We have addressed some fundamental truths about God, as the Catholic Church teaches them. We have shown why we can trust the Church in theory. But with so many Church controversies throughout history, can we truly trust her?
Before we address individual Church teachings, we must understand how the Church acts. The Church does not make anything up. Rather, guided by the Holy Spirit, she interprets the truth in light of Divine Revelation. Catholics often refer to the principle of the Development of Doctrine – a theory which has a long pedigree. St. Vincent of Lerins was the first person to formally present the theory, in 434 A.D. St. John Henry Newman revived widespread interest in the theory in the 19th century.
By using the word “development,” this principle does not mean that doctrine changes. If that were the case, we should not trust the Church because she would not be teaching the truth, for the truth does not change. But this development rather refers to the Church’s understanding of truth. The Church’s understanding of truth has grown over time. For example, the Church did not define the dogma of the Assumption until 1950. The majority of the Catholic faithful believed this doctrine for centuries before it was made a dogma, and its roots go back to the early Church. In other words, the Church did not assume that the Blessed Virgin Mary was assumed into Heaven at the consummation of her earthly life, but utilized Sacred Scripture and Sacred Tradition to understand it. So, truth exists outside the Church, and God guides the Church to slowly unearth it.
Now, one might question why God would not reveal every truth to the Church at once, instead of making us try to figure out the truth and potentially err in the process. God allows us to figure out the truth, guided by His grace, because He wants us to grow in charity. If He revealed everything to us at once, then we would have less of a stake in His Mercy. St. Francis de Sales says that “we can only love by practicing love.” In a similar way, we can better appreciate the truth if it costs us something to attain it. The working man who receives a paycheck of $50 for a hard day’s work will probably be more satisfied than one who is given $50 for doing nothing. If we work for God, we become more disposed to Him in the process, and thus grow in love of Him and our neighbor for His sake. Consequently, it makes sense that the Lord would intend for the Church, like mankind, to come to the truth in steps.
But the Church also, even if sure of a certain truth, waits to defend it until it is attacked. It is usually superfluous to defend something that is not being attacked. “The profession and the developments of a doctrine are according to the emergency of the time, and silence at a certain period implies, not that it was not then held, but that it was not questioned” (An Essay on the Development of Christian Doctrine 370). Doctrine develops, but it does not change.
So now that we know that the Church uses the Deposit of Faith, which consists of both Sacred Scripture and Sacred Tradition, in order to interpret Divine Revelation, we can examine one of the most fundamental truths of the Catholic Faith, a truth which most Christians would agree with – the Most Holy Trinity.