Ordering the Fragments International Law under the Planetary Crisis

International law operates under persistent normative fragmentation: specialised regimes have produced a decentralised body of norms prone to conflict. For many international lawyers, however, the debate now appears settled, buried by the International Law Commission’s work on systemic integration and the turn to regime interaction and normative pluralism. But the ghosts of fragmentation are revenants: they return precisely when the matter is believed to be settled. The triple planetary crisis of climate change, biodiversity loss, and pollution has made the haunting plain, revealing that the fractures once discussed as technical problems of consistency are symptoms of a deeper condition: a world whose ecological, legal, and political orders do not align. This book investigates how consistency is possible within a fragmented order. Rather than surveying the responses of international legal scholarship, the book offers a rational reconstruction of the concept of consistency in international law, making explicit the implicit logical structures through which legal actors reason. The book distinguishes facts, norms, and reasons as the building blocks of legal argumentation and shows how legal actors can derive statement-consistent conclusions even where the underlying norm-set is itself norm-inconsistent. International law, on this account, sustains itself not by eliminating inconsistency but by reasoning through it. Conflict avoidance operates upstream through meta-norms that affect validity and the conditions of applicability; where it fails, priority reasoning and reason-based argumentation determine which norm applies. The consistency achieved is local, provisional, and plural, but it is genuine, disciplined by constraints and accountable to the requirement of justification. The framework does not prescribe which priorities legal actors should adopt but it clarifies the grammar of the practice that instead makes these determinations. The book argues, however, that incorporating planetary boundaries as legal constraints would narrow the space of admissible outcomes in ways decisive for the planetary crisis.