Ibn Khaldun's term for the bloodbound solidarity that makes a people warlike and communitarian. Civilizations rise and fall with it.
If particularism defines the horizon of care, Ibn Khaldun's concept of asabiya (group feeling, solidarity, clannishness) names the cohesive force within that horizon that both enables and motivates the folk to compete with other groups. Asabiya is both social glue and source of vitality.
According to Khaldun, asabiya results only from blood or a proxy for blood. Creed can sometimes serve as a proxy for blood when it roughly maps onto blood. But once religion or ideology becomes too universal, it dissolves rather than reinforces asabiya.
Asabiya is what makes a people warlike and communitarian. Some people have died for ideas, but far more often they have died for their kin. Every great civilization stands atop the foundation laid by tribal barbarism, drawing from a deeper reservoir of bloodbound solidarity. If that reservoir is not replenished, civilization eventually dies.
Asabiya tends to be strongest among rural populations whose conditions demand cooperation, sacrifice, and toughness. As societies expand, urbanize, and soften, the original group feeling attenuates. Something more abstract, usually religion or ideology, is brought in to hold things together, but this surrogate identity is weaker than the organic one it replaced. Over time, vitality ebbs away, and the civilization becomes ripe for conquest by another folk with more asabiya.