§103

As the indifference of my contemporaries could in no way shake my conviction in the truth and importance of my theory of colour, I twice edited and published it, in German in the year 1816 and in Latin in the year 1830 in the third volume of J. Radius’ Scriptores ophthalmologici minores. Nevertheless, the complete lack of response leaves me with little hope at my advanced age of experiencing a second edition of these essays, and so I shall set forth here the few ideas that I still have to add to the subject.

Whoever undertakes to discover the cause for a given effect will, if he approaches his work thoughtfully, begin by thoroughly investigating the effect itself, since the data for discovery of the cause can only be collected from it, and it alone provides the direction and the guiding thread to the discovery of the cause. Yet none of those who proposed theories of colour before me did this. Not only did Newton go in search of the cause without having any precise knowledge of the effect to be explained, but also his predecessors did it in this manner. Even Goethe, who to be sure investigated and discussed the effect, the given phenomenon, and so the sensation in the eye far more than others, did not yet go far enough in this, since otherwise he would have had to arrive at my truths, which are the root of all theory of colour and contain the grounds of his own. And so I cannot except him when I say that all before me, from the most ancient to recent times, were concerned only with researching which modifications either the surface of a body or light would have to undergo, whether through analysis into its components or through turbidity or other darkening, in order to show colour, i.e., in order to stimulate in our eye that characteristic and specific sensation that cannot be defined at all but only detected by the senses. Instead, obviously the methodical and correct way is first of all to turn to this sensation in order to see whether one could find out what is taking place in it physiologically according to its closer nature and the conformity to law of its phenomena.