3 -Ideology

Finally, formation of social units was based on belief, mentality, and ideology in the more perfect societies. Man understood soon that the issue of race and tribe could not separate the individuals. It is true that consanguine individuals have more common features in the physical and spiritual aspects, but this is never so critical to avoid their coexistence.

And it is easily perceived that difference of geographical areas, either natural or arbitrary, can not cause separation, especially when the issue of geographical distance was totally solved through the facility of communication and transportation means, and all parts became close to each other.

So, little by little the social units changed into belief andideological units, and mental borders replaced previous ones.

Division of world's countries into two communist andcapitalist blocks is one of the manifest samples of this sort ofclassi fication.

Although, at the beginning it was supposed this classif icationis an eternal and everlasting one, and the non- possibility ofrecon ciliation between these two doctrines was introducedde finite and inevitable, but it was gradually found that thearti ficial aspect of this division and separation is much morethan its real aspect, because there are thousands of commonaspects among different classes as compared with aspects ofmental and belief disagreement, the source of which is man'sunity and unity of structure of his spirit and body resulting insharing of different objectives.

So, different regimes and ideologies supported the murmurof coexistence among social units, and step by step, it waschanged from speech to action.