"Still, the frequent absence of happiness is what keeps us pursuing it, and thus makes us productive."10 This is a curious notion of productivity--at once overtly political and yet presented innocently enough, as if there were only one possible meaning of "productivity." This perspective on life incorporates the Protestant work ethic (that "productivity" is what makes an animal "effective") and echoes the Old Testament notion that life must be endured, not enjoyed. These assumptions are embedded throughout the literature of evolutionary psychology. Ethologist/primatologist Frans de Waal, one of the more open-minded philosophers of human nature, calls this Calvinist sociobiology."