The importance which Goethe himself saw in this aspect of the optical problem is shown by the place he gave it in the didactic part of his Farbenlehre. The first three chapters, after the Introduction, are called 'Physiological Colours', 'Physical Colours', and 'Chemical Colours'. In the first chapter, Goethe summarizes a group of phenomena which science calls 'subjective' colours, since their origin is traced to events within the organ of sight. The next chapter deals with an actual physics of colour - that is, with the appearance of colours in external space as a result of the refraction, diffraction and polarization of light. The third chapter treats of material colours in relation to chemical and other influences. After two chapters which need not concern us here comes the sixth and last chapter, entitled 'Physical-Moral Effect of Colour' ('Sinnlich-sittliche Wirkung der Farben'), which crowns the whole. There, for the first time in the history of modern science, a bridge is built between Physics, Aesthetics and Ethics. We remember it was with this aim in view that Goethe had embarked upon his search for the solution of the problem of colour. In this chapter the experiencing of the various colours and their interplay through the human soul is treated in many aspects, and Goethe is able to show that what arises in man's consciousness as qualitative colour-experience is nothing but a direct 'becoming-inward' of what is manifested to the 'reader's' eye and mind as the objective nature of colours. So, in one realm of the sense-world, Goethe succeeded in closing the abyss which divides existence and consciousness, so long as the latter is restricted to a mere onlooker-relationship towards the sense-world. If we ask what induced Goethe to treat the physiological colours before the physical colours, thus deviating so radically from the order customary in science, we shall find the answer in a passage from the Introduction to his Entwurf. Goethe, in giving his views on the connexion between light and the eye, says: 'The eye owes its existence to light. Out of indifferent auxiliary animal organs the light calls forth an organ for itself, similar to its own nature; thus the eye is formed by the light, for the light, so that the inner light can meet the outer.' In a verse, which reproduces in poetic form a thought originally expressed by Plotinus, Goethe sums up his idea of the creative connexion between eye and light as follows: ' Unless our eyes had something of the sun, How could we ever look upon the light? Unless there lived within us God's own might, How could the Godlike give us ecstasy?1 (Trans. Stawell-Dickinson)