Well, sorry for any confusion, but this seems totally redundant to the good point japhy made, and my response. He pointed out, correctly, the one exception to what I was saying. But if you missed that, here goes again.
The “point Japhy made” was that you were wrong.
You answered the OPs question without knowing the answer. You responded with what you thought should be the answer rather than what was the correct answer.
You weren’t so quick to answer my question, though. I’m still waiting. You can’t be “redundant” because you’ve never answered the question; not even once–you’ve just avoided the question by claiming to have answered it, and playing word games.
So, what is a reasonable and just cause, in your experience, that would allow (routinely or otherwise) a priest to celebrate Mass without another minister present as required/suggested by the GIRM?
Thanks so much for your patience, sorry to try it so.
Your “one exception” is quite common.
Here are plenty of just causes:
Two priests at one parish. One says the public Mass, another says a private Mass.
The priest’s day off, and no Mass is scheduled in the bulletin.
The priest is on vacation. (example: he’s gone on a 4 day camping trip alone.)
The priest is travelling for some reason, and doesn’t know anyone who is available at the same time he is.
The priest gets a phone call that a relative/friend had died and walks to the Church to say a private Mass
The priest schedules a daily Mass, but no one shows up (happens a lot in small parishes)
The priest is ill and can’t celebrate a public Mass. Happens a lot in hospitals, nursing homes, and priest retirement homes.
The priest is retired, has no parish, and yet still says a private Mass every day.
The altar boy who was supposed to serve never shows up for some reason.
The priest is unable to attend a community Mass (like a priest retreat or a community Mass in a religious house), and says a private Mass at his own convenience.
The priest asks around, but no one is available to be there when he says Mass–happens a lot at places like chanceries and large parishes where there are already many Masses happening that day.
A priest who doesn’t speak the “local” language–like a Spanish speaking priest who is “in residence” at an English speaking parish but covers the Spanish Masses in another town on Sundays, and says a private Mass in Spanish on the weekdays.
A priest who wants to say a Mass for a deceased relative, and wants a little “privacy” at the moment.
Priests in a seminary, where all the seminarians are required to attend the community Mass, but the priests not celebrating that Mass each say a private Mass while the students are in class.
The priest doesn’t feel like attending the parish daily Mass because the other priest preaches too long. He says a private Mass instead, but avoids scandal by not telling anyone else.
If you need some more examples of a just cause,
I’ll be happy to provide them from actual real-life experience, in contrast to merely guessing and getting it wrong.