5 - The debate in Germany on the nature of light, 1740–95

Summary

Introduction

In the standard historiography of science the eighteenth century is the period in which the emission conception of light was quite generally accepted, certainly after 1740. Euler is usually mentioned as the exception to this rule. Surveys that are more oriented towards Germany add one or another dissident to the list but leave the image unaltered on the whole: The emission tradition ruled the physical optics roost in the eighteenth century. Apparently the picture of the situation in different countries is to a great extent determined by simply declaring the general picture to be valid for every country, without any thorough investigation of the matter. Britain and Ireland are the only countries on which detailed and systematic research has been carried out. G. N. Cantor has provided an exhaustive survey of optical viewpoints in this region. His results do, it is true, lend nuances to the established image, but they introduce no radical change. In Cantor's book only 9 per cent out of a total of sixty-nine optical theorists from the eighteenth century support a medium theory, while the remaining 91 per cent can be located within the emission tradition. In other words, the historical evidence thus far available confirms the strongly dominant position of the emission tradition in the eighteenth century. Nevertheless, it will be argued in this section that a substantially different view of the matter ought to be given for Germany.