The Serpent's Egg

The Brazilian magazine Piauí published an article called “Excelentíssima Fux” — “His Excellency Fux,” with a feminine twist. The title is not gratuitous irony. The daughter of Supreme Court Justice Luiz Fux became an appellate judge — not through the silent osmosis of someone carrying a complicated surname in a courthouse hallway, but because her father called. He called whoever needed to be called, used the weight of his office, and made the mechanism work — the one that in Brazil never needed a name because it never needed shame. Faoro called it patrimonialism. Sérgio Buarque called it cordiality. Piauí called it His Excellency. None of the three was wrong.

Fux is not the exception that proves the rule. He is the rule that found quality journalistic documentation. What makes the case singular is not the phone call — it is that Fux chaired the commission that drafted the Civil Procedure Code of 2015. And inside that code, in the hands of this man, something was incubated with which patrimonialism is radically incompatible.

Patrimonialism and its serpent#

Judicial patrimonialism has a natural enemy: the duty of rationality.

Not the duty to provide formal reasoning — the system already had that, in the form of Article 131 of the 1973 Code of Civil Procedure, which required the judge to “indicate the reasons that formed his conviction.” Decades of legal practice reduced this requirement to a surface formality: anything written served as a reason. The decision was reasoned as long as there were words in the space for reasoning. Livre convencimento motivado — motivated free conviction — became the principle that protected judicial discretion not from external arbitrariness, but from having to justify itself. It was the tamed serpent — the animal transformed into a living room ornament.

The substantive duty of rationality is different. It is the requirement that the reasoning identify the determining grounds of the precedent invoked, confront arguments capable of undermining the conclusion, demonstrate why the case fits the ratio — and not merely declare that the judge so understood. This duty is incompatible with patrimonialism because patrimonialism lives on opacity: personal prerogative only functions as long as it does not need to justify itself. The demand for substantive rationality is light on the egg.

Lenio Streck named this. Coming from philosophical hermeneutics, he arrived at the same diagnosis by another path: the judge who “decides according to his conscience” is not exercising rational freedom — he is exercising personal power disguised as legal principle. He spent years doing what he himself called “epistemic lobbying” within the commission drafting the new code. The serpent of the duty of rationality — Streck wanted it to be born.

The egg#

The egg is Article 489, §1, of the Civil Procedure Code of 2015.

A decision is not considered reasoned if it merely invokes a precedent without identifying its determining grounds. A decision is not considered reasoned if it fails to confront arguments capable of undermining the conclusion. A decision is not considered reasoned if it employs indeterminate legal concepts without explaining their concrete application. A decision is not considered reasoned if it invokes reasons that would serve to justify any other decision.

Alongside this, Article 371 eliminated the word “freely” from the evaluation of evidence. Livre convencimento motivado — the living room ornament, the tamed serpent, the principle that protected opacity — lost its name in the legal text.

graph LR
    A["Judicial patrimonialism<br/><em>personal power without accountability</em>"] -->|"natural enemy"| B
    B["Duty of rationality<br/><em>the serpent</em>"]
    C["Streck + CPC 2015 commission"] -->|"incubated"| D
    D["Art. 489 §1<br/><em>the egg</em>"]
    D -->|"hatches into"| B
    B -->|"existential threat to"| A

The egg was laid inside the patrimonial system by the hands of its most eloquent representative. Fux chaired the commission. Fux signed the draft. Fux did not realize — or did not want to realize, which amounts to the same thing — that Article 489, §1, was the egg of a serpent that would attack exactly the kind of power he exercised outside the code and inside his office.

It is Bolsonaro signing the criminal law that would one day come back to judge him.

What happens when the egg hatches#

The serpent of the duty of rationality, when applied consistently, does not respect hierarchy. Article 489, §1, of the Civil Procedure Code contains no exception for the Supreme Court. Article 93, IX of the Constitution requires that all decisions of the Judiciary be reasoned — all of them, without distinction by level.

The argument without footnotes is this: a Supreme Court that responds to a complaint against a decision that deviated from a binding precedent using solid arguments, and responds only with “the binding precedent so determines,” is violating the same Article 489, §1, that the code installed. The serpent born from the egg attacks upward too.

This is what makes the cycle uncomfortable for those who built it. The duty of rationality that the CPC 2015 installed — and that Fux helped install without perceiving its full extension — is the instrument that makes visible the absence of substantive reasoning in the Supreme Court’s own decisions. Including Fux’s. The egg hatches its architect.

The habitus and the serpent’s body#

The egg has hatched. The serpent is still growing.

It is a notorious fact that the phrase livre convencimento motivado — “motivated free conviction” — continues to be used by Brazilian courts as if the CPC 2015 did not exist: in trial courts of first instance, in appellate chambers, in monocratic decisions by justices who should know better. The expression was eliminated from the legal text in March 2016 and immediately resurrected in legal practice, as if the head had been cut off and the body had decided to keep crawling on its own.

DiMaggio and Powell called this mechanism superficial coercive isomorphism: the norm changes, the language adapts at the surface, and the underlying behavior remains. The problem is not lack of law — the CPC 2015 is a good law. The problem is that the patrimonial habitus, formed over decades in which anything written served as motivation, is not deconstructed by decree. Bourdieu called it history turned into nature: incorporated history that operates as second nature, making certain practices spontaneous and others unthinkable. Planck said of science that it advances funeral by funeral — opponents of a new truth are not convinced, they die, and the next generation grows up knowing nothing else. Law is no different. The serpent of the duty of rationality will not convince those who internalized free conviction as reflex. It will be natural for those who entered law school when the code already existed — if the habitus does not prevail first, transmitting itself to new generations through the same institutions that produced it.

What makes the current situation different from all previous ones is that the costs of producing quality argumentation are falling. Not dramatically yet, but systematically. Every time a state attorney or public defender manages to produce, in reasonable time, a brief with structured reasoning that identifies the determining grounds of the precedent invoked and demonstrates the case’s fit, the serpent of the duty of rationality grows a little. Every such brief that reaches the Supreme Court — and that the Court must decide whether to confront or ignore — is a moment in which the egg is opening.

Bolsonaro once said, with the involuntary candor that sometimes characterized him, that he would indeed favor his son. That is patrimonialism that knows itself as patrimonialism and sees no problem with it. Fux is different — he has scruples, believes in the system, helped build a code that is genuinely good. And yet he defended his daughter for the appellate judgeship, called whoever needed to be called, used the weight of his office. Not because he calculated coldly and concluded that personal prerogative is worth more than principle. But because the patrimonial habitus operates below the level of conscious deliberation — it is incorporated disposition, not choice. The man who wrote Article 489, §1, did not notice the contradiction between what he wrote and what he did.

Do not be misled by sophistication. The proof is in the judgment.

Streck knew what he was doing when he pressed for the elimination of free conviction. Fux signed the code. The egg was in both of them — but with very different awareness of what they were hatching.

In 2025, when Bolsonaro was tried at the Supreme Court for involvement in the attempted coup, Fux delivered approximately eleven hours of opinion in favor of acquittal — more vehement in defense than the lawyers hired for that purpose. Fux took it personally. The argument was procedural: jurisdiction, privilege of forum, formal questions. The habitus does not need substantive argument to function. It recognizes its own and moves.

The serpent is being born. Slowly, with resistance from all parties that have an interest in it not being born. But it is being born.

A credit note: I am a disciple of Streck’s hermeneutic tradition, albeit with disagreements that deserve their own post — including about what AI represents for law, where we have reached opposite conclusions.

And Yudkowsky stays here at the end, because intellectual honesty is what one attempts: this essay presupposes that AI is a tool for rationalizing the legal system. That may be true for the legal system and still be only one of the possible stories about what comes next. What comes after the serpent — when AI is no longer an audit tool but a decision agent — is where Yudkowsky begins and this essay stops.

Further reading#

• Lenio Streck, O que é isto — decido conforme minha consciência? (What is this — I decide according to my conscience?) — the most direct diagnosis of Brazilian judicial solipsism; Streck named the problem when naming was inconvenient and kept naming it afterward.
• Raymundo Faoro, Os Donos do Poder (The Owners of Power) — the genealogy of Iberian patrimonialism in the Brazilian state; the minister’s phone call is not an anomaly — it is a consequence of a structure that Faoro described with precision in the 1950s.
• Sérgio Buarque de Holanda, Raízes do Brasil (Roots of Brazil) — the “cordial man” and the Brazilian difficulty in separating person from function; more current than it should be, ninety years later.
• Paul DiMaggio and Walter Powell, “The Iron Cage Revisited” (American Sociological Review, 1983) — the three mechanisms of institutional isomorphism; explains why the CPC 2015 produced linguistic conformity without behavioral change in much of the Judiciary.
• Douglass North, Institutions, Institutional Change and Economic Performance — why weak enforcement transforms good norms into decoration; the serpent of the duty of rationality needs an enforcement mechanism to grow.
• Daniel Mitidiero, Precedentes: da persuasão à vinculação (Precedents: from persuasion to binding force) — the procedural argument about rational versus hierarchical binding; the duty of reasoning is symmetric and applies to the Supreme Court when judging complaints.
• Marc Galanter, “Why the ‘Haves’ Come Out Ahead” (Law & Society Review, 1974) — on how repeat players structure the legal system to their advantage; the minister’s phone call is the repeat player in its most concentrated form.