Decisions are made. Reasons are added afterwards. This book examines a profound structural shift: justification has ceased to steer decisions and survives only as retrospective legitimation. In systemic environments, automated processes, and stabilised decision architectures, decisions emerge without deliberation, without judgement, without rational justification. Systems do not choose because reasons persuade, but because conditions take effect. Discussions no longer change anything. Transparency explains – it does not steer. "Decision Without Justification" is neither an attack on reason nor a plea for arbitrariness. It is a reconstruction: how justification moved from the origin of decision to its communicative aftercare. Why rationality lost its steering function and legitimation mutated into a social mechanism of connectivity. Rethinka writes from the perspective after the fact. Not to evaluate decisions, but to make visible what happens when reasons no longer decide – but merely explain. This book does not ask why a decision was made. It shows why that question has lost its effectiveness.