This chapter explains the final aspect of Marx's philosophy in accordance with the tripartite division of methodology, description, and norm. The most salient paradox is to be found in the juxtaposition of two facts: first, that Marxism is clearly more heavily oriented towards a social ideal than almost any other important system of philosophical thought in the past century and a half, and second, that Marx disdained ideal-mongering and wrote relatively little about the features that he would expect to characterize future society. Engels, in an essay that has become justly acclaimed as a succinct though often dubious introduction to Marx's thought, lays down the gauntlet to those who claim to discern a host of social 'oughts' in Marxism. Marx's radical, open-ended vision of a realm of freedom serves to orient his entire thought, but it does not distract him from engaging in the often excruciatingly detailed critical analysis of existing social structures that he regarded as his theoretical task.