Anti-capitalist thinkers in the West have long argued that the expansion of markets creates new wants faster than it can satisfy them, and that consumption under capitalism is a form of addictive behavior. Recently, however, the relentless expansion of desire has come to be seen as a strength rather than a weakness of capitalist regimes. To understand this change socialists must consider whether there is a point to consumer spending that goes beyond satisfaction with what one gets. Freud's notion of (...) instinctual ambivalence illuminates the ways in which spending itself is a fusion of the desires to lose and to gain. This helps to explain how the socialist distinction between satisfying and addictive consumption misses the mark. Broadening this insight, we can see that Western thought about justice, originating in Judeo-Christian theology, conceals a fundamental ambivalence about both domination and gain by suggesting that inequality (beginning with that between God and man) is justified when the dominating party loses and the gainer submits. Ironically, however, the new post-utilitarian rationale for capitalism undermines this putative justification of social inequality in consumer-oriented capitalist societies by bringing our internal ambivalence about gain and dominance to the surface. This development creates an opportunity for a new beginning in Marxian social theory. The final sections of the essay suggest that social theory has been trapped in a debate over whether predators (and their human counterparts) kill in order to eat or eat in order to kill (Marx vs. Nietzsche). To break this trap we must shift the basis of social criticism from the metaphor of predation to the metaphor of parasitism. This changes the focus of critical analysis from unmasking the predator in every situation to identifying in every social structure the mechanisms of incorporation, mutual subversion, asymmetrical exchange, and surplus-creation (as distinct from equilibrium). If neither the desire for gain nor the desire for dominance are self-explanatory, then the Marxian critique of Nietzsche and the Nietzschean critique of Marxism both have valid points. The essay concludes with reflections about the importance of addressing the post-utilitarian rationale of capitalism with the same depth and comprehensiveness that we find in Marx's critique of its utilitarian rationale. (shrink)