How does one explain this, then?
“A materially venial sin cannot be formally mortal. Thinking that a sin is mortal does not make it so! For there to be mortal sin, there needs to be grave matter (CCC 1857–59). This, too, is freeing for the scrupulous person who mistakenly thinks all sin is mortal.”
If “unsure mortal sins” are mortal, that pretty much would put the nail in the coffin, so to speak, for scrupulites. If they are to speak with their confessors to fix everything, they will need to go at least a couple times a day, right?
The “thing itself” that is “venial matter” does not
become grave matter…that is not the grave matter here it does not “morph”. It is rather that the person has say good reason to think it may be grave matter (like a serious reason) and does not take the reasonable means etc to find out before he does it. It is like he says “I do not care…that it may be mortal …I am just going to do it”.
To use the classic example…a hunter sees something moving up ahead…and he is not sure if it is a deer or his friend…he needs to wait until he has more certainty before he shoots. If he pulls the trigger with full knowledge and deliberate consent …such can thus be a Mortal sin …even if it turns out to be a deer (the grave matter here would be shooting while not knowing if it is a deer or another hunter) (now I am not a hunter…but this is one of the classic examples.)
Now a person with a difficulty with scrupulosity…may have some fear or thought when looking at a deer that …hum what if this deer is some child’s pet that got loose and if I kill it it will gravely hurt the child…or they might fear right as they are pulling the trigger…what if someone is just wearing a deer suit to play a joke on me…and then worry that they committed a mortal sin…
As I noted there…those with scrupulosity or scruples…are often in a very different boat that others…(Hence my hesitation in even answering the original question)…(they often have a great difficulty in this area…fearing this or that is mortal sin …they need to follow their confessors/directors and the principles given them…they can then act against their fears…their scruples…(their unreasonable unsureness) and not sin…for they are in a different boat and have formed their actual conscience by the advise of their confessor and the general principles they are to follow…(to follow in life)
Hence they have historically been told often by their confessors etc to say only take “complete certainty” into account…and to ignore the doubts that bother them…things like that…and thus they would tell them thatthey can not commit a mortal sin unless they are
certain that it is grave matter and that knowing this they go ahead and do it anyway. Things like that (to give one example). The confessor will know the penitent and thus can advise him personally…as to what to follow.
(for they generally know things that would really be grave…and would be certain about them…)
It is very important that they have a regular confessor who can tailor his advice to their particular difficulties…and to help them with some* general principles* they are to follow
Of course such principles would be only given to those with scruples to one degree or another…for as I noted they can be in a different boat…they mistake all their fears etc for what they are not…and they are in danger of never acting…or doing themselves harm etc… a confessor can thus give them general principles to follow 24-7…and can then of course also answer questions and help them form their conscience.