By means of these observations we realize that the third type of force, in so far as it is active in man, has the capacity, by co-ordinating the physical and etheric parts of the organism in one way or another, to promote happenings either of a more corporeal or a more psychical nature - namely, motion at one pole, sensation at the other, and feeling in the middle between them.¹ Remembering Goethe's formula, 'colours are deeds and sufferings of light', we realize how deeply true the concepts were to which he was led by his way of developing observation and thought.