Question about what counts as a mortal sin

[LivingForJesus]

I have trouble defining what counts as a mortal sin. This is the definition I found online…
“There are 3 conditions that need to be met for a sin to be mortal…
Grave Matter: The act itself is intrinsically evil and immoral. For example, murder, rape, incest, perjury, adultery, and so on are grave matter.
Full knowledge: The person must know that it is evil and is a grave matter
Deliberate consent: The person must freely do it.”

My problem is that this definition seems way too narrow. I understand the 1st and 3rd condition but I do not really understand the 2nd. If it really doesnt count as a mortal sin if the person didnt know it was a grave matter than that would mean that it would be better not to tell other people that it is a grave matter in order for them not to be commiting a mortal sin. Think about it. This means that a person masturbating not knowing that it is a grave matter is only commiting a venial sin, and that us telling them that it is a grave matter would make it a mortal sin, giving them a larger burden. Also, this would restrict people who are in a state of mortal sin to be very few, but the Church fathers have taught over and over again that the majority of people are damned and are in a state of mortal sin. I just really don’t know how all this would work.

These are really just my thoughts, and I know deep down that this can’t be true. I genuinely hope that someone out there can respond to my questions/thoughts on this. Thank you.

 

[KevinK]

This is similar to the reasoning that it is better to not evangelize people because now you have the risk of them rejecting it and going to hell, instead of remaining without full knowledge and having a hope of salvation. I don’t have a good answer.

 

[Bluebright]

Well the idea of telling people, is that they stop doing ‘the grave matter’ and repent. Thereby being free of either a mortal venial sin and being in a state of grace and potentially staying in a state of grace by receiving the Eucharist at mass regularly which would remove venial sins. They can also pray and practice devotional confession and grow closer to God. That’s the point of telling them about sin, also it’s the little thing of being a spiritual work of mercy - which we should do. You can’t necessarily coast into heaven without the Eucharist and on just ‘being a good person’. You need the Eucharist and Confession as well as Baptism ie. the sacraments.

 

[Vico]

…

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 heart133 do not diminish, but rather increase, the voluntary character of a sin.

1790 … Yet it can happen that moral conscience remains in ignorance and makes erroneous judgments about acts to be performed or already committed.

1791 This ignorance can often be imputed to personal responsibility. This is the case when a man "takes little trouble to find out what is true and good, or when conscience is by degrees almost blinded through the habit of committing sin."59 In such cases, the person is culpable for the evil he commits.

St. Pope John Paul II wrote:

70. The Post-Synodal Apostolic Exhortation Reconciliatio et Paenitentia reaffirmed the importance and permanent validity of the distinction between mortal and venial sins, in accordance with the Church’s tradition. And the 1983 Synod of Bishops, from which that Exhortation emerged, “not only reaffirmed the teaching of the Council of Trent concerning the existence and nature of mortal and venial sins, but it also recalled that mortal sin is sin whose object is grave matter and which is also committed with full knowledge and deliberate consent”.[116]

The statement of the Council of Trent does not only consider the “grave matter” of mortal sin; it also recalls that its necessary condition is “full awareness and deliberate consent”. In any event, both in moral theology and in pastoral practice one is familiar with cases in which an act which is grave by reason of its matter does not constitute a mortal sin because of a lack of full awareness or deliberate consent on the part of the person performing it. Even so, “care will have to be taken not to reduce mortal sin to an act of ‘fundamental option’ — as is commonly said today — against God”, seen either as an explicit and formal rejection of God and neighbour or as an implicit and unconscious rejection of love. “For mortal sin exists also when a person knowingly and willingly, for whatever reason, chooses something gravely disordered. In fact, such a choice already includes contempt for the divine law, a rejection of God’s love for humanity and the whole of creation: the person turns away from God and loses charity. Consequently, the fundamental orientation can be radically changed by particular acts. Clearly, situations can occur which are very complex and obscure from a psychological viewpoint, and which influence the sinner’s subjective imputability. But from a consideration of the psychological sphere one cannot proceed to create a theological category, which is precisely what the ‘fundamental option’ is, understanding it in such a way that it objectively changes or casts doubt upon the traditional concept of mortal sin”. [117]

https://w2.vatican.va/content/john-...hf_jp-ii_enc_06081993_veritatis-splendor.html