UNDERSTANDING, STABILITY AND PREDICTABILITY: THE THEORY OF LEGAL CERTAINTY IN BRAZILIAN CONSTITUTIONAL JURISDICTION

Abstract

This article examines legal certainty as a structuring principle of the Democratic Rule of Law, adopting Humberto Ávila’s theoretical framework, particularly his three fundamental pillars: comprehensibility, stability, and predictability. The study is based on the premise that legal certainty cannot be reduced to the mere formal protection of enacted norms, but also encompasses the intelligibility of the law, the stability of legal relationships, and the rational anticipation of the legal consequences arising from state action. The article analyzes the constitutionalization of legal certainty within the 1988 Brazilian Federal Constitution, its relationship with legal institutions such as vested rights, res judicata, due process of law, and the protection of legitimate expectations, as well as its influence on judicial and administrative activities. Furthermore, it examines the role played by Brazilian constitutional jurisdiction — especially the Federal Supreme Court — in preserving or undermining the stability and predictability of the legal system, considering topics such as precedents, general repercussion, binding precedents, and the modulation of effects in abstract judicial review. The research adopts a deductive methodology grounded in bibliographical review and doctrinal analysis, aiming to investigate the contemporary challenges of legal certainty within Brazilian constitutionalism and the growing centrality of constitutional adjudication.