Identidade e substitutividade a partir da lógica hegeliana da essência

This chapter aims first to present Hegel’s concept of identity in the “Doctrine of Essence” of the Science of Logic, and then to explore how Hegelian logic can contribute to understanding the problem of substitutivity. The analysis contextualizes identity within the history of philosophy and logic, outlining its formal characterization and limitations, and situates the substitutivity problem in debates initiated by Leibniz and further developed by Frege, who distinguished sense and reference to explain substitution failures in intensionally loaded contexts. The methodological approach is interpretative and analytical, based on a careful reading of Hegel’s text and conceptual analysis, using an example — the Masked Man Fallacy — to highlight the limitations of formal identity and unrestricted substitutivity. It is argued that Hegel’s distinction between abstract identity (formal and tautological) and concrete identity (reflexive and mediated by difference) allows for a reinterpretation of substitutivity failures as structurally necessary rather than exceptional. The chapter concludes that Hegelian logic provides a conceptual framework to understand identity as a dynamic process and to engage with contemporary issues in logic and philosophy of language.