I was just reading from your church website on what is wrong with the teachings of Catholicism, and I had a question regarding this particular quote:
"As I mentioned before, the departure of the Catholic Church from the teachings in the Bible leaves a large number of differences. Apologists for Catholicism do not attempt explain away those differences. Instead, they will argue for the right of the Catholic Church to modify the doctrine of Christ to suit their purpose. It does not matter to them that they are not practicing the religion found in the Scriptures because they believe they have evolved Christianity into a new and better religion."
Have you been to "www.catholic.com"? It's written and run by an impressive amount of Catholic apologists who address every single issue you've brought up, and more. They do not "argue for the right" to change doctrine to suit their agendas of being right - they always go back to the Bible and it's original meaning, in context, then expand on that using what they call "Sacred Tradition", which has been garnered from the original teachings of the apostles and their disciples, commonly called the Early Church Fathers.
And in regards to your list of how the Catholic church has changed its doctrine repeatedly (by which I assume you mean through the various councils), please remember that "...any council's purpose is to re-explore and reaffirm the original teaching of Christ that is presently being questioned." ~ David Currie, "Born Fundamentalist, Born-Again Catholic"
It appears that someone wishes to advertise the Roman Catholic church's web site, since this the second note in just a few days asking if I had seen it. Just for fun, I will quote from one of its articles to prove my point:
Catholics, on the other hand, hold that there may be, that there is in fact, and that there must of necessity be certain revealed truths apart from those contained in the Bible; they hold furthermore that Jesus Christ has established in fact, and that to adapt the means to the end He should have established, a living organ as much to transmit Scripture and written Revelation as to place revealed truth within reach of everyone always and everywhere." [Tradition and Living Magisterium, Catholic.com].
Since the claim is that all truth is not in the Bible, it is false to state that they prove their points by starting with the Scriptures. A quick check of a few answers shows that many contain no Scriptural references or admittance that the topic under consideration is not found in the Bible.
Let me direct your attention to the words "adapt" and "living organ." This is simply a claim that the Roman Catholic church believes it as the right to modify and grow teachings to suit circumstances. One means used for evolving ideas is to realize that controversial topics have been argued for centuries. Thus if there is some position you would like to take, it is not too difficult to find someone somewhere who supported the idea.
"When the Church studies the ancient monuments of her faith she casts over the past the reflection of her living and present thought and by some sympathy of the truth of today with that of yesterday she succeeds in recognizing through the obscurities and inaccuracies of ancient formulas the portions of traditional truth, even when they are mixed with error." [Tradition and Living Magisterium, Catholic.com].
Notice that these ancient controversies are interpreted in regard to present thought. Thus a stance that is currently desired can be supported by the past. But the determining factor of what is accepted is what the Catholic church wants as a whole.
"The living magisterium, therefore, makes extensive use of documents of the past, but it does so while judging and interpreting, gladly finding in them its present thought, but likewise, when needful, distinguishing its present thought from what is traditional only in appearance. ... Thus are explained both her respect for the writings of the Fathers of the Church and her supreme independence towards those writings; she judges them more than she is judged by them." [Tradition and Living Magisterium, Catholic.com].
"Closer study of the living magisterium will enable us to better understand the splendid organism created by God and gradually developed that it might preserve, transmit, and bring within the reach of all revealed truth, ever the same, but adapted to every variety of time, circumstances, and environment." [Tradition and Living Magisterium, Catholic.com].
The document Tradition and Living Magisterium states near the end that this is how the concept of Mary being sinless developed. It readily notes that when the idea was first introduced, it was resisted, but has it took hold in the members of the Catholic church, they found justification for what people wanted to believe in their documents. Thus they can claim that a new idea wasn't all that new after all. "In recognizing a new truth the Church thereby recognizes that it already possessed that truth." [Tradition and Living Magisterium, Catholic.com]. But for my purpose, it is also an admittance that the belief that Mary was sinless was not accepted for a long while -- not until pressure built up to find justification for the idea. Thus the Roman Catholic church evolves over time. Details from Roman Catholic documents of this change in teachings can be found in "Why did Catholicism start and when did it happen?"
"Holy Scripture is therefore not the only theological source of the Revelation made by God to His Church. Side by side with Scripture there is tradition, side by side with the written revelation there is the oral revelation." [Tradition and Living Magisterium, Catholic.com].
It is in the third category, a belief in continued revelations, that the Catholic church finds solace in introducing new teachings. That is why documentation of the changes which Catholicism has taken, such as listed in "What is wrong with Catholicism?" upsets some Catholics. Even if past documents do not yield support for an idea, there can always be a claim of a new revelation.
When I say that Catholic apologists always go back to the Bible, I mean exactly that, in a more basic sense than the one you presented: I mean that, through the Bible, there is no evidence that every truth is found in the Bible. Catholic.com does an excellent job defending that statement.
That the doctrines have matured over the centuries is not offensive to me in any way, because Christ gave the Holy Spirit to the Church, to guide her and lead her to the truth. Now that can be found in the Bible, in, among others, John 16:12-13.
And I wouldn't say that there can be a claim to new revelation in a sense that Catholics can make up whatever they want if it fits their agenda. I'd say that we will never be able to fully comprehend and understand the greatness of God; therefore, there are always new things to learn, and, as long as they don't contradict Sacred Scripture and Sacred Tradition, I'm not one to say that it doesn't happen.
Thank you for confirming my points. While you are comfortable with the idea that you don't have the truth -- only a claim to have a portion of it, with the remainder yet to be found, I am persuaded otherwise.
For example, you stated, "There is no evidence that every truth is found in the Bible."
"Sanctify them by Your truth. Your word is truth" (John 17:17).
"And that from childhood you have known the Holy Scriptures, which are able to make you wise for salvation through faith which is in Christ Jesus. All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness, that the man of God may be complete, thoroughly equipped for every good work" (II Timothy 3:15-17).
"As His divine power has given to us all things that pertain to life and godliness, through the knowledge of Him who called us by glory and virtue" (II Peter 1:3).
"Beloved, while I was very diligent to write to you concerning our common salvation, I found it necessary to write to you exhorting you to contend earnestly for the faith which was once for all delivered to the saints" (Jude 3).
"I marvel that you are turning away so soon from Him who called you in the grace of Christ, to a different gospel, which is not another; but there are some who trouble you and want to pervert the gospel of Christ. But even if we, or an angel from heaven, preach any other gospel to you than what we have preached to you, let him be accursed. As we have said before, so now I say again, if anyone preaches any other gospel to you than what you have received, let him be accursed. For do I now persuade men, or God? Or do I seek to please men? For if I still pleased men, I would not be a bondservant of Christ" (Galatians 1:6-10).
You also took a statement that Jesus made to his apostles and applied it to the Catholic church. "I still have many things to say to you, but you cannot bear them now. However, when He, the Spirit of truth, has come, He will guide you into all truth; for He will not speak on His own authority, but whatever He hears He will speak; and He will tell you things to come" (John 16:12-13). What Jesus promised the apostles was fulfilled. He promised them inspiration and they received it so they might pass the truth on to those who followed. "That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon, and our hands have handled, concerning the Word of life -- the life was manifested, and we have seen, and bear witness, and declare to you that eternal life which was with the Father and was manifested to us -- that which we have seen and heard we declare to you, that you also may have fellowship with us; and truly our fellowship is with the Father and with His Son Jesus Christ. And these things we write to you that your joy may be full" (I John 1:1-4). They were able to relay this message accurately, even the things they did not understand when Jesus was here on earth, because the Holy Spirit was guiding them. "But God has revealed them to us through His Spirit. For the Spirit searches all things, yes, the deep things of God. For what man knows the things of a man except the spirit of the man which is in him? Even so no one knows the things of God except the Spirit of God. Now we have received, not the spirit of the world, but the Spirit who is from God, that we might know the things that have been freely given to us by God. These things we also speak, not in words which man's wisdom teaches but which the Holy Spirit teaches, comparing spiritual things with spiritual" (I Corinthians 2:10-13).
The apostles accomplished their given mission. They established the church and left it the teachings of Christ to guide Christians through the rest of the ages.
In regards to a willingness to learn new things, I'll direct your attention to the article, "Learning from the Vatican's Reversal on Galileo."