Here is repeated in a special way the threefold organization of man, for the seeing of colour depends on an organic process apart from the nerve processes and similar to that which takes place between heart and lungs, whilst the seeing of forms and spatial vision depend upon certain movements of the eyeball (quick traversing of the outline of the viewed object with the line of sight, alteration of the angle between the two axes of sight according to distance), in which the eye is active as a sort of outer limb of the body, an activity which enters our consciousness as little as does that of our limbs. It now becomes clear that no world-content obtained in such more or less unconscious ways could be made available for the building of a new scientific world-conception. Only as much as man experiences through the sight of a single, colour-blind eye, could be used.9 * If we would understand the role of science in the present phase of human development, we must be ready to apply two entirely different and seemingly contradictory judgments to one and the same historical phenomenon. The fact that something has occurred out of historical necessity - that is, a necessity springing from the very laws of cosmic evolution - does not save it from having a character which, in view of its consequences, must needs be called tragic. In this era of advanced intellectualism, little understanding of the existence of true tragedy in human existence has survived. As a result, the word 'tragedy' itself has deteriorated in its meaning and is nowadays used mostly as a synonym for 'sad event', 'calamity' 'serious event', even 'crime' (Oxford Diet.). In its original meaning, however, springing from the dramatic poetry of ancient Greece, the word combines the concept of calamity with that of inevitability; the author of the destructive action was not held to be personally responsible for it, since he was caught up in a nexus of circumstances which he could not change. This is not the place to discuss why tragedy in this sense forms part of man's existence. It suffices to acknowledge that it does and, where it occurs, to observe it with scientific objectivity.