From a reader…
Since latae sententiae excommunication is not incurred without committing a mortal sin, and acting against one’s conscience regarding something one thinks might be mortally sinful is itself a mortal sin, is excommunication incurred if one thinks one committed an excommunicable offense? For example: *possibly* having a particle of the Eucharist on one’s fingers, but washing it in a cup of water so the accidents change and *certainly* pouring it on the ground.
I guess another way to put it would be: does one have to certainly and actually complete the excommunicable act or is just thinking one completed the act grounds for excommunication? I can’t seem to find anything in canon law.
In order to incur an excommunication, you have to have committed a sin. You have to have known what you were doing was a sin and then willed to do it anyway. If you really don’t know, or you are truly in doubt, you don’t commit the sin or incur the censure. However, as it says in the Act of Faith, God can neither deceive nor be deceived. Mind games are dangerous.
That said, …
GUEST PRIEST RESPONSE: Fr. T. Ferguson
Canon 18: Laws which prescribe a penalty, or restrict the free exercise of rights, or contain an exception to the law are to be interpreted strictly.
The Church in her mercy and wisdom imposes the strictest of interpretations on penal law. For a person to incur a latae sententiae excommunication is, honestly, not an easy thing to do. One cannot incur such an excommunication casually or without knowledge. For an excommunication to apply, one must be cognizant that it is an excommunicatable offence and commit that offense willfully.
The law says, “A person who deliberately violated a law or precept is bound by the penalty prescribed in that law or precept. If however, the violation was due to the omission of due diligence, the person is not punished unless the law or precept provides otherwise.” (c. 1321, 2) and further, “No one is liable to a penalty who, when violating a law or precept was, without fault, ignorant of violating the law or precept; inadvertence and error are equivalent to ignorance.” (c. 1323, 2).
The Lord is Lord of our consciences and He cannot be mocked, so it’s good not to play the games we often play in our heads of trying to get as close to a violation of a moral law without going “past the boundaries,” but at the same time, He and His Bride, the Church, are wise and merciful. If you have doubt about a sin, it’s best to bring it to the confessional, but once absolved and forgiven, leave it there and move on.
Satan wants to keep us tied up fretting over past sins, God wants us to live freely and striving always towards Him.