Similarity and Dissimilarity

In the chapter basic principles of color theory we have learned that we can only visually perceive our environment because there are optical contrasts which are produced by the reflection of light: light-dark contrasts and color contrasts. Only these contrasts make a three-dimensional orientation in our world possible. We would not be able to identify anything without these contrasts - as if the environment was covered with fog, a monotonous mass without contrasts and patterns. Our brain has to go through a decision-making process between perceiving and classifying a sensory impression: It assesses all sensory impressions by the contrast of similarity and dissimilarity.
 
Our brain thus tries to detect an additional contrast in order to find a further distinguishing feature. This additional contrast allows to make subtler and more accurate differentiations. In this way it is easier for the brain to get a better overall view of the environment. Light-dark contrasts and color contrasts are complemented by the additional contrast of sameness and variety, i.e. of similarity and dissimilarity. The shapes that have been identified by our brain are classified according to the attributes of similarity and dissimilarity.
 
This search for similarity and dissimilarity is equal to the search for order. If our brain finds similarity or dissimilarity, it can establish order between all the objects. By establishing order, our brain faster gets "a good grip" on the situation. Our brain likes to have an overall view of the surroundings; it wants to see and know everything. On which chair would a person sit down if there were many to choose from? Experiments in behavioral sciences have shown that we always choose those chairs from which we can overlook the whole room, i.e. we always choose those chairs standing at the wall and not in the middle of the room. Just think of a waiting room. This picture speaks for itself: All chairs are placed at the wall, no matter if the room is used efficiently or not.
 
If the task of classifying the environment is difficult and cannot be solved promptly, our brain gets exhausted and we find this task unpleasant. This task gets especially difficult, if our brain detects both features of similarity and dissimilarity. Consequently, our brain cannot get an overall view of the environment because it finds contradictions everywhere; the brain cannot sort out whether it sees similarity or dissimilarity. And this unpleasant feeling is the sensation of disharmony.
 
If this task can be solved quickly, it is easier for our brain to cope with the established order; it has a better overall view of the surroundings and therefore feels very comfortable. And this feeling is the sensation of harmony. The task of classifying the objects can be solved quickly, if the brain makes out right off either similarity or dissimilarity.
 
I have to remark that science has not yet identified all processes which occur in the eye and brain while classifying the environment, and therefore cannot give a final explanation of the physiological processes. Hence, we depend on philosophical speculation and have to content ourselves with the most probable explanation.
 
On the following page these theoretical considerations will be illustrated with examples.