While I do not support Ibranyi in most things, this is the most thorough treatment of the subject that I've found.
http://www.johnthebaptist.us/jbw_english/docuмents/books/rjmi/br45_ministers_intention.pdfIt's filled with citations and traces the entire history of the question.
This spin towards the subjectivized intention theory (internal vs. external is the wrong distinction) goes hand-in-hand with the subjectivism that eventually uprooted EENS dogma and lead to the subjectivist revolution at Vatican II.
I pick up a loaded gun, aim it at a person, and I pull the trigger, but I internally say "I do not wish this person to die," was there no intention to kill the person? Nonsense. By the very fact that the shooter intended to do the actions that would inevitably result in the death of the victim, he intended to kill the victim. If you intend the cause, then you also thereby intend the effect. So the shooter intended the death of the person. It matters not that he thought within himself, "oh, I hope this person doesn't die and don't want him to die."
Or it's like saying that I'm going to go about scrubbing my car with soap and water, but internally think, "I don't really want this car to be cleaned." But your'e doing the action that makes the car clean. So is it intended or not to clean the car? Which is the primary form of human intention and volition here, the performing of the action that causes the car to be clean or the idle (half insane?) thought that despite doing exactly what is required to clean the car, I do not wish for it to be cleaned?
I become intoxicated and sit down behind the wheel of my car and start driving. I have the thought, "I hope I don't kill someone in this state." Then I go and kill someone. I have committed the sin of murder. By intending the POSSIBILITY that I might kill someone, I intended the murder "in potentia", or in its cause even if I did not really want the end to happen on some EMOTIONAL level. Again, by intending the cause, you intend the effect. But the intellect and the will, by performing the cause, willed also the effect, all emotions aside.
When I am tempted to some sin, I can say inside, "I do not want to commit this sin," but then I go ahead and do it. It's ultimately in the DOING it that the will and intention manifest themselves. It's a human act of volition, despite the wishful thinking of not REALLY wanting it.
It's also like doing something while holding your fingers crossed behind your back, "see, I don't really mean to do this."
DOING it is proof of the pudding, so to speak. Intention is at the level of the will, not the emotions.
This is precisely what I liken the scenario of an infiltrator performing a Sacrament but then thinking inside, "I do not wish to perform the Sacrament."