The introduction of Part II of this book highlights that the polluter-pays, preventive, and precautionary principles described in Part I mark an epistemological shift between modern law, which rests on the fixed standards of traditional legal rule-making, and post-modern law, which emphasizes the pragmatic, gradual, unstable, and reversible nature of rules. Chapter 4 describes the paradigm shift from modern to post-modern law. Chapter 5 considers the various functions that the polluter-pays, preventive and precautionary principles may fulfil within a post-modern legal prospect, seeking to strike a balance among multiple and conflicting interests. Chapter 6 explains that the varying status of these principles does not deprive them of normative effect. Chapter 7 focuses on the conflict between environmental principles and free trade within the World Trade Organization (WTO). This four-stage approach enables us to demonstrate how the polluter-pays, preventive, and precautionary principles shape an ideal of rationality in a chaotic legal universe.