The presente thesis is primarily a work of jurisprudence whose object of research is the relationship between two strategies that the lawyer can use to solve problem of regulatory absence and/or insufficiency: analogy and extensive interpretation. Brazilian doctrine is unanimous in understanding that, despite the proximity, analogy and extensive interpretation are distinct strategies. The purpose of this thesis is to question this unanimity; therefore, it seeks to deepen the study of these strategies and investigate the relationship between them. Despite the existing conceptual difference and the distinction presente in the scope of criminal law – which admits the use of extensive interpretation, but not the analogy (except fot the benefit of the defendant) –, the boundary line that marks the scope of both is fluid and whit difficult practical application. Studies on these strategies end up prioritizing differences, neglecting the existing proximity between them. The thesis hypothesis: the key to understanding the relationship betweem analogy and extensive interpretation lies in what they have in common. This proximity is evidenced with the support of recente discoveries in the field of cognitive sciences, especially in studies on analogical reasoning.