Inter-group aggression: the multi-individual organism and the survival instinct.
Inter-group aggression, carried out at the level of the in-groups and out-groups of ethnocentric theory, continued unabated throughout the twentieth century. Its frequency, together with its ferocity, indicates a potent biological cause. We have evolved as social animals, and it is postulated that evolution has proceeded to such an extent that 'multi-individual social organisms', that is, 'social groups that fight each other are self-sustaining, self-replicating whole containing interdependent parts'. This results from the total integration of individuals into the social structure and culture of the in-group; individuals are inseparable from their society and evidence for this proposal is given. Cohesion is given through the collective consciousness and collective memory. The analogy is to multicellular organisms that evolved from the association of single cell organisms. All biological organisms are subject to the survival instinct, which is thus the potent biological cause of inter-group aggression. Groups compete for territory and see other groups as a threat. Prevention of inter-group aggression should come from the insight that threatening behaviour endangers the integrity of the society of out-groups, initiating conflict.