The proof is undoubtedly the most important tool put to the knowledge of the judge to determine the conviction and, from there, set within the normative criteria, who must be ensured clamada justice. This thesis proposes a dogmatic and empirical investigation of the applicability of the evidence in the tax process, whether administrative, or judicial, demonstrating its power as a means rhetorical for through the defense of the legal truth and the use of language as training of the instrument knowl edge, convince the state judge the validity of propositions brought in the process. It also aims to demonstrate the limits of application of the presumptions in tax matters, with an emphasis on tax planning and the position adopted by the administration and
the judiciary on issues involving the tax liability of companies perceived as economic group.
