2020-01-152020-01-152008SANZ, Wagner Campos. Falsity preservation. CLE e-Prints, Campinas, v. 8, n. 2, p. 1-14, 2008.e- 1519-9681http://repositorio.bc.ufg.br/handle/ri/18514In the following paper we examine falsity preservation phenomena for natural deduction and axiomatic logical systems. We start with Syllogistics and end with a very interesting form o Peano Arithmetic for Refutability in which Gödel’s Incompleteness Theorems hold. The paper presents valid syllogistic moods of falsity preservation based on valid moods for truth preservation and also valid rules of falsity preservation in natural deduction. That such systems can be defined is surprising, but that they resemble truth preservation system is remarkable. That put us in front of an important question: what means do we have to distinguish truth and falsity from a logical point of view?engAcesso AbertoFalsity preservationSyllogisticNatural deductionDe Morgan’s lawsPeano arithmeticIncompletenessNegationArtigo