In this work, Paul M. Postal supports the universalist theory of language by examining passive clauses. Contrary to a skeptical tradition, Postal argues that passive clauses are cross-linguistically identifiable and characterizable. This study proposes refinements of the analysis of the natural language grammatical category Passive Clause. These refinements include an account of the notion 'dummy nominal, ' central to the analysis of impersonal passive clauses; additions permitting a proper typology of the major known subtypes of Passive Clause; a generalization permitting application to clauses whose subjects are not earlier level direct objects; and, construction of precise rule concepts to represent restrictions on passive clauses. The passive domain supports the universalist approach in three distinguishable ways: (1) by permitting formulation of otherwise apparently unstatable lawful characteristics of all passive structures; (2) by facilitating statement of language-specific passive constraints holding in diverse languages; and, (3) by allowing uniform statement in grammars of recurrent constraints on passives. Each mode of support is applied to actual cases based on material from more than a dozen languages from English and French to Quiche (Mayan) and Chi-Mwi: ni (Bantu).