Lyotard defines the modern by its appeal to grand legitimating narratives

Evidence

I will use the term modern to designate any science that legitimates itself with reference to a metadiscourse … making an explicit appeal to some grand narrative, such as the dialectics of Spirit, the hermeneutics of meaning, the emancipation of the rational or working subject, or the creation of wealth. — Alex Callinicos, Against Postmodernism, 30

Categorization

• DEFINE: Captures Lyotard’s canonical definition linking ‘modern’ to metanarrative legitimation — the pivot for the whole postmodernism debate.