4The Goethe tradition: the phenomenological approach
4.1 Phenomenological analysis may reveal underlying material processes
The almost complete lack of knowledge about colour processing in the visual pathway is quite understandable. How could it be possible to obtain such information without microelectrodes or other advanced instruments at hand to monitor the processing?
Aningeniouswayoutofthisapparentlyinsurmountabledifficulty was offered by Hering (1878). He held that there were actually two quite different routes to understanding the processes underlying colour vision: a direct physiological approach and an indirect psychological approach. The psychological approach was based on the presumption that information about material processes underlying colour vision may be obtained by analyzing the phenomenological characteristics of colour sensations. Actually, Hering accepted the psychophysical maxim of Mach (1865, p. 320) that made three basic assumptions:
1. Every mental process is unalterably correlated with an underlying material process.
2. Similar and different mental processes are, respectively, correlated with similar and different material processes.
3. Every detail in the mental process corresponds to a detail in the material process.
As may be seen, the maxim of Mach is a specification ofSpinoza’s principle of psychophysical parallelism. It may also be noted that the maxim is akin to Leibniz’s presumption that there is a pre-established conformity between mind and body (e.g. Boring, 1957, pp. 165–168).
Presupposing Mach’s maxim to be valid, it would be a straightforward undertaking to obtain information about material processes
42development of the basic ideas of the duplicity theory
underlying colour sensation, once an unbiased and comprehensive phenomenological analysis of colour vision was worked out. By following this lead, Hering (1878) obtained strong evidence of opponent interactions between colour-related material processes and thereby challenged the basic assumption of the Newton tradition that no interaction between colour processes occurs in the visual pathway.
4.2 The colour theory of J. W. von Goethe
Goethe (1810) had made a strong case for the phenomenological approach prior to Hering. Indeed, he had stressed the importance of a phenomenological analysis in its own right.
Apparently strongly influenced by the three leading German philosophers in the post-Kantian period, J. G. Fichte, F. W. J. von Schelling and G. W. F. Hegel, Goethe presumed that colour was an elementary phenomenon of nature that should be viewed in relation to other analogous phenomena like magnetism and electricity with the ultimate aim of uncovering the general laws of nature. He insisted that colour sensations should not be reduced to physiological processes, nor should they be represented by elementary, independent, physical units as Newton had done, but be regarded as phenomena in dynamic interactions with each other.
In order to obtain an adequate understanding of the basic processes governing colour appearance, he suggested that the whole range of colour phenomena should be explored, not just the very limited range investigated by Newton. He obtained an overview of the great variety of colour phenomena by dividing them into three different domains: colour phenomena primarily conditioned by (1) the visual system (e.g. afterimages), (2) colourless media (e.g. colours conditioned by prisms or clouds), and (3) properties of coloured objects (e.g. colours of the human skin). By exploring colour phenomena in these three domains closely, it would be possible, he believed, to reveal their basic laws (Goethe, 1810, Didaktischer Teil, pp. 21–294).
At the most fundamental level, Goethe presumed that light and dark, or as he also expressed it, light and not light, were polar or
the goethe tradition: the phenomenological approach 43
opponent phenomena and the prerequisite for all colour sensations. The most primitive and least developed colours were thought to be white and black. They were opponent and generated by light and dark, respectively. At a more advanced stage of development, he assumed that yellow may emerge when light is changed as a result of an interaction with dark, while blue may arise when dark is changed by an interaction with light. This development may proceed to higher levels. Thus, the yellow and blue colours, which were also thought to be opponent phenomena, may interact to generate a green colour. In fact, when the polarity between the two is in equilibrium, only pure green is observed with no trace of the yellow and blue components. Moreover, by gradually darkening or condensing yellow or blue, each of them would change towards red to such a degree that red eventually would dominate the colour appearance . Finally, a mixture of red-yellow and red-blue in due proportions would create the most highly developed colour – a pure red, which
Red
Purple |
Orange |
Blue |
Yellow |
|
Green
Fig. 4.1 Goethe’s colour circle. The extremes of the diameter represent opponent colours. Note that the opponent colour of blue is orange and the opponent colour of yellow is purple.
44development of the basic ideas of the duplicity theory
Goethe termed ‘Purpur’ (Goethe, 1810, p. 228). Thus, in addition to the primitive white and black, Goethe acknowledged the development of six different basic colours and, of course, innumerable colours resulting from their combinations.
The colour theory of Goethe is best illustrated by his famouscolour circle as shown in Fig. 4.1.
Thus, Goethe, like Newton, presented the different colour qualities on the circumference of a circle. The green colour was located between yellow and blue, violet between blue and red, and orange between red and yellow (Goethe, 1810, p. 287). Also, by a rotating diameter in the circle, he could determine all opponent colours by the two extremes of the diameter. Yet, in the final analysis, Goethe reduced all the opponent colours to three basic ones: yellow and red-blue; blue and red-yellow; pure red (‘Purpur’) and green (Goethe, 1810, p. 258).
Goethe stressed that one should perform the basic experiments oneself in order to obtain an understanding of the fundamental laws of colour phenomena. A deeper understanding of the opponent character of colour phenomena, for instance, could be attained by experiments on successive contrast. Pre-stimulation with, for example, blue, yellow or green would generate, respectively, orange, violet and pure red (‘Purpur’) contrast colours when the eye was test stimulated with an achromatic, neutral light (Goethe, 1810, pp. 44–45).
Goethe also held that the basic laws governing the colour phenomena were, under most conditions, completely concealed by more superficial factors. The many factors that may influence the colour of the human skin, for instance, made it impossible to see the fundamental processes involved. Nevertheless, he held that careful observation of certain fundamental colour appearances within each of the three colour domains would lend support to his colour theory.
4.3 Goethe’s contribution
Of course, Goethe was aware of the fact that his colour theory was, to a great extent, a product of previous thinking. Thus, a concept of colour opponency had already, long ago been developed by Greek