THOMAS YOUNG, QUAKER SCIENTIST by GENEVIEVE MATHIESON Submitted in partial fulfillment of the requirements For the degree of Master of Arts Thesis Advisor: Dr. Gillian Weiss Department of History CASE WESTERN RESERVE UNIVERSITY January, 2008 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of ______________________________________________________ candidate for the ________________________________degree *. (signed)_______________________________________________ (chair of the committee) ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ (date) _______________________ *We also certify that written approval has been obtained for any proprietary material contained therein. ii Table of Contents Acknowledgements............................................................................................................iii Abstract.............................................................................................................................. iv I. Introduction ..................................................................................................................... 1 II. The Life and Work of Thomas Young........................................................................... 3 Childhood and Education as a Quaker............................................................................ 3 Medical School and Young’s First Publication .............................................................. 7 Quakers and University................................................................................................... 9 Pursuing a Medical Career............................................................................................ 11 Disownment .................................................................................................................. 13 Early Optical Experiments............................................................................................ 16 The Royal Institution & Maturation of Young’s Optical Theories............................... 21 Leaving the Royal Institution........................................................................................ 27 Conflict with The Edinburgh Review............................................................................ 28 Medical Practice and Egyptology ................................................................................. 31 Revisiting Optics........................................................................................................... 34 Young as Bureaucrat..................................................................................................... 37 Young’s Later Life........................................................................................................ 41 III. Conclusions................................................................................................................. 43 Impediments to Young’s Optical Theories................................................................... 43 The Mathematical and Scientific Styles of the English and the French ....................... 48 Quaker Science and Quaker Schooling......................................................................... 50 Quakers in the Royal Society........................................................................................ 53 Young As Quaker Scientist........................................................................................... 56 Bibliography ..................................................................................................................... 60 iii Acknowledgements Firstly, I would like to thank the members of my committee for working with me during this endeavor. I am particularly grateful to Gillian Weiss and Alan Rocke for their involvement from the beginning. Without their support, suggestions, and assistance, this thesis would not exist. I remain grateful to all of my friends and family for their ongoing encouragement of and interest in my academic progress as well as for providing reminders that there is life outside of school. I don’t have enough space to thank each of them individually, but I must offer particular thanks to my parents for their confidence in me, to Angie and Brent Robinson for being enthusiastic early readers and to Mindy Miller for research assistance and cheerleading above and beyond the call of duty. Finally, I would like to thank my husband Jim for providing countless meals and constant moral support, for being a willing reader of drafts and for his unfaltering belief in my ability to see this project through. iv Thomas Young, Quaker Scientist Abstract by GENEVIEVE MATHIESON Thomas Young was a widely accomplished polymath who discovered the principle of interference of light. This was just one of his achievements, made in the midst of practicing medicine, working as both a professional scientist and bureaucrat, deciphering portions of the Rosetta stone, determining the causes of color vision, and writing prolifically on all of these topics. The interference of light was later shown by Fresnel to be conclusive proof that light was vibratory rather than corpuscular. Given Young’s strong support for vibratory theory, this thesis seeks to determine why Young did not pursue his optical theories further. Through study of Young’s Quaker upbringing, an analysis of Quaker schooling and scientific practice, Young’s work and its reception by his scientific peers, I argue that Young’s scientific practice was inextricably linked with his Quaker background. 1 I. Introduction Thomas Young was a polymath, a talented physician – though lacking in bedside manner – a natural philosopher, a linguist, and a bureaucrat. Throughout his life he varied roles so frequently, he could almost be charged with dilettantism. Nevertheless, Young’s accomplishments ranged widely. In physical optics, he discovered the principle of interference of light, explaining diffraction phenomena and supporting the vibratory or wave theory. In physiological optics, he was the first to suggest the existence of single- color receptors in the eye and is credited with discovering the causes of color vision and color blindness.1 He defined the modulus of elasticity (now labeled Young’s Modulus) as the ability of a material to withstand length changes due to compression or extension. He published a comprehensive treatise on consumptive diseases that was inspired by his own experience with tuberculosis, and a survey course of medical lectures. Young attempted to decipher the Rosetta Stone and was able to complete a version of the demotic text before Champollion completed his own decipherment of the hieroglyphics. Young’s industry was astounding; in addition to his scientific and linguistic research and publications, he also maintained a career as a physician and bureaucrat. Young was an ambitious man, but one who retained a strict adherence to honesty, extended to the point of tactlessness. He refused to soften a harsh truth and tended to assume that his audience was his intellectual equal, traits that explain both his failure as a Royal Institution lecturer and his only modest success as a physician. Young was born a Quaker, a Christian sect that rejected worldly goods and maintained a strict sense of morality. His parents were of modest means, but his great-uncle Richard Brocklesby’s 1 Thomas Young, “The Bakerian Lecture: On the Theory of Light and Colors.” Philosophical Transactions 92 (1802): 21. The theory is now called the Young-Helmholtz trichromatic theory, and refers to the cones in the eye. 2 social status and his grandfather’s insistence on a classical education gave Young the schooling and connections necessary to travel in rarified circles. His membership in the Royal Society connected him politically, his profession as physician provided him considerable income, and both combined with his intelligence to yield countless opportunities for research and publication. Despite Young’s widespread achievements, however, he did not always take his projects to completion. Although Young discovered the principle of interference of light and addressed a few interesting cases of diffraction, he demonstrated it only for two rays or sources of light and failed to apply it more widely to optics. As a proponent of the vibration or wave theory of light, Young also tried to use the principle of interference as proof of light’s vibratory nature. While Young lived to see his vibratory theory of light vindicated, he did not shift the paradigm himself. Given his brilliance and scientific ability, it is curious that Young himself was not able to take his discovery past simple demonstration and to its broadest application. In this paper I contend that Thomas Young’s early religious background was influential in forming his personality and character, and subsequently his scientific style. This paper, therefore, is an investigation of that relationship. By portraying Young’s life and work in a holistic fashion, I intend to demonstrate that Young’s scientific practice was inextricably linked to his Quaker upbringing. 3 II. The Life and Work of Thomas Young Childhood and Education as a Quaker Thomas Young was born in 1773 in Milverton, Somerset, to Sarah and Thomas Young. He was the eldest of ten children but spent little time in the company