If I perform a sacramental rite exactly according to the rubrics, and use proper matter, but interiorly (and without any external manifestation) deliberately form a contrary intention not to do what the Church does, have I validly confected a sacrament?

"According to the almost general opinion of modern theologians", no, you would not have, at least as presented by Ludwig Ott in Fundamentals of Catholic Dogma.

However, let's keep in mind that we do seem to be in the realm of theological opinion, not dogma.

Ott initially presents what is de fide:
          a) For the valid dispensing of the Sacraments it is necessary that the minister accomplish the Sacramental Sign in the proper manner. (De fide.) This involves the obligation of using the essential matter and the essential form and of unifying them in a unitary sacramental sign. D. 695
          b) The minister must further have the intention at least of doing what the Church does. (De fide.) Ott explains "The expression 'To do what the Church does' (intendere facere quod facit Ecclesia) has been current since the beginning of the 13th Century".

Ott then discusses the necessity of the intention, and then the nature of the intention, and a mere external intention:

Nature of the Intention required in the Administration of the Sacraments.
Subjectively regarded, an actual intention is that disposition of the will which is present before and during the whole action, but such a disposition is not indispensable. A virtual intention, that is that disposition of the will, which is conceived before the action and which continues virtually during the action (called by St Thomas intentio habitualis), also suffices. An habitual intention, that is, that disposition of the will which was conceived before the action and which was not withdrawn, but which during the action is neither actually nor virtually present, and thus does not affect the action, is not sufficient.

Inadequacy of an intentio "mere externa".
According to the almost general opinion of modern theologians, an inner intention (intentio interna) is necessary for the valid administration of the Sacraments. By intentio interna is meant an intention which is directed, not merely to the external execution of the sacramental rite, but also to its inner signification. The mere external intention (intentio mere externa) which was regarded by many theologians of early Scholasticism, later by Ambrosius Catharinus, O.P. (+1553) and many theologains of the 17th and 18th Centuries, as adequate, and which is directed towards merely performing the external action whith earnestness and in the proper circuмstances, while the inner religious significance is not taken into consideration, is insufficient. The mere external intention is not compatible with the concept of doing what the Church intends, or with the status of the minister as a servant of Christ, or with the religious determination of the sacramental sign, which is of itself capable of many interpretations, or with the declarations of the Church. Cf D 424; fidelis intentio. Pope Alexander VIII in 1690 rejected the following proposition (...previously cited...) D 1318. Cf D 672, 695, 902. 

The necessary inner intention can be an intentio specialis et reflexa or an intentio generalis at directa, according to whether the inner religious significance of the sacramental action is intended in particular or only in general, whether with or without reflexion on the purpose and effects of the Sacrament.

So, the more common opinion of theologians on this matter of the intention required by the minister for valid administration of a sacrament seems to have changed from the older opinion, well-articulated by Ladislaus, of merely external intention sufficing, "doing what the Church does", to that more generally held now which requires an inner intention on the part of the minister, which adds "doing what the Church intends".

"According to the almost general opinion of modern theologians", no, you would not have, at least as presented by Ludwig Ott in Fundamentals of Catholic Dogma.

However, let's keep in mind that we do seem to be in the realm of theological opinion, not dogma.



So, the more common opinion of theologians on this matter of the intention required by the minister for valid administration of a sacrament seems to have changed from the older opinion, well-articulated by Ladislaus, of merely external intention sufficing, "doing what the Church does", to that more generally held now which requires an inner intention on the part of the minister, which adds "doing what the Church intends".

Plenus Venter-

A few points:

1) I agree with your response: A covert contrary intention invalidates the sacrament;

2) If it is true that this matter regarding covert contrary intention is not directly a matter of dogma (agreed), neither is it mere theological opinion (i.e., a debate among theologians regarding a subject upon which the Church has not ruled).  Pope Alexander VIII has ruled on the matter, according to the citation I have posted;

3) The position between older and more modern theologians has not changed.  The citations provided only state that there were more who shared Catharinus's position then than there are today, not that it was ever the prevailing opinion.

Canon George Smith seems to confirm the above explanation in "The Teaching of The Catholic Church":




In this sense, "doing what the Church does" means really wanting to do what the Church does by administering this sacrament (even if the effects of the sacrament are unknown to the minister who may not have the faith), not just performing the external rite as the Church prescribes. Can we all agree on that now?

Plenus Venter-

We are not discussing the efffects of the sacrament, but whether a valid sacrament is confected when the celebrant forms a covert contrary intention not to do what the Church does.

My contention (backed by Alexander VIII, l' Abbe Sylvester Hunter, and Msgr. Pohle so far) is that while the mere performance of the rite suffices for a presumption of validity, it does not supply for the requisite intention to do what the Church does. 

M. Ladislaus denies this, and while paying lip service to the need of interior intention, in the same breath says that so long as the rite has been performed, the sacrament has been confected.  Here is an example of him endorsing this opinion (See response #42 here):

"Yep.  In performing the ceremony, he was intending to DO what the Church DOES, and therefore validly confected the Sacrament."
https://www.cathinfo.com/index.php?topic=64616.30

My response to Meg above (from the manual of Msgr. Pohle) showed that while l' Abbe Hunter said this position was merely absurd in its theological consequences, Msgr. Pohle says that in the wake of Alexander VIII, this position is condemned. 

I've never said there needn't be internal intention, just disputing the nature of said intention.  You falsely claim that I hold that Catharinus opinion, which I do not, and then claim to know my motives for holding my position ... which is the correct one.

Au contraire.

See your response at post #42 here: https://www.cathinfo.com/index.php?topic=64616.30 

"Yep.  In performing the ceremony, he was intending to DO what the Church DOES, and therefore validly confected the Sacrament."

They don't.

If no one can determine a minister's inner intention, then how can it be used to determine whether his sacrament is valid?

Plenus Venter-

3) The position between older and more modern theologians has not changed.  The citations provided only state that there were more who shared Catharinus's position then than there are today, not that it was ever the prevailing opinion.

Actually, Msgr. Pohle speaks of a "tendency" in the primitive Church to hold every sacrament performed according to the prescribed rite as valid, without inquiring into the intention of the minister, which was always presumed to be right.  There then follows a list of theologians who rejected this doctrine, chiefly the Thomists, with it finally being overthrown at the Council of Trent.

See here, beginning at p.181: https://archive.org/details/sacraments01pohluoft/page/n189/mode/2up

It must be *considered* valid by all observers. In *actuality* it would be invalid.

Precisely.