This book intends to help understand and apply principles and rules better. Its target is to keep the distinction between principles and rules whereas structuring it on different foundations than those jurisprudence ordinarily employs. The first object of investigation is the phenomenon of interpretation in Law in order to understand that the classification of certain normative species as either principles or rules depends in the first place on axiological connections that are not ready prior to the interpretation process that unveils them. Then, a definition of principles is proposed, aiming to understand what their unique characteristics are when compared to other norms of the legal order. Thirdly, the conditions for the application of principles and rules are examined, which are the normative applicative postulates...

Instead of the usual apologetic treatment found in legal doctrine, linked to the determinacy, immutability or predictability of norms, this book treats legal certainty innovatively, holistically and in depth. Using a method at once analytical and functional, Professor Avila examines the structural elements of legal certainty, from its definition and foundations to its various dimensions, normative forces and efficacies, citing a wealth of examples from case law to support each of the theses defended. No subject is more important and topical than legal certainty. Problems relating to lack of understanding, instability and unpredictability of law intensify day by day everywhere, in civil law and common law countries alike. Normative sources are increasingly diverse in origin (national, international, community) and multiple in nature (legal, contractual, jurisprudential). They change constantly, and present increasingly frequent problems of ambiguity and vagueness that significantly hinder their comprehension. This state of affairs, which to a greater or lesser extent is true of any legal order, justifies a return to the subject of legal certainty. In this book, essential questions are answered such as: Legal certainty in what sense? Certainty of what, for whom, in whose vision and by whom? When, to what extent, and to what end? "(...) it is probably the most comprehensive and systematic study ever produced on this subject using the analytical method." (Riccardo Guastini, Professor of Jurisprudence, University of Genoa, Italy)

Instead of the usual apologetic treatment found in legal doctrine, linked to the determinacy, immutability or predictability of norms, this book treats legal certainty innovatively, holistically and in depth. Using a method at once analytical and functional, Professor Avila examines the structural elements of legal certainty, from its definition and foundations to its various dimensions, normative forces and efficacies, citing a wealth of examples from case law to support each of the theses defended. No subject is more important and topical than legal certainty. Problems relating to lack of understanding, instability and unpredictability of law intensify day by day everywhere, in civil law and common law countries alike. Normative sources are increasingly diverse in origin (national, international, community) and multiple in nature (legal, contractual, jurisprudential). They change constantly, and present increasingly frequent problems of ambiguity and vagueness that significantly hinder their comprehension. This state of affairs, which to a greater or lesser extent is true of any legal order, justifies a return to the subject of legal certainty. In this book, essential questions are answered such as: Legal certainty in what sense? Certainty of what, for whom, in whose vision and by whom? When, to what extent, and to what end? "(...) it is probably the most comprehensive and systematic study ever produced on this subject using the analytical method." (Riccardo Guastini, Professor of Jurisprudence, University of Genoa, Italy)

This book examines the distinction between principles and rules so that they can be better understood and applied. It structures the distinction between principles and rules on different foundations than those jurisprudence ordinarily employs. It also proposes a new model to explain the normative species, which includes structured weighing on the application process while encompassing substantive criteria of justice in its argument.