Goethe's theory of the constitution of colours of the spectrum has not proved to be an unsatisfactory theory, rather it really isn't a theory at all. Nothing can be predicted with it. It is, rather a vague schematic outline of the sort we find in James's psychology. Nor is there any experimentum crucis which could decide for or against the theory. Ludwig Wittgenstein, Remarks on Colour, paragraphs 70 Wikipedia