Goethe's objections to Newton's theory of light and colours are better than often acknowledged. You can accept the most important elements of these objections without disagreeing with Newton about light and colours. As I will argue, Goethe exposed a crucial weakness of Newton's methodological self-assessment. Newton believed that with the help of his prism experiments, he could prove that sunlight was composed of variously coloured rays of light. Goethe showed that this step from observation to theory is more problematic than (...) Newton wanted to admit. By insisting that the step to theory is not forced upon us by the phenomena, Goethe revealed our own free, creative contribution to theory construction. And Goethe's insight is surprisingly significant, because he correctly claimed that all of the results of Newton's prism experiments fit a theoretical alternative equally well. If this is correct, then by suggesting an alternative to a well-established physical theory, Goethe developed the problem of underdete... (shrink)

Did Goethe devise an empirically viable theory of classical ray optics? Or can we at least make use of his ideas to propose one? And if so, does this confront us with an intriguing case of theory underdetermination? In this paper, which is mainly a comment on the recent work of Olaf Müller, I shall address these three questions and argue for ‘no, yes, no’. This is in contrast to Müller, who has recently launched a vivid defense of Goethe-style ray (...) optics :569–573, 2015b; Z Philos Forsch 69:588–598, 2015c; Br J Hist Philos 24:322–346, 2016). Müller aims to give an almost positive answer to all three questions: ‘perhaps, yes, yes’. My overall line of argument will be that the rather restricted regime of classical geometrical optics of spectral colors allows at best for a weak form of transient theory underdetermination that, in turn and more straightforwardly, also allows for a structuralist reading in terms of two structurally equivalent formulations of one and the same theory. However, extending any of the rivaling models of ray optics other than Newton’s beyond the mentioned regime and embedding them into physics in total—especially in view of thermodynamics—leads to a contradiction. Hence, Newton’s theory is confirmed as the only consistent theoretical interpretation of ray optics. (shrink)