7.7 Interactive properties are a criterium for selection
Development, whether it occurs in cells, systems, children or cultures, is never linear, but always interactive. The diversity of temperaments displays its full advantage when different human varieties interact and cooperate for a common purpose. Man is a gregarious animal. This enables individuals to follow their genetic endowment and add to their special skills and inclinations. Tasks can be distributed among specialised individuals within a social group. The group thus increases its fitness and this has led to evolutionary enhancement of diversity in the human species. The evolution of diverse genotypes is controlled by gene-selection. Those genes are selectively reproduced over the generations that have given the carriers (phenotypes) an advantage regarding survival and reproduction. This goes for individuals as well as for groups.
In a social structure such as any human society there is an advantage when individuals of different constitutional cooperate. Mutual reinforcement of idiotypes that fit in well with the aims of the group, establish a dynamic network of human cooperation. In the fourth century BC the Greek author Plato had already ventured an opinion on the subject. He observed three classes or types of people functioning in a nation:
the peasants and merchants who produce and distribute goods. Their primary drive is the desire of property; their main virtue is moderation.
the soldiers who maintain the laws, do this inspired by willpower; their main virtue is courage.
the administrators who are also philosophers. Their strength is rational thought, their main virtue is wisdom.
Consideration and justice are virtues that can be exerted by all three classes. The similarity with the three dominant temperaments: viscerotonia, somatotonia and cerebrotonia is obvious. It confirms the idea of a three-partitioned social orientation which is deeply rooted in human consciousness. Plato referred to classes of people manifesting different attitudes toward life, as well as having different values and morals. Others have carried these ideas further (7.8). Plato also compared the organisation of a nation with the cooperating parts of a living organism. The Systemics approach in the natural and social sciences (J.G.Miller, 1965) has given a new impulse to these analogies.