Lyotard and Habermas gave postmodernism no historical periodization

Evidence

The coincident interventions of Lyotard and Habermas for the first time sealed the field with the stamp of philosophical authority. But their own contributions were each strangely indecisive. The original background of both thinkers was Marxist, but it is striking how little of it they brought to their accounts of postmodernity. Neither attempted any real historical interpretation of the postmodern, capable of determining it in time or space. Instead, they offered more or less floating or vacant signifiers as the mark of its appearance: the delegitimation of grand narratives (dateless) for Lyotard, the colonization of the life-world (when was it not colonized?) for Habermas. Paradoxically, a concept by definition temporal lacks periodic weight in either. — Perry Anderson, The Origins of Postmodernity, 98

Categorization

• XREF: This lack of periodic weight is exactly the gap Anderson will show Jameson filling later — a key connective thread for an entry-point reader.