The Latin expression ad probationem (for evidentiary purposes) designates a formality required by the legal system not as a prerequisite for the validity or existence of a legal act, but as a necessary means for its demonstration in court or before third parties. Integrated into Civil Law and Civil Procedural Law, this institute contrasts with the ad substantiam form, operating as a legal security mechanism that conditions the evidentiary efficacy of certain legal transactions upon the observance of specific documentary or instrumental support, without, however, nullifying the agreement in case of formal non-compliance.
1. Concept, Legal Nature, and Fundamental Distinctions
Within the scope of the General Theory of Civil Law and Evidence Law, the ad probationem tantum form is qualified as a legal requirement for the externalization of intent that aims, primarily, to facilitate the proof of the act and provide security to legal relations. Its legal nature is that of an accessory or complementary formality.
It differs substantially from the ad solemnitatem (or ad substantiam) form. While the latter is of the essence of the act—such that its absence entails nullity pleno jure (Art. 166, IV, of the Civil Code)—the ad probationem form does not affect the validity of the legal transaction. The act exists and is valid between the parties, but its judicial proof is restricted or hindered if the required instrument is absent. In short, in the ad substantiam form, the form is the very being of the act; in ad probationem, the form is the vehicle for its demonstration.
2. Historical and Doctrinal Evolution
Historically, Roman Law evolved from a rigid and ritualistic formalism (legis actiones) to a system of greater consensualism. In the classical period, the stipulatio required solemn oral forms. With the reception of Roman Law by modern codes, especially the Napoleonic Code of 1804, the principle of consensualism gained primacy, establishing that the meeting of minds, by itself, is capable of generating obligations.
In Brazilian Law, the 1916 Civil Code maintained greater rigor regarding the value of testimonial evidence for high-value contracts. The 2002 Civil Code (CC/02), in harmony with the 2015 Code of Civil Procedure (CPC/15), consolidated the freedom of forms as a general rule, reserving the ad probationem requirement for specific situations where human memory is considered insufficient or risky to support judicial conviction in isolation.
3. Legal Provision and Normative Framework
The pillar of the system of forms in the Brazilian legal order resides in Article 107 of the Civil Code, which states: "The validity of the declaration of intent shall not depend on a special form, unless the law expressly requires it." This provision enshrines the principle of freedom of forms (consensualism).
The ad probationem configuration manifests itself in the following fundamental provisions:
- Art. 227 of the Civil Code: Establishes that, except in express cases, exclusively testimonial evidence is only admitted in legal transactions whose value does not exceed ten times the highest minimum wage in force in the country at the time they were concluded. (Note: This article must be read in conjunction with the CPC).
- Art. 442 to 446 of the Code of Civil Procedure (CPC/2015): Regulate testimonial evidence. Art. 444 allows testimonial evidence as subsidiary or complementary when there is a commencement of written proof, emanating from the party against whom the proof is intended to be produced.
- Art. 212 of the Civil Code: Enumerates the means of proof (confession, document, witness, presumption, and expert testimony), serving as a basis for the admissibility of ad probationem acts.
4. Practical Application and Jurisprudential Understanding
The jurisprudence of the Superior Courts (STJ and TST) has applied the concept of ad probationem form in a way that upholds objective good faith and prevents unjust enrichment. The prevailing interpretation is that the absence of a written document in contracts that require it only ad probationem does not prevent the recognition of the existence of the legal relationship, provided it is corroborated by other elements of proof.
In the Superior Court of Justice (STJ): The consolidated understanding is that the limitation of value for exclusively testimonial evidence (Art. 227 of the CC and Art. 442 of the CPC) does not prevent the magistrate, based on the principle of free motivated conviction, from accepting testimonial evidence to prove defects of consent or when there is a moral or physical impossibility of obtaining written proof. (Ref: AgInt no AREsp 1.729.446/SP).
In the Superior Labor Court (TST): The ad probationem form is common in exclusivity clauses or apprenticeship contracts. Although the law requires written form for certain contractual modalities, Labor Justice, guided by the Principle of the Primacy of Reality, admits proof of service provision even without the formal instrument, the latter being required only for the purpose of proving specific conditions (ad probationem).
5. Correlated Principles and Doctrinal Divergences
The institute dialogues directly with the following principles:
- Principle of Freedom of Forms: The rule is consensualism; the requirement of form is an exception interpreted restrictively.
- Principle of Instrumentality of Forms: The act should be upheld if it achieves its purpose, even if the form is bypassed, provided it is not ad substantiam.
- Principle of Objective Good Faith (Art. 113, CC): Prevents a party from alleging the absence of written form (ad probationem) solely to evade obligations effectively contracted and executed.
In doctrine, the efficacy of Art. 227 of the CC is discussed in the face of the constitutionalization of Civil Law. Authors such as Flávio Tartuce and Anderson Schreiber argue that the value limit for testimonial evidence is anachronistic, and the judge should analyze the reliability of the evidence regardless of the economic value of the transaction, in observance of the principle of the search for the real truth.
6. Contemporary Relevance and Impacts on the Legal Order
The rise of digital relations has brought new contours to the topic. Law No. 14.063/2020, which provides for the use of electronic signatures in interactions with public entities and in health matters, reinforces the ad probationem nature of digital records. The electronic document, when a public deed is not required (ad substantiam), serves as robust proof of the manifestation of intent.
Practical relevance lies in strategic security: lawyers and legal consultants recommend written form even in non-solemn acts to ensure the pre-constitution of proof (titulus ad probationem), avoiding the insecurity of testimonial evidence, which is inherently volatile and subject to memory lapses or bias.
Legal and Jurisprudential References
- BRAZIL. Law No. 10.406, of January 10, 2002. Civil Code.
- BRAZIL. Law No. 13.105, of March 16, 2015. Code of Civil Procedure.
- BRAZIL. Superior Court of Justice. Special Appeal No. 1.834.401/RJ. Rapporteur: Minister Ricardo Villas Bôas Cueva. Third Panel. Decided on 12/15/2020.
- BRAZIL. Superior Labor Court. Precedent No. 12 (Effects of annotation in the CTPS - Relative proof).
- PONTES DE MIRANDA, Francisco Cavalcanti. Treatise on Private Law. Volume III. São Paulo: Revista dos Tribunais.
- DINAMARCO, Cândido Rangel. Institutions of Civil Procedural Law. Vol III. São Paulo: Malheiros.
