Invincible Ignorance: A lack of knowledge for which a person is not morally responsible. For instance, if you were born in a remote region of Africa, and had never heard of Christianity (or Judaism), then you wouldn't be responsible for observing the third commandment (Keep holy the Lord's day). The reason you are not culpable for breaking the third commandment is because you could not possibly know of its existence. This is not the same as Christians who feign ignorance because they chose not to learn about God's commandments. It also does not apply to those who break the natural law (murder, theft, perjury, etc.) which all men can know through reason and adequate reflection.