The invincible ignorance fallacy is a deductive fallacy of circularity where the person in question simply refuses to believe the argument, ignoring any evidence given. It is not so much a fallacious tactic in argument as it is a refusal to argue in the proper sense of the word, the method instead being to make assertions with no consideration of objections.
The term "invincible ignorance" has its roots in Catholic theology, where — as the opposite of the term vincible ignorance — it is used to refer to the state of persons (such as pagans and infants) who are ignorant of the Christian message because they have not yet had an opportunity to hear it. The first Pope to use the term officially seems to have been Pope Pius IX in the allocutionSingulari Quadam (9 December 1854) and the encyclicalsSingulari Quidem (17 March 1856) and Quanto Conficiamur Moerore (10 August 1863). The term, however, is far older than that. Aquinas, for instance, uses it in his Summa Theologica (written 1265–1274), and discussion of the concept can be found as far back as Origen (3rd century). When and how the term was taken by logicians to refer to the very different state of persons who deliberately refuse to attend to evidence remains unclear, but one of its first uses was in the book Fallacy: The Counterfeit of Argument by W. Ward Fearnside and William B. Holther.