In well-ordered legal traditions, disagreement about outcomes is expected. Disagreement about methods is tolerable. But the abandonment of method altogether marks a deeper rupture, one that transforms law from a system of constraint into an instrument of will.
Contemporary Brazilian jurisprudence increasingly reveals such a rupture. The problem is often framed as a conflict between legal theories, or as the natural evolution of constitutional interpretation. Yet this framing misidentifies the phenomenon. What is at stake is not the triumph of one doctrine over another, but the quiet dissolution of the very structures that once constrained judicial power.
Consider two influential concepts that migrated into Brazilian legal discourse from distinct traditions: proportionality and reasonableness.
In the German constitutional tradition, especially as articulated by Robert Alexy, proportionality is not a vague appeal to fairness. It is a structured method, composed of sequential steps, suitability, necessity, and proportionality in the strict sense, each requiring independent justification. The method is demanding by design. It disciplines judicial reasoning and imposes an argumentative burden that cannot be bypassed without exposing the decision to critique.
By contrast, reasonableness—rooted in Anglo-American jurisprudence—operates as a more diffuse standard. It does not impose a rigid sequence but evaluates whether a decision is acceptable within a given context. From the deferential posture of the Wednesbury case (1948) to the broader due process tradition, reasonableness functions less as a structured test and more as a boundary condition, excluding what is manifestly arbitrary rather than prescribing a strict path of justification.
These two concepts were not designed to be interchangeable. They emerged from different institutional histories, reflect distinct epistemological commitments, and perform different roles within their respective systems. Yet, in Brazil, they are frequently invoked side by side, or even as synonyms.
The consequences of this fusion are not merely semantic. When proportionality loses its structure and reasonableness loses its restraint, both cease to function as limits. What remains is a vocabulary of control that no longer controls. This development becomes more troubling when placed against the broader background of legal theory.
Even the most criticized framework of the twentieth century, the normativism of Hans Kelsen, sought to constrain judicial discretion through a hierarchical system of norms. Validity flowed from higher to lower levels, and the judge—though not mechanically bound—operated within a structured order.
Similarly, Ronald Dworkin—often read as a critic of positivism—did not advocate interpretive freedom without limits. His notion of law as integrity required coherence with principles and precedents, placing the judge within an ongoing narrative rather than outside it.
These theories differ profoundly in their assumptions. But they share a common feature: both resist the idea that judicial decision is an act of unconstrained creation.
The same is true, in a deeper sense, of the classical tradition. From Roman law’s distinctions to the synthesis achieved by Thomas Aquinas, there persisted an intuition that law does not originate in the will of the decision-maker. It reflects, however imperfectly, an order that precedes it.
Against this background, the contemporary situation reveals not a theoretical dispute, but a structural inversion.
Judicial decisions increasingly appear to precede their own justifications. Concepts such as proportionality and reasonableness are invoked not as methods to guide reasoning, but as post hoc validations of conclusions already reached. In such a context, the distinction between interpreting the law and producing it begins to blur.
This is not to suggest that any legal system can eliminate discretion, nor that judges should be reduced to automatons. But when discretion loses its internal constraints, when method is replaced by vocabulary, the risk is not flexibility, but arbitrariness.
Historical experience offers sobering reminders of what follows when adjudication becomes detached from structure. There have been moments in which legal proceedings seemed to invert their natural order, with conclusions preceding reasons and individuals fitted to judgments rather than judgments derived from law.
The warning, however, does not depend on direct comparison, it lies in the logic itself. If legal doctrines become interchangeable, if methodological steps can be skipped without consequence, and if justificatory language serves primarily to legitimize rather than to constrain, then the law ceases to function as a system of limits. It becomes, instead, a flexible medium through which power expresses itself.
The paradox is striking. Concepts originally developed to restrain authority can—once detached from their original frameworks—be repurposed to expand the very power they were meant to contain. In losing their structure, they lose their function. And what remains is not the triumph of one legal tradition over another, but the erosion of all of them.
