A social formation is a structured complex where no single practice reduces to another.

Evidence

As against this, Althusser proposes that we must understand a social formation as “an ever pre-given structured complex whole.” There is no simple essence, underlying or predating this structured complexity, to which any single practice—e.g., the production of ideology—can be effectively reduced. … Any relation within this structured complexity will have its registration, its “effects,” at all the other levels of the totality—economic, social, political, ideological; none can be reduced to or collapsed into the other. If, nevertheless, this social formation—now conceptualized not as an “economic basis” and its “reflexive superstructures” but rather as a structure-superstructure complex—is not to be conceptualized as a series of totally independent, autonomous, and unrelated practices, then this relatedness must be “thought” through the different mechanisms and articulations which connect one with another within the “whole”—articulations which do not proceed in an inevitable tandem, but which are linked through their differences , through the dislocations between them, rather than through their similarity, correspondence, or identity. (See Hall, “A ‘Reading’ of the ‘1857 Introduction.’ ”) The principle of determinacy—which, as we saw, is fundamental to any materialist theory—must therefore be thought, not as the simple determination of one level (e.g., the economic) over all the others, but as the structured sum of the different determinations, the structure of their overall effects. — Hall, Stuart, Essential Essays, Volume 1, 895

Categorization

• DEFINE: Defines the Althusserian ‘structured complex whole’ and overdetermination in crisp terms — social levels linked ‘through their differences,’ determinacy as the structured sum of determinations.
• XREF: Connects to broader reading of Marxism and Form and the Frankfurt School debates over base-superstructure reductionism, plus Hall’s own work on articulation.
• ADDENDUM: The rejection of ‘His Majesty, The Economy’ as a naked principle of determination parallels how each of the three published essays treats economic determinism — here it is a structural-level theory about ideology, not dress, trees, or sacrifice.