I did some research on the subject in a book I have: Fundamentals of Catholic Dogma by Ludwig Ott. It is available from TAN BOOkS AND PUBLISHERS, Inc., and most likely other sources. (maybe a used copy from
Amazon.com or in in a library somewhere).
If you can get your hands on a copy, go to pages 199-202 and you will find the statement;
“Mary was conceived without sin,” which is followed by “De Fide,”
'De Fide," means this is what the whole of the Catholic Church has come to believe and are required to believe after centuries of study, contemplation, and vigorous discussions leading to an explanation of the dogma, proof from Holy Writ and Tradition, the historical development since the 12th century A. D.
On December 8, 1854, Pope Pius IX, havng consulted the entire episcopate (all the bishops of the Church), and speaking “Ex Cathedra,” (from the Chair) declared the doctrine of the Immaculate Conception to be dogma of the Faith.
A bit of explanation is necessary here. Ex Cathedra, “from the chair of St. Peter,” has a very specific meaning in that all our popes are in a sense are another “Peter” in the same sense as our first pope, Peter who walked with Jesus, was taught by Jesus, and appointed by Jesus as our first pope, (All bishops in the Church are apostles in the same sense as the original 12)
Remember what Jesus said to Peter:
“I give you the keys to the kingdom and he who hears you hears me.”
He also changed peter’s name from Simon to Peter which has always had a very specific meaning similar to God changing Abram to Abraham, etc. This has always had the effect of being appointed to a great task. He only did this for Peter and not the other remaining eleven.
I must add that this is all from my own perspective as a believing Roman Catholic of over 70 years. I have a scientific academic background which means my thinking processes are investigative in nature.
Even so, I must still follow the advice of: St. Augustine, “I believe, in order to understand; and I understand, the better to believe,” and vigorously pursue understanding my faith to better my belief in it.
God bless…
Bussi