**2. A centuries-old strife**

In order to illustrate our point of view, we will rely on a metaphor from the realm of physics. When water gets in touch with a different medium (maybe air or oil) through a definite surface, the two fluids do not merge. Rather, tension appears on the contact surface. Such tension is commonly explained in terms of an attraction among the molecules making up each fluid. In surface phenomena, we behold an attraction among equals and repulsion towards outsiders.

The parallel with human organizations is straightforward. A political border implies an inner alignment, and a reciprocally hostile attitude. The survival of larger or more restricted interpersonal systems requires intense cohesive forces. It requires the splitting and projection of interpersonal aggression towards an avatar located outside the group. Social elites have consistently exploited social aggression and intolerance towards foreigners and minority groups in order to foster the most lethal and dramatic of social phenomena: the war [5].

Over the last century, western society has gone through a piecemeal but apparently irreversible process: cohesive forces in groups have been weakening and then rapidly collapsing. The Communist Party, the trade unions, and the Catholic parishes have nearly disappeared and are now but shadows of what they were only forty years ago [6].

A parallel fragmentation process can be observed in family-ties-based groups. Intergenerational family is a memory, but nuclear family is getting slimmer by the day, due to dropping fertility rates, and even the sexual couple is slowly giving way to celibacy-oriented residential models.

As interpersonal ties seem to be colliquating by the day, aggression faces a unique fate: it is redirected from outside the social environment into the community itself. The immaterial chasm, which used to mark the border of the family, the village, and then the social classes, seems to be relocating inside the groups themselves and to split citizens according to preference in terms of ethical options and self-representations.
