How can we know what is and isn’t grave matter?

I understand that for a sin to be mortal, it must be grave matter (along with full knowledge and deliberate consent). How do we know whether something is grave matter or not? e.g. Would something going against the ten commandments be grave, while everything else wouldn’t be?

1 Like

The majority of sins are grave matter.

Foul language and small lies are the only things I can think of off the top of my head that aren’t grave matter.

1 Like

That which is inherently disordered gravely.

Think about the natural law, look into some catholic teaching regarding various sins, etc

1 Like

I had a spiritual advisor/confessor who was retired priest and Canon lawyer. He was very traditional, but he had a different view. He said he didn’t even like the mortal vs venial thing. He thought it was more for teaching a point to grade schoolers. He felt most sins were venial. Mortal sins had to be reserved for really serious stuff, stuff that would not likely be committed by the average practicing Catholic more than a very few times in their lives.

You can look to the Catechism, writings of the Doctors of the Church, and speak with clergy for clarification.

That doesn’t seem right. Masturbation is definitely grave and I don’t know anyone who hasn’t done it once

1 Like

So you have discussed masturbating with everyone you know otherwise how could you make such a claim. That includes your parents.

Masturbation is VERY common, and so are lustful thoughts.

And the Church explicitly defines both as grave matter.

I’m of the exact opposite mind - I think the majority of sins are grave, and only a few are venial.

That does NOT mean however the majority of grave sins commited are mortal, which I guess technically means they are still on the venial level.

It’s common knowledge.

I was in the military - I’d say 99% of guys I knew talked about boppin their baloney.


I laughed for a solid minute at this.


I have a simple answer, ask your Priest. He went to Priest training so he could answer


Many factors can mitigate the gravity of what would otherwise be a grave offence. Theft can be grave, but stealing something of minimal value with minimal harm to those involved probably isn’t grave.

I respectfully disagree, Spyridon. For the moment, I shall simply quote the CCC on the paragraphs that speak of “grave matter”.

1855 Mortal sin destroys charity in the heart of man by a grave violation of God’s law; it turns man away from God, who is his ultimate end and his beatitude, by preferring an inferior good to him.

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.

1862 One commits venial sin when, in a less serious matter, he does not observe the standard prescribed by the moral law, or when he disobeys the moral law in a grave matter, but without full knowledge or without complete consent.


According to polls, the majority of adults admit to masturbating. In secular circles, people openly talk about their masturbation habits.

Church doctors and clergymen don’t always agree on these things.

Here is one concise response from EWTN:

Yes the Commandments typically specify the matter of mortal sins.
Many other sins are traditionally subsumed under these Commandments.
eg fornication and masturbation and taking drugs are not there are they?

This is about natural Law, and we are capable of discerning it for ourselves for it is written in our hearts.

I suppose not. I’m not aware of any problems with determining gravity vs mortal or venial.

In the end all the above “grave matter” stuff are just analytical guides.

We are all called to regularly inspect our heart before God in quiet prayer.
(We are also called to keep educating ourselves about objective moral matters.)
Out heart will tell us when we have sinned gravely - regardless of splitting hairs on what constitutes objective grave matter.

We can of course sin mortally in matters that are not of objective grave matter.
In the end its how we perceived the matter at the time of the choosing and with how much certainty. If we thought it to be really serious but freely did it anyway…then that is a grave sin full stop.

We may later find out the matter was light (part of ongoing education) but that is not the point back then.

1 Like

Have you asked everyone you know? Some people (more likely women) have lower urges. Absent stimulating circumstances, eg in marriage, they simply lack the inclination/desire that might give rise to the thought to seek sexual release.

DISCLAIMER: The views and opinions expressed in these forums do not necessarily reflect those of Catholic Answers. For official apologetics resources please visit