So, does performing the externals of the rite prove the proper intention to do as the Church does?
No.
It suffices for the
presumption of a proper intention, but does not heal an invalidating covert contrary intention.
Were this not the case, intention need not be a criterion for a valid sacrament.
L' Abbe Hunter explains:
"The reply just given to the difficulty about the uncertainty of the Sacraments seems perfectly sufficient; but there have been theologians who, not being content with it, maintain the possibility of having absolute certainty that a Sacrament has been validly administered; and thus making some approach to the Lutheran assurance of the presence of habitual grace in the soul. This doctrine attracted attention at the time of the Council of Trent, being put forward by the Italian theologian, Ambrose Catharinus, who avowed that he was influenced by a desire to secure peace of mind to the faithful but one who feels a wish that a doctrine should be true may be suspected of not being a fair judge of the arguments bearing on it. The decree of the Council left the question open, and it is still debated, although the followers of Catharinus grow fewer in number and authority as time goes on.
“In the view of Catharinus, no other intention is required in the minister of a Sacrament than that he should deliberately go through the outward acts required by the rite; and this is held to be sufficient, though the minister have no interior intention of doing what the Church does, and even if he interiorly form an explicit act of not intending so to do. But this theory fails to secure the absolute certainty that the Sacrament is valid, for it is easy for the minister to change the words of the form (n. 680) in an essential particular without this fraud being detected.
“The theory, therefore, does not possess that advantage which was its chief recommendation, and it is open to grievous theological difficulties. The man who does not at least implicitly intend to act as agent for Christ cannot do so, for the character of his action depends on his intention; the words of the Council are most naturally applicable to the internal intention, and it is certain that this suffices; for if the matter and form of Baptism be duly applied to a child by one who interiorly intends to perform the Christian rite, the Baptism is valid, even though the minister pretend exteriorly that he went through the ceremony in mockery : and lastly, if the priest saying Mass intends to consecrate ten Hosts and no more, but has eleven before him, then not one is validly consecrated, as is declared in the rubrics of the Missal. (
De Defectu Intentionis.) For these and other similar reasons, most modern theologians reject the doctrine that the exterior intention is sufficient, but they confess that it has not been condemned by the authority of the Church."
L' Abbe Hunter then proceeds to cite the same quotation of Pope Alexander VIII which I supplied above.
Essentially, M. Ladislaus has rejected the need of interior intention, and espoused the views of Catharinus, apparently from a psychological need for infallible certitude in the matter of sacramental validity (which is imposssible to ascertain).