As a teacher, I am always pained when I hear “ignorant” used as an insult.
ignorance: n. lack of knowledge
Everyone is born ignorant into the world. The word ignorance is from Latin ignorantia. The prefix in– means “not”; Old Latin gnarus means “aware, acquainted with.” Mere ignorance is nothing to be ashamed of. Ignorant is not a synonym for “stupid.”
Catholic theology recognizes three categories of ignorance:
invincible ignorance: lack of knowledge that a person has no way to obtain
vincible ignorance: lack of knowledge that a rational person is capable of acquiring by making an effort
nescience: lack of knowledge that doesn’t matter in the circumstances (from Latin ne-, “not” plus scire, “to know.”
In Catholic theology, invincible ignorance, “whether of the law or the fact, is always a valid excuse and excludes sin.”
In the secular realm, however, all ignorance is seen as “vincible.”
For logicians, the term “invincible ignorance” means “the fallacy of insisting on the legitimacy of one’s position in the face of contradictory facts.” If the facts are presented, there’s no excuse to refuse to acknowledge them.
The law likewise does not allow for a category of information unavailable to the lawbreaker that would forgive the breach of the law: ignorantia juris non excusat, “ignorance of the law does not excuse.”
Here’s a lengthier definition of the secular take on invincible ignorance from Wikipedia:
invincible ignorance: a deductive Fallacy of Circularity where the person in question simply refuses to believe the argument, ignoring any evidence given. It’s 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.
Fitness expert Greg Glassman has this recommendation for dealing with invincible ignorance:
some simply cannot be swayed toward your way of thinking, so don’t try. …you’re probably best to walk away from a pointless debate.