I am recounting in chronological order the several reasons I have for accepting that the Catholic Church is what she says she is.
The second is the paradox of accepting on authority the doctrines of the Incarnation and the Trinity but rejecting authority defining those doctrines.
I did not back when I was an atheist (and do not now that I am a faithful Christian) see how anyone can reject the Church without rejecting the writings of the Church. If the Church is not sacred, how can her writings be sacred? And if her writings are sacred, how can the Church not also be?
There are only two possible answers: one is to say that the Church had her authority, legitimately exercised, up through the period where the New Testament writings were written, collected, and canonized, and lost that authority thereafter. The answer depends for its probative value on the date assigned as the point of last legitimate authority, after which the Church’s apostasy was irrevocable. Any doctrines promoted before that date are presumptively valid, as being given by a legitimate authority.
The other answer is to say that the Church never possessed magisterial authority, that is, the authority to define Christian teaching, and that this power lodges either in the individual, or nowhere.
The logical fallacy involved in this second answer is obvious: if the Church never possessed the authority to define doctrine, then nothing in the Christian canon, not even the fact that Christ existed at all, has any authoritative support.
It is not as if there are independent non-Christian written records testifying to the events in the Gospel or the visions of St Paul or St John aside from the apostles and disciples themselves. Aside from the testimony of Peter and Paul and the other saints and apostles and martyrs, there is no record that Jesus of Nazareth lived at all, much less that He was the Christ, much less that He was divine, and said the things He said.
There is nothing in the Bible listing the canon of scripture. There is not even a rule or standard mentioned explaining how to compile such a list, or to establish what books belong and what do not.
But let us suppose for the sake of argument that there were a book in the Bible, let us call it The Book of Solascripture, which clearly and plainly set out that scripture and not tradition is the sole authority for determining canonicity, that is, giving the standard of what constitutes orthodox teaching. Let us further suppose that the Book of Solascripture lists all books which are orthodox and authoritative, from the Book of Genesis through to the Apocalypse of John. Does the Book of Solascripture list itself in the list? Either it does or it does not.
If it does not, that is a self-contradiction, for then the book by whose authority we know which books are authoritative lacks the authority to make that determination.
If it does, that is a circular argument, for then the book by whose authority we know which books are authoritative is the only witness to support its own authority. It would be like a judge in a court of law declaring himself king on the grounds that, as king, he has the authority to grant this one judge, himself, the right to declare who should be king.
Let us suppose again that the Book of Solascripture was written anywhere from 30 years to 120 after the Crucifixion, as late as 150 A.D. Consider the apostle, let us call him Protoluther, who penned the Epistle of Solascripture. Was everything he taught before that date invalid? Was everything every apostle taught before that date invalid? To them, scripture meant only the Old Testament.
What was his basis for Protoluther’s authority to write this scripture and teach this doctrine that authority comes from scripture alone? That authority must be based on something Christ or one of the other apostles taught to him orally. But if so, by it own definition of authority, this doctrine has no authority to be taught, nor to enter the canon of scripture.
If Protoluther has no authority to proclaim Sola Scritpura as authentic Church teaching, how much less has Luther over a thousand years after. And by what authority does Luther decree that all canonizations from the past thousand years were invalid? How does he get the right to strip the sainthood not from one nor two, but from all the saints back to Saint Mary?
But in fact there is no Book of Solascripture, and in fact there is no passage in the Bible supporting Sola Scriptura. (There is a passage saying scripture is useful for instruction and reproof, however, but this is hardly that same thing). There are also passages indicating that the early Church Fathers spread tradition orally, and relied on oral tradition, and expected it to be spread orally, from one generation to the next.
There is no passage in the Bible indicating that this reliance on tradition was, or was meant to be, temporary or limited to a certain early period. (It may be so that Christ intended or command such a limitation, and that we as Christian should obey His intent or command for the sake of salvation, but, if so, the doctrine of Sola Scriptura is false, for then there is at least one commandment or divine intention, necessary for salvation, which is not in the scripture.)
So, logically, the answer that the Church never possessed teaching authority must be rejected by any Christian. No man determines the nature and content of the Christian teaching for himself on his own authority, because no man living is an eyewitness to Christ.
That leaves the other answer: that the Church at one time possessed teaching authority and lost it on the grounds of her apostasy. This rests on the question of teaching authority. This is turn rests on the question of whether the Church is or is not one, true, holy, catholic, and apostolic.
Hence to support this answer logically, the Protestants have to make four claims: first, that the early Christians in doctrine and practice and to all practical effect were Protestant and not Catholic, on the grounds that the Church suffered an apostasy, slowly or suddenly, at some specific date between the First Century and the Sixteenth; and, second, that this apostasy was final and irrevocable, such that the Church could never reform, repent, nor regain her lost authority; and third that this apostasy grants each Protestant individual the legal authority to rebel in order to return to the original forms of the Church.
Note that this third claim logically gives each individual baptized Christian an authority no Pope nor General Church Council ever claimed, which is the ability to overrule or ignore the findings of any or all previous Church Councils.
This third claim has no support whatever in the constitution of the Church, nor in canon law, nor in the writings of any Church Father, nor in Scripture, nor any basis in logic. Nothing Christ says said that each man can invent his own Church to suit himself.
The fourth and final claim is that each man has the right and authority to interpret scripture for himself. If a ten o’clock scholar reads a passage where, for example, Jesus says none is good but God alone, and he interprets that to mean that Christ was a human prophet and not the Second Person of the Trilogy, his reading is as authoritative as if Saint Peter had said it.
For that matter, if the same scholar decides that the resurrection scenes are meant to be allegorical or poetical, and that Christ never rose from the dead, or never existed to begin with, that is spoken with Peter’s authority also.
Or if he decides that Christ declaring the Eucharist to be His body is allegorical, then Peter’s authority can dismiss the Lord’s Supper as something Christians need not keep; or if he decides that baptism is a spiritual act which is marred or blockaded by the performance of a sacrament using material water, then Peter’s authority teaches Christians must not perform baptisms; or if he decides the serpent in the garden of Eden was the true God seeking to grant men knowledge and divinity whereas the creator was an evil demiurge and the enslaver of man; then by this logic these are all valid readings, all equally Christian, all equally authoritative.