The principles of fungibility and conversion as mechanisms for correcting the improper choice of procedural remedies

Abstract

This article explores the possibility of overcoming the inadmissibility of appeals and the dismissal of independent collateral attacks arising from the improper choice of procedural vehicles. In light of the principle of instrumentality established by the 2015 Brazilian Code of Civil Procedure, it provides a critical reassessment of the requirements for the application of the principles of fungibility and conversion as corrective mechanisms for procedural inadequacy. The study argues that what is traditionally termed “fungibility” is, in fact, a form of conversion, as it presupposes the unsuitability of the chosen method and its subsequent adaptation to the correct one, refuting the notion of true indifference between procedural means. Consequently, it challenges the persistence of requirements such as “objective doubt” and the “absence of gross error”, advocating for a broader application of conversion as a technique for rectifying admissibility requirements. Finally, it proposes new criteria for its application: in appellate proceedings, the impermissibility of amending the grounds of appeal, in light of preclusion rules; and, in independent actions, compliance with the rules governing claim stabilization. Fungibility in its strict sense, in turn, remains limited to situations of objective doubt regarding the appropriate procedural avenue. In light of these considerations, the proposed reassessment contributes to the realization of the right to effective judicial protection by mitigating procedural barriers to the adjudication on the merits.