Over the past three decades, the German welfare state has undergone more reforms than in the five decades before — and in the process has not stabilised but destabilised. This paper advances the thesis that the structural cause of recurrent reform crises lies not primarily in demography, scarcity of funding or a shortage of skilled personnel, but in the systematic conflation of four welfare-state logics: Insurance (collective, contribution-based), Social Assistance (individual, tax-based), Public Provision (collective, tax-based, territorially anchored) and Market (individual, premium-based). The Welfare State Matrix develops an analytical diagnostic model — not an empirical causal model. Methodologically it follows the construction of ideal types in the Weberian sense (Weber, 1922) and makes visible where the effect of welfare-state reform is systematically absorbed by structural logic breaks. The analysis shows that exemplary fields of reform — the contribution-based health-insurance cover of recipients of Germany’s means-tested minimum income support system (Bürgergeld), the capacity funding of hospitals, the interface between statutory and private health insurance, and the structures of primary care — display a consistent pathology: at each of these points incompatible logics meet without the conflation having been resolved in architectural terms. In the case of the primary-care centre this pathology appears in especially concentrated form — here all four logics converge at the level of a single care institution. Reform efforts fail less because of an absence of political will than because of this unresolved structural conflation. International reference systems show that architectural clarification is not only practically feasible but leads to structurally more stable and demonstrably more capable care systems: the Netherlands, with the separation — established since 2006 — of the Zorgverzekeringswet, the Wet langdurige zorg and the Wet maatschappelijke ondersteuning, whose reformed system held leading positions in international performance comparisons for years; and the Swedish system, with its regional tax funding. The paper proposes a Welfare State Architecture Act on the model of regulatory framework legislation, a parallel restructuring of the Social Code (Sozialgesetzbuch) along the four logics, and a step-by-step clarification strategy directed at the most costly logic breaks. The Welfare State Matrix makes this architectural clarification possible; it is not itself a reform programme but supplies the hitherto unstated precondition for the success of any such programme.