Natual law and culpability for sin

Does a person who commits an action against the natural law but has no actual knowledge that something is a sin commit sin? For example, suppose a remote tribe with no outside contact has killed off the weakest individuals in the tribe every year for generations. Would a tribe member who partakes in the killings after being raised that way commit any sin?

Mortal sin is of grave requires full consent of the will and knowledge that it is gravely sinful. So it could still be sinful, but only venial.

If a protestant honestly believed that nothing was a grave sin because of God’s mercy would it be possible for that protestant to commit a mortal sin?

You bring up a good point. Have you done any reading on invincible ignorance? Definitely worth your time.

Depends on whether he’s invincibly ignorant or willfully ignorant. And for that, I leave for God to judge.

Thank you Eyesopening and BZkoss. I knew there had to be a little more to it than just knowledge.

1859 Mortal sin requires full knowledge and complete consent. It presupposes knowledge of the sinful character of the act, of its opposition to God’s law. It also implies a consent sufficiently deliberate to be a personal choice. Feigned ignorance and hardness of heart do not diminish, but rather increase, the voluntary character of a sin.

Apparently, the “hardness of heart” part could be stated as “knew or should have known.” Without this caveat, learned Catholics would be at a huge disadvantage in the struggle for eternal life compared to the masses.

In the case of seriously grave sin, a 1st world person with a sound mind could not be ignorant of the natural law against such sin regardless of faulty theology.

I am assuming you are saying this as being your own opinion. Or has the Church defined in more detail the meaning of willful ignorance to support your statement?

Not that my personal opinion is any different than yours. It kind of goes back to my original question relative to natural law. If certain things can simply be observed as moral or immoral than how could someone with a sound mind be ignorant?

The church maintains that ignorance reduces culpability.And yes, my opinion here is that any western-born human with a sound mind in the last many centuries would have a difficult time being ignorant of the evil of murder, human sacrifice, torture, etc, even regardless of any personally stated reasons denying this.

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