The Principle of Tax Simplicity

Normative Content, Conceptual Distinctions, and its Application

Abstract

This article examines the principle of tax simplicity introduced into Article 145, § 3, of the Federal Constitution by Constitutional Amendment No. 132/2023. Through a semantic and normative analysis, the study distinguishes between the concepts of simplicity and simplification and investigates the relationship between simplicity and tax practicability. It demonstrates that, while practicability serves the interests of the tax administration, simplicity guides the tax system as a whole, also serving to protect the taxpayer. The article draws upon the distinction between necessary complexity and avoidable complication – lconcepts from complexity theory applied to tax law – proposing that the principle of simplicity combats unnecessary complication in legal-tax relationships rather than the complexity inherent to the system itself. Finally, it examines the normative force of this new principle and two concrete cases for its application: the absence of the centralized calculation tool for the Difal (differential tax rate) provided for in Article 24-A of Supplementary Law No. 87/1996, and the calculation of the CSLL surcharge within the context of the OECD’s Pillar Two.