Here we find the eye producing, as usual, a contrast-colour from out of itself, as an after-image, even while its gaze is fixed on the same colour in the outer world. The heightened brilliance within the given field is due to the addition of the after-image colour to the external colour.

The eye with its affinity to light comes into being in the apparently dark space of the mother's womb. This points to the possession by the human organism of an 'inner' light which first forms the eye from within, in order that it may afterwards meet the light outside. It is this inner light that Goethe makes the starting-point of his investigations, and it is for this reason that he treats physiological colours before physical colours.

The process involved in adaptation now becomes comprehensible. The cause of the dazzling effect of light of normal intensity on an eye adapted to the dark, is that in such an eye the blood is in a state of rest, and this prevents it from exercising quickly enough the necessary counter-action to the influence of the light. A corresponding effect occurs when one suddenly exposes to darkness the eye adapted to light. One can easily observe what goes on then, if, after looking for a time at an undifferentiated light surface such as the evenly luminous sky, one covers the opened eyes with the hollowed hands. It will then be found that the space before the eyes is filled by a sort of white light, and by paying close attention one recognizes that it streams from the eyes out into the hollowed space. It may even be several minutes before the field of vision really appears black, that is, before the activity of the inner light in the choroid has so far died away that equilibrium prevails between the non-stimulated nerves and the non-stimulated blood.

The reader may wonder why this phenomenon is not immediately adduced as a decisive proof of the fallacy of the whole Newtonian theory of the relation of 'white' light to the various colours. Although it does in fact offer such a proof, we have good reason for not making this use of it here. Throughout this book it is never our intention to enter into a contest of explanations, or to defeat one explanation by another. How little this would help will be obvious if we realize that research was certainly not ignorant of the fact that the opposite colour arises even when the eye is not turned to a white surface. In spite of this, science did not feel its concept of white light as the sum of all the colours to be an error, since it has succeeded in 'explaining' this phenomenon too, and fitting it into the prevailing theory. To do so is in thorough accord with spectator-thinking. Our own concern, however, as in all earlier cases, is to replace this thinking with all its 'proofs' and 'explanations' by learning to read in the phenomena themselves. For no other purpose than this the following facts also are now brought forward.

Of fundamental significance as regards method is the way in which Goethe goes on from the passage quoted above to speak of the activity of the inner light: 'This immediate affinity between light and the eye will be denied by none; to consider them identical in substance is less easy to comprehend. It will be more intelligible to assert that a dormant light resides in the eye, and that this light can be excited by the slightest cause from within or from without. In darkness we can, by an effort of imagination, call up the brightest images; in dreams, objects appear to us as in broad daylight; if we are awake, the slightest external action of light is perceptible, and if the organ suffers a mechanical impact light and colours spring forth.'

With this insight into the twofold nature of the process of vision we are now able to describe more fully the negative after-image. Although in this case, as Goethe himself remarked, the ordinary explanation seems to suffice, yet in view of our later studies it may be well to bring forward here this wider conception.

Besides Rudolf Steiner's fundamental insight into the spiritual-physical nature of the growing human being, through which he laid the basis of a true art of education, he gave advice on many practical points. For example, he indicated how by the choice of a suitable colour environment one can bring a harmonizing influence to bear on extremes of temperament in little children. To-day it is a matter of practical experience that excitable children are quietened if they are surrounded with red or red-yellow colours, or wear clothes of these colours, whereas inactive, lethargic children are roused to inner movement if they are exposed to the influence of blue or blue-green colours.

What Goethe does here is nothing less than to follow the development of sight to where it has its true origin. Let us remember that a general source of illusion in the modern scientific picture of the world lies in the fact that the onlooker-consciousness accepts itself as a self-contained ready-made entity, instead of tracing itself genetically to the states of consciousness from which it has developed in the course of evolution. In reality, the consciousness kindled by outer sense-perception was preceded by a dreaming consciousness, and this by a sleeping consciousness, both for the individual and for humanity as a whole. So, too, outer vision by means of the physical apparatus of the eye was preceded by an inner vision. In dreams we still experience this inner vision; we use it in the activity of our picture-forming imagination; and it plays continuously upon the process of external sight. Why we fail to notice this when using our eye in the ordinary way, is because of that dazzling process mentioned earlier in this book. Goethe's constant endeavour was not to become the victim of this blindness - that is, not to be led by day-time experience to forget the night-side of human life. The passage quoted from the Introduction to his Farbenlehre shows how, in all that he strove for, he kept this goal in view.

On the basis of our present findings it is no longer enough to trace the appearing of the after-image solely to a differential fatigue in the retina. The fact is that as long as the eye is turned to the bright window-pane a more intensive blood-activity occurs in the portions of the eye's background met by the light than in those where the dark window-bar throws its shadow on the retina. If the eye so influenced is then directed to the faintly illumined wall of the room, the difference in the activity of the blood persists for some time. Hence in the parts of the eye adapted to darkness we experience the faint brightness as strongly luminous, even dazzling, whereas in the parts more adapted to light we feel the same degree of brightness to be dark. That the action of the inner light is responsible for the differences becomes clear if, while the negative after-image is still visible, we darken the eye with the hollowed hands. Then at once in the dark field of vision the positive facsimile of the window appears, woven by the activity of the blood which reproduces the outer reality.

This psychological reaction of children to colour is not surprising if one knows the role played by the blood in the process of seeing, and how differently the soul-life of man is connected with the blood-nerve polarity of his organism in childhood and in later life. What we have described as the polar interplay of blood and nerve in the act of sight is not confined to the narrow field of the eye. Just as the nerve processes arising in the retina are continued to the optic centre in the cerebrum, so must we look for the origin of the corresponding blood process not in the choroid itself, but in the lower regions of the organism. Wherever, therefore, the colour red influences the whole nerve system, the blood system as a whole answers with an activity of the metabolism corresponding to the contrasting colour, green. Similarly it reacts as a whole to a blue-violet affecting the nerve system, this time with a production corresponding to yellow-orange.