The reason why Goethe chose optics as the field of conflict, and devoted to it more than twenty years of research and reflexion, amidst all the other labours of his rich life, lay certainly in his individual temperament - 'zum Sehen geboren, zum Schauen bestellt'.1 At the same time one must see here a definite guidance of humanity. Since the hour had struck for mankind to take the first step towards overcoming the world-conception of the one-eyed, colour-blind onlooker, what step could have been more appropriate than this of Goethe's, when he raised the eye's capacity for seeing colours to the rank of an instrument of scientific cognition?
In point of fact, the essential difference between Goethe's theory of colour and the theory which has prevailed in science (despite all modifications) since Newton's day, lies in this: While the theory of Newton and his successors was based on excluding the colour-seeing faculty of the eye, Goethe founded his theory on the eye's experience of colour.
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In view of the present scientific conception of the effect which a prismatic piece of a transparent medium has on light passing through it, Goethe's objection to Newton's interpretation and the conclusions drawn from it seems by no means as heretical as it did in Goethe's own time and for a hundred years afterwards. For, as Lord Rayleigh and others have shown, the facts responsible for the coming into being of the spectral colours, when these are produced by a diffraction grating, invalidate Newton's idea that the optical apparatus serves to reveal colours which are inherent in the original light. Today it is known that these colours are an outcome of the interference of the apparatus (whether prism or grating) with the light. Thus we find Professor R. W. Wood, in the opening chapter of his Physical Optics, after having described the historical significance of Newton's conception of the relation between light and colour, saying: 'Curiously enough, this discovery, which we are taking as marking the beginning of a definite knowledge about light, is one which we shall demolish in the last chapter of this book,2 for our present ideas regarding the action of the prism more nearly resemble the idea held previous to Newton's classical experiments. We now believe that the prism actually manufactures the coloured light.'
We find ourselves faced here with an instance of the problem, 'Discovery or Manufacture?' dealt with by Eddington in the manner described in our previous chapter. This very instance is indeed used by Eddington himself as a case in which the answer is definitely in favour of 'manufacture'. Nevertheless, Eddington complains, experts, in spite of knowing better, keep to the traditional way of speaking about the spectral colours as being originally contained in the light. 'Such is the glamour of a historical experiment.'3 It is for the same reason that Goethe's discovery continues to be unrecognized by the majority of scientists, who prefer, instead of examining the question for themselves, to join in the traditional assertion that 'Goethe never understood Newton'.
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As Goethe relates at the conclusion of the 'historical' part of his Farbenlehre,4 he was drawn to study colour by his wish to gain some knowledge of the objective laws of aesthetics. He felt too close to poetry to be able to study it with sufficient detachment, so he turned to painting - an art with which he felt sufficiently familiar without being connected with it creatively - hoping that if he could discover the laws of one art they would prove applicable to others.
His visit to Italy, a land rich both in natural colour and in works of art, gave him a welcome opportunity to pursue this inquiry, but for a long time he made no headway. The paintings he saw suggested no inherent law in their arrangement of colours, nor could the painters he questioned tell him of one. The only qualitative distinction they seemed to recognize was between 'cold' and 'warm' colours.
His own observations led him to a definite experience of the quality of the colour blue, for which he coined the phrase 'feebleness of blue' ('Ohnmacht des Blau'). In some way this colour seemed to him to be related to black. In order to rouse his artist friends and to stimulate their reflexions, he liked to indulge in paradoxes, as when he asserted that blue was not a colour at all. He found, however, as time went on, that in this way he came no nearer his goal.
Although the splendour of colour in the Italian sky and the Italian landscape made a powerful impression on Goethe, he found not enough opportunity for systematic study to allow him to arrive at more than a dim surmise of some law underlying the occurrence of colour in nature. Still, there was one thing he took home with him as a result of his labours. He had grown convinced that 'the first approach to colours as physical phenomena had to be sought from the side of their occurrence in nature, if one would gain an understanding of them in relation to art'.