No, "et" is not "stronger".  "ut" clearly indicates that the ordination is the Sacramental effect from the invocation of the Holy Ghost.  Without it, these are two separate prayers.  "May the Holy Ghost descend upon him.  May he become a priest." (paraphrased).  Traditional Rite has it, "May the Holy Ghost descend upon him in order to make him a priest."  Those are significantly different prayers.  You could argue that this is implied in the newer version, but I submit that it's implied only because someone who's familiar with the Traditional predecessor of this prayer would READ this into it.  But if you knew nothing about the former version, you could clearly read this as invoking the Holy Ghost to PREPARE the individual for reception of the priesthood, and then asking for it to be conferred.  They are logically different constructs and therefore suffice to introduce at least a positive doubt.

You seem to be just making this up that "et" is "stronger for validity".  Clearly the "ut" in Latin means something, a cause and effect relationship, which is simply not explicitly there in the new rite.

I pray for A to cause B.
I pray for A.  I pray for B.

Logically two different things.  Ergo, positive doubt.  It's morally certain that this introduces positive doubt.

No, "et" is not "stronger".  "ut" clearly indicates that the ordination is the Sacramental effect from the invocation of the Holy Ghost.  Without it, these are two separate prayers.  "May the Holy Ghost descend upon him.  May he become a priest." (paraphrased).  Traditional Rite has it, "May the Holy Ghost descend upon him in order to make him a priest."  Those are significantly different prayers.  You could argue that this is implied in the newer version, but I submit that it's implied only because someone who's familiar with the Traditional predecessor of this prayer would READ this into it.  But if you knew nothing about the former version, you could clearly read this as invoking the Holy Ghost to PREPARE the individual for reception of the priesthood, and then asking for it to be conferred.  They are logically different constructs and therefore suffice to introduce at least a positive doubt.

You seem to be just making this up that "et" is "stronger for validity".  Clearly the "ut" in Latin means something, a cause and effect relationship, which is simply not explicitly there in the new rite.

I pray for A to cause B.
I pray for A.  I pray for B.

Logically two different things.  Ergo, positive doubt.  It's morally certain that this introduces positive doubt.

So Plentus, would you say that since the Church has never solemnly defined that she can only publish and impose valid sacramental rites, we must leave open the possibility that she can publish and impose invalid sacramental rites?

It’s NOT making your “own dogmas”, it’s calling using your God given brain and making logical conclusions AFTER following the teachings of the Church and consulting Her theologians. We are simply applying what the Church teaches to our given situation *without* binding someone else’s conscience.

I would say Sedevacantism does not follow the teachings of the Church. It consults theologians, true, but it then takes an interpretation of a theological opinion (among many) as dogma, or as Fr Kramer puts it on the other thread "definitive magisterial teaching". And if it is such, then it certainly is binding on the Catholic conscience. That is why Sedevacantists tell me to 'return to the Church'. The reply is: when did I leave it? It doesn't seem to have a consistent or logical answer. It is wrong to depose the Pope authoritatively on the basis of a (perceived) theological opinion, whether you argue from the point of heresy, ecclesiology, infallibility, election, it's always the same. As Fr Chazal says in Contra Cekadam regarding the deposition of the heretic Pope: "The practical behaviour of Catholics does not depend in any way on an opinion. What you say as a private person is not a dogma... and before Vatican II no dogma on this intricate, controversial and until then academic question had ever been formulated. On the contrary, with the exception of the time of Gratian, the constant unanimity was that there is no unanimity on this question."

There is no teaching of the Church that a Pope could not attempt such a thing ....

Among the prerogatives conferred on His Church by Christ is the gift of indefectibility. By this term is signified, not merely that the Church will persist to the end of time, but further, that it will preserve unimpaired its essential characteristics. The Church can never undergo any constitutional change which will make it, as a social organism, something different from what it was originally. It can never become corrupt in faith or in morals; nor can it ever lose the Apostolic hierarchy, or the sacraments through which Christ communicates grace to men. The gift of indefectibility is expressly promised to the Church by Christ, in the words in which He declares that the gates of hell shall not prevail against it. It is manifest that, could the storms which the Church encounters so shake it as to alter its essential characteristics and make it other than Christ intended it to be, the gates of hell, i.e. the powers of evil, would have prevailed. It is clear, too, that could the Church suffer substantial change, it would no longer be an instrument capable of accomplishing the work for which God called it in to being. He established it that it might be to all men the school of holiness. This it would cease to be if ever it could set up a false and corrupt moral standard. He established it to proclaim His revelation to the world, and charged it to warn all men that unless they accepted that message they must perish everlastingly. Could the Church, in defining the truths of revelation err in the smallest point, such a charge would be impossible. No body could enforce under such a penalty the acceptance of what might be erroneous. By the hierarchy and the sacraments, Christ, further, made the Church the depositary of the graces of the Passion. Were it to lose either of these, it could no longer dispense to men the treasures of grace.

And your assertion that the Church loses the hierarchy when an Antipope usurps the papacy is absurd, as this has happened many times throughout Church history, nor is the hierarchy lost during any interregnum.