Understanding Mortal Sin?

The qualifications for mortal sin set forth by the CCC are as follows:
•Mortal sin is a sin of grave matter
•Mortal sin is committed with full knowledge of the sinner
•Mortal sin is committed with deliberate consent of the sinner

My question is…What is “full knowledge?” The reason I ask is because many Catholics commit acts that they know the Church says is wrong but that they believe isn’t wrong…So if a person truly believes an act is not sinful, does he or she still commit a mortal sin?

For example,
If a 17-year-old boy who has grown up in Catholic schools all his life and has been told pornography is sinful simply doesn’t believe the Church is right about pornography. Is he committing a mortal sin here?

(By the way, since I know this will come up if I don’t address it…I don’t watch pornography BECAUSE I believe it is sinful.)

If a person genuinely and sincerely does not recognize the sinful nature of the act then it is not mortally sinful. But, porn? c’mon! The Church also teaches:

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. [CCC 1859, emphasis mine]

I think there’s some self-serving hardness and feigning going on here. But only God knows for sure.

Think what you want…But I am not interested in looking at pornography. That’s a pretty insulting thing to say by the way…

I am trying to understand what mortal sin is. My issue is really papal/church infallibility

Some people try to make out full knowledge is complicated and that they cannot possibly have FULL knowledge about anything and so they cannot commit a mortal sin. This is simply a means for people to justify continuing to sin.

If a Catholic knows that the Church teaches certain acts are sins of grave matter then that satisfies the condition.
Whether a Catholic then believes the Church teaching is wrong does not negate the knowledge so such a person by committing an act he knows to be of grave matter would be committing a mortal sin.

If a Catholic believes that the Church is the true (and only) Church established by Christ to which he gave teaching authority in matters of faith and morals then such Catholics must believe that the Church cannot err in its teachings. The two go hand in hand. You cannot believe the Church is the true Church and at the same believe a teaching can be/is wrong.

Now if a Catholic knows what the Church teaches but does not understand the teaching then the onus is on that person to study and look into the teaching to try to understand it but if the result is that they still cannot understand then they must accept it.

I hate being legalistic ;), but I think this would be a good analogy.

In criminal law, most crimes consist of two elements:

mens rea - A mental state.

actus reus - An act.

So we commit a crime, when we are on a mental state and we act on it. The severity of the crime is dependent on the degree of the mental state and the degree of the act.

A mortal sin, is a sin *done *in full *knowledge *of it being a grievous offense against God.

The CCC says about sin:

1850 Sin is an offense against God: "Against you, you alone, have I sinned, and done that which is evil in your sight."122 Sin sets itself against God’s love for us and turns our hearts away from it. Like the first sin, it is disobedience, a revolt against God through the will to become "like gods,"123 knowing and determining good and evil. Sin is thus "love of oneself even to contempt of God."124 In this proud self- exaltation, sin is diametrically opposed to the obedience of Jesus, which achieves our salvation.125

A mortal sin is what St John talks about in 1 John 5:16 If any one sees his brother committing what is not a mortal sin, he will ask, and God will give him life for those whose sin is not mortal. There is sin which is mortal; I do not say that one is to pray for that. 17 All wrongdoing is sin, but there is sin which is not mortal..

Further, the CCC says:
1857 For a sin to be mortal, three conditions must together be met: "Mortal sin is sin whose object is grave matter and which is also committed with full knowledge and deliberate consent."131


You have correctly cited the teaching of the Church regarding mortal sin. The Church cannot and does not infallibly say whether any particular offense (no matter what it is) is categorically mortally sinful.

Since the Church makes no infallible claim to determine the mortal nature of any particular sin, I don’t think your issue is really to determine papal/church infallibility. Neither the Pope nor the Church can infallibly determine the mortal nature of any particular sin. If I murder somebody, it is absolutely beyond the competence of the Pope or the Church to positively determine whether or not I have committed a mortal sin (if I happen to murder a Pope then I am automatically excommunicate, but that’s far from the same thing). This limitation is actually Catholic Doctrine.

That’s like the person who goes 100mph through town. They believe it’s okay even though they know the posted speed limit is 35mph. Did they break the speed limit? Will the cop who pulls them over and arrests them on the spot, care WHAT that person believes he can do?

Cops aren’t always around. God is. And mortal sin is clear. #15

the CCC and scripture views all these sins as grave / mortal / sins #15 , 1856

Jose, I think your response is quite good…but my question is actually about the mental state. When is “knowledge” said to exist? Is “full knowledge” awareness of the teaching of sin or the acceptance of sin? In other words, if a 17-year-old boy knows that pornography is said by the church to be a sin, but doesn’t believe the Church is right (in other words, he doesn’t believe pornography is a sin), is he said to have knowledge?

In law, since you brought that up, one is said to have sufficient “knowledge” regardless of whether or not he or she believes the law is valid.

Way too much of a slippery slope here, since some Catholics/Christians
actually believe something like “David” by Michaelangelo is Pornography, or
that any tasteful or artistic Nude photo/Sculpture is porn, which it is NOT>

I apologize…I wasn’t trying to say that my question about mortal sin has some connection to church infallibility - I was simply saying my “issue” with the Church is infallibility. For me, that is the primary problem I have. It’s not about mortal sin. You seemed to suggest I was trying to find a way around a Church teaching, so I was responding to that by saying, “Actually, my problem with the Church is something completely different.” I didn’t do a good job of expressing that in that post, but that’s what I was getting at.

Although I appreciate the analogy, I am not sure it’s really similar at all. By your logic, the “full knowledge” requirement is thrown out the window. All that matters is that a person is committing a sin. What that person knows about the sin is meaningless in your analogy, and the Church specifically says that your formulation is wrong. Intent does matter…a great deal.

I am not sure legal analogies make no sense, because in law, intent matters far less than it does in religious matters, where motive is a huge part of the equation.

Pornography is just an example…I am trying to understand, or “get at,” the heart of mortal sin. Is it about following rules or deliberately disobeying God…For me this is a major issue…because if the Church says, “It doesn’t matter if you think it’s a sin or not so long as you have been told it is,” then you are essentially making faith in the Roman Catholic Church more important than faith in Jesus Christ. There’s no way around that. Rules are now more important than faith - something Paul SPECIFICALLY rejected.

However, if the issue is deliberately opposing God, then the teaching on mortal sin makes a lot more sense within the context of Paul’s teachings.

The teenager, in thinking that the Church is wrong, is placing himself above the Church. But I see what you are saying in regards to this specific person (a teenager). I think I can say with certainty that almost all of us have been in that rebellious stage and think of ourselves to know better than any person/institution in authority, lol.

I guess it would depend on the maturity of the teenager in question. Has he been told several times by the Church and his parents that pornography is wrong. Does the teenager understand why it is wrong (Heck, there’s a lot of adults that disagree as well, lol). So I think that full knowledge has to be accompanied by full understanding as well. Also we need to know if the teenager is already in a habitual state in regards to this sin. The adult/Church intervention only came after he/she was able to develop this sin into a habit. Which will make it much harder to break.

On the other hand, if the teenager is just being obstinate about it. Then, yeah, it would be mortal.

Mortal sin is when you know it is a grave sin and you do it anyway. It isn’t all that complicated or philosophical. You either know it is a sin or you don’t. It is really difficult to assess if someone else is in mortal sin precisely because we don’t know “how much they know”. Thankfully, its not our job to judge a soul; God knows and He will be the judge. But I always know when I have committed a mortal sin.

Here are some points from the Catechism.

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**.

1860 Unintentional ignorance can diminish or even remove the imputability of a grave offense. But no one is deemed to be ignorant of the principles of the moral law, which are written in the conscience of every man. The promptings of feelings and passions can also diminish the voluntary and free character of the offense, as can external pressures or pathological disorders. Sin committed through malice, by deliberate choice of evil, is the gravest.

Oh and this one is interesting too-- spot on with the Scriptures that talk about correcting our brother.

1868 Sin is a personal act. Moreover, we have a responsibility for the sins committed by others when we cooperate in them:

  • by participating directly and voluntarily in them;

  • by ordering, advising, praising, or approving them;

  • by not disclosing or not hindering them when we have an obligation to do so;

  • by protecting evil-doers.

knowledge is not thrown out the window. It’s illegal for one to drive without a liscence, and a liscence presumes one has passed a drivers test informing them of the laws of the road.

Take for example a person who commits fornication or adultery. Aside from a gun to someone’s head, what is the intent and motive behind one committing those sins?

On the act, when parties commit those sins, their intent to do it was there.

On the act, when parties commit those sins, how could one argue motive was not there as well?

Hey Jose,
This is where things get complicated for me regarding mortal sin. If disobeying the Church’s teaching on something is the sole reason for a person having mortal sin and therefore going to hell, then people who FULLY believe in God, Jesus, and who engage in the sacraments…People who love, and are kind, and give to the poor, and otherwise live saintly lives, are damned to hell for disagreeing with a teaching the Church says is true but is something the individual doesn’t believe. Is that really and truly turning one’s back against God? If someone honestly disagrees…how can that be grounds for hell?

This effectively puts faith in the Church as MORE important than faith in Jesus Christ. In the Bible, whenever anyone is saved by Jesus, it’s only after they express faith in some way. Jesus never makes them go through a laundry list of other teachings to make sure they have it all “right.” They are saved because of their faith and willingness to express that faith. Faith in Jesus effectively doesn’t matter if you can be damned for hell for disagreeing about some Church teaching that isn’t clearly laid out by Jesus or the Apostles in scripture.

That’s why this thread is so important to me…because to me, it’s at the heart of salvation. What is more important? Faith in Jesus or faith in the Church authorities? If faith in Jesus cannot even overcome a lack of faith in some particular and confusing Church teaching, then what are church authorities really saying here?

All good points! But the real issue is…When is “knowledge” established? When a person truly knows something is wrong or when a person “ought to know”? I am getting two different answers regarding this.

Why make this an either / or?

Didn’t Jesus say, “I will build my Church and not even the gates of hell will prevail against it”?

Do you believe that?

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