"What if loneliness is like hunger, an evolved trait that provides a clear evolutionary advantage for those who experience it. Without the capacity for painful loneliness many would simply flee from the difficulties of civil society. Yet I would bet that many varieties of sociopaths and psychopaths have no capacity for real loneliness, just as they have not real capacity for empathy. Hume seems very informative here. There is no experience of a "self." Kant attempts resolve this with his "transcendental unity of apperception." Self is not an independent entity; so when human relationships falter and loneliness sets in so to does an erosion of self begin."