From time to time I get enquiries about the validity of the Orders of the post-Conciliar Church. I've tended to ignore such questions until now, because "the post-Vatican II Church" is the One, Holy Catholic Apostolic Church of God, just as much as "the Post-Tridentine Church" was, in full continuity with the Church of all ages. I have no intention of even seeming to accept the possibility of a 'sedevacantist' analysis being worth taking seriously. But, well, if there are people who are worried by this question and really want help ... you did ask ...
The preliminary logical question to be put to those who find themselves tempted by Sedevacantism is: "You claim to hold the basic Catholic dogmas that the Church is indefectible; and that the Bishop of Rome holds a unique and God-given place within the life of that Church. How many more decades does the Roman See have to be vacant before these combined doctrines become impossible for sedevacantists to hold?" It seems to me significant that, at this moment, Bishop Williamson is very painstakingly putting lots of blue water between himself and Sedevacantism. He wasn't born yesterday. There are no flies on him. He is a Wykehamist. He doesn't want to get caught in that little trap.
And if the post-Vatican II Church is the Catholic Church, and is indefectible, you can't argue that the overwhelming majority of its bishops and priests are not bishops and priests in the sight of God. Or, if you can do it, you'll have to write a very long and very clever book to do so.
However, prescinding from those rather obvious ... I would say, totally conclusive ... points ... I come now to the substance of the arguments that Ordinations according to the post-Conciliar Pontifical are not valid.
It is suggested that the 'form' used in the post-Vatican II rites for the consecration of a Bishop (which is what I am going to concentrate upon) is insufficiently precise. But any language, and any specialised subform of any language, has its own internal logic. If the Church, in the new rites, in effect says "We decree that the words spiritus principalis hereafter and herein are to have the meaning of episkope", then that is the meaning they do have, even if they didn't have it beforehand. Just as legislatures enacting legislation, or solicitors composing legal agreements, all commonly begin by defining terms ("within this Act/Agreement, the term The Society shall be deemed to mean the United Society of Water Diviners and Weak Beer Drinkers of the Parish of Little Snottingham in the Parliamentary Constituency of West Barsetshire"). Such assignment of precision to a potentially vague term is effective for the described purpose.
To be continued for two more sections. I sha'n't enable comments till I've finished.