Modernism was named retroactively while postmodernism preceded its practices

Evidence

Historically modernism was essentially a post facto category, unifying after the event a wide variety of experimental forms and movements, whose own names for themselves knew nothing of it. By contrast, postmodernism was much closer to an ex ante notion, a conception germinated in advance of the artistic practices it came to depict. — Perry Anderson, The Origins of Postmodernity, 238

Categorization

• XREF: The post facto versus ex ante distinction reshapes how one reads any ‘ism’ — connects to classicism, Romanticism, and other retrospective labels in art history. — connects to: Jameson’s postmodern problematic predates his adoption of the term by a decade — Perry Anderson, The Origins of Postmodernity, 172; Postmodernism precedes and enables modernism rather than following it. — Jean-François Lyotard, The Postmodern Condition: A Report on…, 502; Canonization of modernism retroactively defined all later art as its post. — Aijaz Ahmad, In Theory: Classes, Nations, Literatures, 484 (+1 more)
• DEFINE: A precise conceptual distinction clarifying the two movements’ different epistemic status.

Broader Connections

• Postmodernism precedes and enables modernism rather than following it. #corroborates (0.85) — Jean-François Lyotard, The Postmodern Condition, 502