In a synthetic way, it can be said, on the one hand, that good faith is a legal requirement imposed by the need to prevent an obligation from serving to achieve intolerable results for people of reasonable conscience. And, on the other hand, one acts in good faith when doing so with diligence, zeal, and loyalty corresponding to the legitimate interests of the counterpart, through honest and conscientious conduct, with correctness and probity, without harming the legitimate interests of the other party or acting in a way to achieve results not tolerable by a reasonable conscience. 

Under the provisions of Article 334 of the Civil Code, the exercise of a right is illegitimate when its holder manifestly exceeds the limits imposed by good faith, good customs, or the social or economic purpose of that right. This article refers to the existence of a substantive right exercised with manifest excess in relation to the limits arising from its social or economic purpose, contrary to good faith or good customs, essentially prohibiting the use of the power contained in the structure of the right to pursue interests exorbitant to the purpose inherent to it.

The understanding of jurisprudence, following doctrine, has been that this institute functions as a limit to the exercise of rights when the attitude of its holder manifests itself in behavior offensive to the ethical-legal sense of the generality of people in terms clamorously opposed to the dictates of loyalty and correctness prevailing in the legal order. 

One of the aspects of the abuse of rights is the so-called venire contra factum proprium, in confrontation with the principle of the protection of trust, as is the case of being exercised against someone who, based on convincing conduct, positive or negative of the one who could exercise it, trusted that such exercise would not occur and planned their activity accordingly.

It can be said, in this hypothesis, that the holder of the right operates its exercise in confrontation with another after making them believe, by words or actions, that it would not be exercised, that is, after generating an objective situation of trust that it would not be exercised.

Thus, both in the negotiation/formation and in the fulfillment/execution of contracts and, likewise, in the exercise of corresponding rights (namely, the right to terminate the contract), the parties must conform to the principle of good faith (cf. Articles 227, paragraph 1, and 762, paragraph 2, both of the Civil Code, respectively), adopting, in this context, honest, correct, and loyal conduct, and, moreover, committed not only to the trust generated in the counterpart (with corresponding investment by the latter), but in general with the contractual interest of both parties (that which they aim to achieve/satisfy with the fulfillment of the business), so that the contractual interest of either party is not unnecessarily and intolerably harmed/compromised.

The principle of good faith reveals certain objective behavioral requirements imposed by the legal order, these requirements of reasonableness, probity, and balance of conduct, in normative fields where sub-principles, rules, and dictates or objective limits can operate, indicating a certain mode of action of the subjects, considered in accordance with good faith, which must be present in the scope of evaluative and applicative tasks to concrete cases, taking into account the nature and socio-economic function of the contract [cf. also Menezes Cordeiro, Tratado de Direito Civil Português, I, volume I, Almedina, Coimbra, 1999, p. 18; cf. Judith Martins-Costa, Os campos normativos da boa-fé objetiva: as três perspectivas do Direito privado brasileiro, in Estudos de Direito do Consumidor, Centro de Direito do Consumo, no. 6, 2004, p. 105. ([23]) cf. Sinde Monteiro, Responsabilidade por Conselhos, Recomendações ou Informações, Almedina, Coimbra, 1989, p. 165], to which it is intended to apply and the legal relationship established between the parties. 

In this path, the relevant role of the principle of good faith is evident, sometimes founding, especially in situations of inequality between the parties, namely when one of them is subject to an informational deficit, the legal imposition of duties of information, but also of loyalty and protection, from one party to the other, in order to safeguard the contractual purpose envisaged by the latter – here the principle of good faith “constitutes the legal foundation”, while the “material foundation” is found “in the inequality or imbalance of information” (this of a technical and complex nature), in a situation of “particular need for protection” of one of the interlocutors [cf. Sinde Monteiro, Responsabilidade por Conselhos, Recomendações ou Informações, Almedina, Coimbra, 1989, p. 165 and 360], with the aim of, as far as possible, ultimately compensating, in substantial terms, that previous inequality.

It is well understood, therefore, that in the context of civil relations and, even more so, in commercial ones, where individualism predominates to some extent, opening horizons through the conforming influence of the principle of contractual freedom, each party in contracts acts in a way to obtain for themselves, within the limits of the law, the maximum possible advantages or utilities, without worrying about the interests of the other party, which may, therefore, be subordinated or even rendered unfeasible. This can lead to a manifestly unbalanced outcome of the contractual relationship, given the purpose of the contract. However, sometimes a different relational atmosphere emerges, where the contractual field opens up as a space for new interpenetrations of interests, with innovative perspectives on the rights and duties of each party, where ethical-legal postulates of loyalty, correctness, honesty, and even solidarity, co-responsibilize all contracting parties in carrying the established long-term relationship to its end, through paths of reasonableness, balance, and maximum possible common benefit. – Cf. Ac. TR de Coimbra, Proc. no. 896/13.6TBCTB.C1, of 04/04/2017.

In this context, there will no longer be room for strict individualistic selfishness, where each party only cares about themselves, in obtaining and consolidating all their interests motivating the contract, if necessary, at the total sacrifice of the contractual purpose of the other party. Instead, there will be a new paradigm for the entire path of executing the contractual pact, already subject to the demands of unavoidable ethicalization, where the overall goal of the intended contractual relationship is only achieved when both parties manage to extract, once fully executed, the minimum expected utilities, reciprocally and commonly accepted as the intended outcomes of the contractual program. Therefore, the parties, who joined in the common celebration of the contract, instead of opposing each other in the exclusive pursuit of their own selfish interests, are called to cooperate, co-responsibilizing themselves, in imprinting a direction of long-term contractual execution that, in a balanced way, can yield the typical expected contractual fruits for both, in a materially fair settlement of the established relationship. – Cf. Ac. TR de Coimbra, Proc. no. 896/13.6TBCTB.C1, of 04/04/2017.

In this perspective of ethicalization within the scope of Contract Law, the importance of the principle of good faith is evident, as an essential and irreplaceable vehicle for concretizing the ethical-legal postulates of the system, imprinting such an ethical dimension, dominant in our legal order. – Cf. Ac. TR de Coimbra, Proc. no. 896/13.6TBCTB.C1, of 04/04/2017.

The mechanisms that can currently be used in this context, aiming to project the necessary ethical-legal valuations onto the various dimensions and phases of the contractual relationship, through the concretizing mediation of objective good faith, are several. Among them is the protection of trust, which has well-defined assumptions in doctrine, due to marked Germanic influence, and is accepted in jurisprudence. Indeed, it is agreed that the legal protection of trust always implies: a) a situation of trust, in accordance with the system and translated into subjective and ethical good faith, characteristic of the person who, not violating the duties of care imposed on them by the circumstances of the case, is unaware of harming the rights of others or any other positions; b) a justification for this trust, expressed in the presence of objective elements capable of, in abstract, provoking a plausible belief, according to the standard of a normal person; c) an investment of trust, consisting of the trusting party having effectively based their legal activities on the substantiated belief; d) the imputation of the created situation of trust to the person who will be affected by the protection granted to the trusting party – such person, by action or omission, will have given rise to the trust or the objective factor that led to it (Cf. Menezes Cordeiro, Tratado de Direito Civil Português, I, volume I, Almedina, Coimbra, 1999, p. 186 et seq.; Cf. – Cf. Ac. TR de Coimbra, Proc. no. 896/13.6TBCTB.C1, of 04/04/2017.)

In turn, another of those mechanisms, the so-called principle of the primacy of underlying materiality – focused on the projected contractual purpose – is based on the idea that Law aims to achieve effective solutions, not being satisfied with appearances, such as the mere adoption of conduct only formally in line with legal objectives, but rather requiring conformity on a material, substantial level. Legal exercises should be evaluated, according to good faith, in material terms, according to their actual consequences. Hence the primacy or priority for legal solutions of materiality or substance – material justice – instead of merely formal solutions (of merely formal justice), requiring balance/proportion in the exercise of legal positions, postulating the need to scrutinize conduct, even if permitted, in light of the system, prohibiting gratuitously harmful actions to others or those that are severely unbalanced – conduct that, in view of a minimal advantage for oneself, causes maximum harm to others. – [Cf. Menezes Cordeiro, Tratado de Direito Civil Português, I, volume I, Almedina, Coimbra, 1999, p. 186 et seq.; Cf. – Cf. Ac. TR de Coimbra, Proc. no. 896/13.6TBCTB.C1, of 04/04/2017.]

M. Amélia Cruz