Apologetics, being the rational defense of Catholic teachings and the answering of arguments against them, has always been a central part of Catholicism and the very spirit of Christianity. It is an intrinsic part of spreading the Gospel - God desires to reach people on all levels of our humanity, and reason is one of the most central parts of our mind and the process of belief. Moreover, it is important for keeping the mind of the Church, and oneself, free from error or confusion. But despite the many apologetic works throughout history, from the Church Father and St. Augustine to the scholastics and St. Aquinas, to Pope John Paul II the Great and Pope Benedict XVI, the message of Catholicism is constant, received directly from God as revelation. These central dogmas have never and can never change - they are our constant Tradition. However, Catholic Tradition also encompasses the interpretation of the Magisterium, begun by the Apostles and thenceforth guided to infallibility by the Holy Spirit under the holy seal of the successor of St. Peter, the Pope. This interpretative "branch" of Tradition is constant, just as revelation is - the Spirit guides both. Magisterial interpretation cannot deviate from God's revelation, as both are Truth from the same Source.
Nevertheless, while the Spirit guides Catholic interpretation to infallibility by the Magisterium, under the Pope, it is not always done by the Magisterium initially. Many teachings which the Church has adopted over time have come from people within the Church who contemplated and studied Tradition themselves, discovering new connections between ancient dogmas, answering heresies and thereby finding new perspectives on Tradition, and many other avenues of scholarship. Further, many of these findings were not even scholarly - such as the Catholic mysticism of St. John of the Cross, the "little" ideal of St. Therese of Lisieux, and the very lives and work of saints such as Francis of Assisi, Joan of Arc and Josemaria Escriva. But even though many saints pursued little or no scholarly work, they reaffirmed, exemplified and clarified the central teachings of Tradition just as much as scholarship.
Despite the claims of Modernism, Catholic Tradition cannot change over time - but around the root and bough of the Gospel, many branches and leaves can grow. These offshoots of interpretation do not deviate from the parent Gospel itself, nor the Tradition that has preceded each new branch, just as branches and leaves are mere extensions of the tree and cannot live without it. The myriad interpretations, affirmations and examples of great Catholic men and women throughout history work to make the Gospel a living tree, rather than a dead husk of a single moment in history, or the ethereal, ultimately meaningless humanist morphological agnosticism of Modernism.
For apologists, a field that I very humbly claim to share some familiarity with, it can sometimes seem pointless to continue writing about and propagating the same teachings that Catholic Tradition has always had, especially with two millennia of growth from some of the greatest minds ever. We often feel as if the only worthy apologetics is to reprint the old material, including the Bible itself (the oldest work of Tradition), and simply hand it out to people, answering questions if need be, but refraining from writing our own work, in our own words. Whenever we feel this temptation, we need to remember: we are individuals. Each person is a new soul, with fresh eyes. Even though Tradition is unchanging, God's Truth immutable, just look at the work of Catholics throughout history. What if St. Augustine, St. Aquinas or St. Francis had said, "it has already been done - my work is pointless"? Imagine all that we would not have now. We only have to look at the spiritual starvation of sola scriptura to see the impoverishment of this. No - God desires all to come to Him personally. Every single person has something to contribute. Your work may not be in the future edition of the Catechism; you may not even be a recognized, canonized saint someday. But we cannot strive for greatness - to be first, we must be last. We must make ourselves vulnerable and give all that we are to God and our fellow man. No one is generic in God's eyes.
Most Catholics seem to think that to be a saint, to be holy, means to be uniform, to conform to the ways saints have done it in the past. No - being human is being an individual. Everyone is different, distinct. Yes, we are all similar, and we should learn from others both present and past. But we each have our own unique personality, perspective, ideas, thoughts, experiences, etc. on life and spirituality.
Though we will not truly create, since God is the only Creator of anything truly new, we create new emphasis and perspectives, highlighting certain aspects of Truth and showing it in a new way based on our unique viewpoint. All saints throughout history have done this - even those who lived in complete simplicity were different. And being new does not mean being revolutionary. It simply means giving a new contribution. Evidence of this beyond the saints is the Bible. Each book is a new experience and a new perspective from a different author.
As Christians, we have an advantage: God, the Author of Creation, tells us His meaning. Life becomes an allegory for Him. While in literature this would give no input from the reader, in Christian spirituality, God is always a mystery, always beyond us in His infinity. Thus, there will always be a new way to see His Truth, and we can simultaneously correspond to God's message and contribute our own ideas. Most are too afraid, too shy, or too indifferent to do this.
Since converting to Christianity, around three years ago (prior to my conversion to Catholicism), I have been discussing, debating and writing apologetically, offering theological answers to questions from people of all religious backgrounds and worldviews, both on and offline. I have also continued this practice as a Catholic. It worked to shape my Christianity, as did my experience of debate in my conversion from atheism to Christianity, ultimately leading me to the rational summit of Catholicism.
Apologetics is certainly a sacred science. However, Catholic apologetics and conversion are quite different from Protestant evangelism - it is not a one-time event, where one mentally accepts the reality of Christ's sacrifice and, by retaining that belief over time, is saved by it, giving peace but ultimately being limited to that time, place and event. Conversion is a lifetime, and salvation occurs after death as the result of this lifelong conversion - meaning, converting our souls towards God in the deepest, brightest ways. Apologetics informs and gives witness for Catholic beliefs; but it cannot be done with the expectation of converting the individual who discusses, reads or learns about the apologetic material. Hope is certainly valid, and indeed is the motive of all Christian evangelism and apologetics - but ultimately, it is the individual's decision. Even God does not force conversion, so how can our efforts do so without using immoral means?
Dr. Scott Hahn, in his book Reasons to Believe about apologetics, stated that the most important activity to strengthen one's resolve in apologetic work is frequent attendance of Mass, and prayer - conversion of oneself. Lorenzo Scupoli, a Catholic spiritual writer of the 16th century and author of Spiritual Combat, said that God desires the conversion of your own soul, the increase of love and devotion within oneself, lived by holiness. Indeed, you have more control over your own conversion than that of others.
I believe apologetics is certainly a wonderful and necessary Christian practice. As Pope John Paul II once said, on the wings of reason and faith the mind ascends to God; without both, we are like birds with only one wing, doomed to stare at the earth and constantly long for flight again. Unfortunately, some clip one or both wings and prefer the dry thirst and hunger of the earth, starving without the Eternal Nourishment of Christ. By converting our souls, in combined effort with the Holy Spirit, we make ourselves worthy of the promises of Christ, as the Catholic Hail Holy Queen prayer begs. Reason, however, is not self-sufficient in the human mind - it requires acceptance, which is belief. As St. Thomas Aquinas says (Summa Theologica, First Article): "Although those things which are beyond man's knowledge may not be sought for by man through his reason, nevertheless, once they are revealed by God, they must be accepted by faith. Hence the sacred text continues, 'For many things are shown to thee above the understanding of man.' (Ecclus. 3:25) And in this, the sacred science consists."