How fundamental is Goethe’s fundamental phenomenon of colour?
In the Kolloquium of issue 83 of this journal, Florian Theilmann (Theilmann 2005) criticizes my article ‘Prismatic colours explained with Goethe’s funda mental phenomenon’ (Veugelers 2005). He brings up two objections to show that my arguments are ‘not convincing’ for him. In his concluding paragraph he even proposes that Goethe’s fundamental phenomenon might not be applicable at all to diffraction phenomena. But what use would Goethe’s fundamental phenomenon have if it would only be applicable to one kind of phenomenon, i.e. Rayleigh scattering? One could hardly call it a ‘fundamen tal’ phenomenon then. In the following I refute Theilmann’s objections and show that what I presented in my article is valid, and with it the scope of Goethe’s fundamental phenomenon.
Theilmann’s first argument touches upon the question what happens if the refraction experiment is done with coloured light. He states (emphasis by F.T.): ‘[…] what is not to be ignored is that how strongly the bottom is raised and what kind of coloured borders arise depends absolutely on the colour of lighting of the object viewed. If (more or less) spectrally defined lighting is used - for example a sodium vapour lamp - a sharp image without additional prismatic colours is obtained’. This argument can be dismissed very simply by asking: what colour would the sunset have if the sun were a sodium vapour lamp? What colour would the sky have? Seemingly Goethe’s fundamental phenomenon of colour would not apply in that case. Thus, rejecting my article with this argumentation means nothing less than rejecting Goethe’s funda mental phenomenon altogether. [...]