Durham E-Theses Hans Reichenbach: philosopher-engineer Mcadam, Roger Michael How to cite: Mcadam, Roger Michael (1992) Hans Reichenbach: philosopher-engineer, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/5763/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk Hans Reichenbachs Philosopher-Engineer by Roger Michael llcAdam submitted for the Degree of Master of Letters University of Durham 1992 A B S T R A C T This thesis relates Hans Reichenbach's philosophy of science both to his historical context and to his interest in the physical world. The thesis begins with a review of his life, and notes the most significant influences on him„ His early ambition to become an engineer stimulated in him an active interest in understanding physical things, and his enjoyment in disseminating what he knew entailed that he maintained a keen interest in contemporary ideas. By the age of twenty he had turned to philosophy to enhance his appreciation of science, and was influenced by Kant and the neo-Kantian interpretation through Ernst Cassirer. His subsequent work is concerned with providing philosophical explication of the? major innovations of twentieth century science, and particularly of the implications of Einstein's Theories of Relativity and of Quantum Mechanics. The thesis proceeds by summarising Kant's 3.nd Cassirer's writings on the philosophy of science before examining Einstein's theories. Subsequent chapters analyse Reichenbach's most significant publications in chronological order, namely The Theory of F^elativity and A Priori Knowledge (1920), The Philosophy of Space and Time (1923), Experience and F-'rediction (1938), Philosophic Foundations of Quantum Mechanics (1944), and The Direction of Time (1956). The chapter on Quantum Mechanics is introduced with a summary of the scientific concepts introduced prior to Reichenbach's writing about them. Although he demonstrates the shortcomings of Kant's philosophical justification, the objective Reichenbach set himself throughout his work was to identify the principles that regulate our empirical knowledge. Despite? his close friendship with Rudolf Carnap and Morits Schlick, he differentiated his Empiricism from Logical Positivism, and he refused to accept that Conventionalism could offer a satisfactory analysis of knowledge of the objective world. The final chapter summarises the impact of his writing and his major contribution to philosophy. Hans Re acheinbaclhs Phi iosopher-Engineer by Roger MSchaeB MciflidlaiPii Departnent of Philosophy Unauersity of Durham SubMitted for the Degree of Master of Letters January 1992 The copyright of this thesis rests with the author. No quotation from it should be published without his prior written consent and information derived from it should be acknowledged. 2 1 JUL 1992 Hans Reichenbach; Phi1osopher-Enqineer CONTENTS Introduction 1 Chapter 1 Reichenbach's Life and Early Influences 3 Chapter 2 Immanuel Kant and the Neo-Kantian Inheritance 24 Chapter 3 Einstein and his Theories of Relativity 45 Chapter 4 Reichenbach, Relativity, and Kant 58 Chapter 5 The Philosophy of Space and Time 78 Chapter 6 Reichenbach on Probability, and E>;perience and Prediction 105 Chapter 7 Quantum Mechanics 127 Chapter 8 The Direction of Time 143 Chapter 9 Concluding Remarks 163 Bibliographical references 166 Index of Names 171 Hans Reichenbachs Philosopher—Engineer INTRODUCTION The objective of this thesis is to trace the development of Hans Reichenbach'5 philosophy of science from his early influences and through his major publications. As a boy Reichenbach's ambitions centred on being an engineer, and his acquisitive search for knowledge was to reinforce his understanding of physicaxl things necessary to a practical engineer. As a student his interests extended into understanding the structure of scientific knowledge., and he became absorbed in Kant's philosophy. With his understanding of mathematics and physics in the early years of the twentieth century, he recognised the potential challenge offerred by Boltsmann's statistical methods to the established deterministic science based on Newtonian principles that had also served as Kant's basis of reference. His early philosophical work., therefore, centred on an attempt to reconcile Kant's writings with the challenge of twentieth century science. His later work reflects this reconciliation, although he can justly claim to have dev£?loped an epistemological method of Logical Empiricism that is influential in contemporary writings in the philosophy of sc ience„ Reichenbach's philosophical development ran parallel to the development of logical positivism, itself a reaction to the scholastic traditions of European philosophy at the end of the ninteenth century, and he was a close friend of two members of the Vienna Circle, - Moritz Schlick and Rudolf Carnap. His interest in science, and physics and mathematics in particular, led him to give particular attention to the two contemporary innovations of major import, - relativity and quantum mechanics. The first three chapters essentially provide the early context for Reichenbach's work, beginning in Chapter one with a summary of his life and early influences on him. The second chapter reviews the Kantian philosophical influence, and the third chapter examines the theories of Relativity which were the inspiration for his earliest publications. The next five chapters are devoted to an analysis of his major writings in the philosophy of science. Chapter four concerns his 1920 publication The Theory of Relativity and A Priori Knowledge which is F^eichenbach •'s attempt at direct reconciliation of Kant with Einstein's theories. Chapter five is devoted to his final publication concerned with the post-relativistic physics of space and time, - The Philosophy of Space and Time published in 1928. Chapter six relates to the work that gives the clearest exposition of his epistemology, namely Experience and Prediction 1 - published in 1938, but the chapter is introduced with a review of Reichenbach'&• interest in the application of probabilistic considerations to empirical events. Chapter seven is introduced with a review of the development of quantum mechanics, before pro c e e d i n g t o Philosophic Foundations of Quantum Mechanics publishejd in 1944. Finally, chapter eight is concerned with Reichenbach's posthumous publication The Direction of Time. The concluding ninth chapter is an overall review of the philosophical impact of Hans f^eichenbach. Chapter 1 REICHENBACH'S LIFE AND EARLY INFLUENCES Childhood and youth Hans Reichenbach's childhood was spent in comfortable circumstances in Hamburg. He was born on 26 September 1891 as the third in a faimily of five children. His father, Bruno, had a successful grain importing wholesale busine?5s in which he had immersed himself since the death of his own father vjhen he was twenty three. Bruno was born into a Jewish family but converted in his twenties to the Reformed Protestant Church which he saw as a fulfillment of his Jewishness. His early pre-occupation with working life, which had been a necessity on his father's death, prevented him adopting a scientific career, and this was a source of regret. Hans' mother, Selma, nee Menzel, was from a family whose Protestant heritage wasi traceable back to the Fceformation and an abbot Bernhard von Senden who was one of the founders of the Evangelical Reformed Church. The von Senden family had spawned generations of doctors, clergymen, and pharmacists, and Selma's own mother Wendelina von Senden, grew up in the von Senden Pharmacy in Emden in East Friesland before her marriage to a Construction Engineer - Hermann Mensel. Selma was passionately interested in music and before marrying Bruno she had been a schoolmistress. She generated a keen cultural, but supportive, family environment for her five children. The household was financially secure and there was a common £5ager awareness of contemporary cultural events during Hans' boyhood. The family members played musical instruments and attended concerts in Hamburg and they enjoyed avid discussion of contemporary works of literature by authors like Ibsen and Shaw, Hans' elder sister Maria was four years his senior; his brother Bernhard, with whom he' remained close in his younger years, was three years older; sister Wendelina was five years younger? and brother Hermann was seven years younger than Hans. Comments on Hans as a boy derive either from Bernhard or Wendelina, or from letters or recollections from Hans himself. Hans showed early aptitude in both his thirst for understanding and his practical abilities. His mother would turn to him to fix minor household repairs, and he adopted the role of tutor in scientific understanding to both his older brother and younger sister. Based on recollections it is difficult to establish the chronology of early development of Hans and his relationships vgith his siblings, but the record is of a lively and precocious boy, ijlive to the world and to his own ego. He developed with complete confidence in himself and his abilities, and when very young exhibited sharp turns of temper when prevented from pursuing his own course of action. Hans recognised this weakness in himself and as a schoolboy succeeded in imposing his will to curb his tantrums. This quickness of temper was a feature he shared with his father, but in appearance and motivation he had inherited the characteristics of the Wenz£?l family.