the material will be compared with arguments in ancient and medieval text on the same subject, with experiences documented in the contemporary technical literature, and with the outcome of modern experiments and the structures of modern proofs.
Peter Damerow and Michael Schüring (Max Planck Institute for the History of Science), Robert Englund and Hans Nissen (Freie Universität Berlin), Martin Schreiber and Martin Warnke (Universität Lüneburg)
Documents that give evidence of the development of mathematical thinking in ancient civilizations provide an important source for studying the emergence of formal thinking. In order to make such documents more easily accessible, a technique has been developed to present such data (consisting of catalogues, transcriptions, images - photos and drawings - and indices) in a standard format that is accessible independent of the computer system used. The development of such a technique of representation has been made possible by the success of the Internet, which not only fostered the introduction of de-facto standards of data representation (HTML for multimedia hypertexts, JPG scanned grayscale and color images, etc.), but also initiated the development of powerful software tools for the retrieval of correspondingly formatted data.
As a first application of this technique, in co-operation with the editors of the proto-cuneiform tablets of ancient Mesopotamia, a project aiming at making these texts accessible has been launched. A prototype of the representation of the data in HTML format for retrieval from CD-ROM or from an internet server has been developed, which encompasses access to different types of data. A catalogue of the texts contains detailed archaeological information as well as information about the present owner of each text, related publications, and interpretations. The texts themselves are represented by photos and by drawings, both in natural size and enlarged four times. Furthermore, transcriptions are provided for each text. The texts are accessible both from an alphabetically arranged list of excavation numbers and from a sign list via a glossary with references to all texts containing the signs in question. Access through a classification of the texts according to their contents will be added later.
Currently, programs are being developed to automatically generate systems corresponding to this prototype from the original image and text data. The complete archive, containing the photos of the texts, has already been scanned (about 8000 photos) and converted into the required file format. Work is in progress to convert about 4000 drawings in postscript format produced by computer graphics into the required file format.
Several types of astronomical texts attest to the earliest elaborate form of astronomy, which flourished in the first millennium B.C. in Ancient Mesopotamia.
Early astronomy dealt with events such as eclipses and the observation of the first and last visibility of the moon, planets and stars after (or before) their close proximity to the sun prevented them from being seen. The Babylonian theories could accurately predict these events. Their basic parameters are of such good quality that they merged into Greek astronomy and continued to be the backbone of astronomical knowledge up to the time of Kepler. Although we have a clear picture of the precision and predictive scope of Babylonian astronomical theories, their empirical basis has remained unclear. Which types of observations provided the information necessary to construe those theories? All information points to a different epistemological relation between observation and theory in prehistoric astronomy.
The recently published Astronomical Diaries are a collection of astronomical cuneiform texts in Akkadian, which was the language used for Babylonian astronomy during the first millennium. These texts report a variety of astronomical events over a certain period, including eclipses and the visibility phenomena of the moon and planets. Despite a careful analysis of possibly false assumptions, all previous reconstructions failed to provide a consistent interpretation of the Diaries as observational reports.
New forms of computer representations of the Akkadian texts and a systematic hermeneutic search for a consistent interpretation have been developed, and all texts are now represented as linguistic Akkadian tokens. According to a trial interpretation of the astronomical language, these sentences can be automatically translated into corresponding observational scenarios. A highly accurate recalculation of the historical sky over Babylon then allows a comprehensive test of the validity of numerous interpretation models in reference to all known cuneiform tablets of that type. With these methods, it could be established that the observational reports of the Diaries are indeed coordinate measurements suitable to found Babylonian theoretical astronomy and play a specific role in the formation of one of the earliest scientific theories.
The formation of scientific theories is a paradigmatic case of creative problem solving. The methods scientists use for constructing new scientific hypotheses are determined by examining case studies from various fields and historical periods, and methods of discovery are investigated in different scientific contexts and methodological situations.
A wide spectrum of historical cases has been examined: the discovery of the urea cycle in 1932 by Hans Krebs, several case studies from early twentieth-century physics, and the controversy about "cold fusion." The domain-specific methods vary; yet we see a (rather unexpected) common stock of methodological principles. It contains general heuristics for model formation and rules for generating and evaluating causal hypotheses.
The set of cognitive components relevant for the discovery process form an epistemic system. It contains epistemic goals, rules of action commonly known as heuristics, and convictions of the involved scientists. Since an epistemic system is a highly complex interaction of knowledge components, heuristics, and scientific actions, it proved fruitful to model its behavior on a computer. For that purpose, a representation language called Epilog (Epistemic Systems in Prolog) has been developed which has a graphical user interface that makes semantic structures and model behavior transparent.
The adequacy of a model is decided by comparing the steps taken by the model with experiments documented in laboratory notebooks or original publications. In the case of the discovery of the urea cycle by Hans Krebs and Kurt Henseleit in the early thirties, the computer model has successfully reproduced the sequence of experiments as recorded in their laboratory notebooks.