Catholicism... From first principles


Hi everyone,

I hope you all had a very happy Easter.

I’m sure this question has been answered on this forum before somewhere, but I can’t find it.

Anyway: I am an almost-entirely-converted Catholic, and was thinking recently: how would I explain my change of belief to someone? Having previously expounded the importance of rational thinking, and of the philosophical inevitability of at least agnosticism if not outright atheism, what reasons do I have to persuade others?

Like many, my change in attitude has come as a result of embracing the Lord and the Church (i.e. not entirely rationally). I have read a lot of philosophy/theology, and I believe that you certainly can’t prove that God doesn’t exist. Yet, how far can you go to suggest that he does? And not simply that he does, but the He does?

It seems that one has to make the following ‘leaps’:

  1. Some sort of supernatural being exists.
  2. He is the Christian God.
  3. He is the God, specifically, of the Roman Catholic Church.

For me, the biggest leap is between 1 and 2. After all, since so many conversions are based on personal experience (the ‘You can’t invalidate what I feel’ argument) - and those conversions happen not just to Christianity, but to all the other different religions - who are we to say the Christianity is the True one?

Christians certainly don’t have a monopoly on [asserted] miracles; nor (as far as I can tell) is there any intellectually honest reason to assume that the Bible is True, yet the Koran (for example) is False.

If Buddhists, Muslims and Jews can experience so-called ‘Divine Revelation’ too, what makes ‘us’ Right and ‘them’ Wrong?

I’m looking forward to reading your suggestions.




Leaving aside the Catholic faith, and assuming for sake of argument that some religion is the true religion, and that all others are not fully true, how then would you expect one to be able to identify the true religion from all others? That seems to be the key question. Perhaps you could simply ask these people that question.


The brilliant philosopher of common sense, G. K. Chesterton may be of help to you. Have you read his Orthodoxy and The Everlasting Man in which he discusses the questions you raised here.


I don’t think their is a one-size-fits-all apologetic for Catholicism. It’s got to be tailored to each individual. The image in my mind is that of the father going out to meet the prodigal son and journey with him back home. We must go out, much like him, and meet them where they are at, with love and joy.

I find that simply sharing why it is you believe is most authentic. If it should also make sense to them, great. If not, prehaps some other Gospel messanger will have an affect.

I believe there are plenty of converging clues which support the believe in a all-powerful supernatural Creator of the universe. From there, I believe it is a matter of other converging clues which make belief in a personal God, one who interacts with his creation in a personal way more convincing than the god of Deism, for instance. Once you establish hat God is personal, not some watchmaker who has abandoned his watch, then you need to ask which of the various testimonies about God throughout history is most convincing, given the evidence.

We all believe based upon three things, what one might call the “evidence” for belief:

  1. Reason
  2. Experience
  3. Testimony of others

Of all the religions, one must evaluate this evidence, these three things to discern whether this religion is more convincing than alternatvie explanations about God, his world, and his will for us.

For me, after studying all the major world religions, by using ‘calculatus eliminatus,’ no other religion comes close in explaining my own experience of the world, congruent with my own reason and the testimony of those of mankind throughout history, most especially those I love and trust the most in my life.


I recommend a study of the major world religions before devling into dialogue with those of different religions.

I have the following multi-volume series which, while several decades old, does a good job of presenting the beliefs of each of the world religions. Each volume is written by an scholar from that religious tradition.

**Great Religions of Modern Man: Buddhism, Catholicism, Protestantism, Hinduism, Islam, Judaism (1962, Volumes 1-6 Complete) **

I also recommend Truth and Tolerance - Christian Belief and World Religions by Joseph Cardinal Ratzinger.

It’s not an easy-reader, but it is an outstanding text in understanding some fundamental differences among religions.

The best way to answer, “Why not Islam?” or “Why not Buddhism” is to simply study what it is these religions teach, and compare their respective beliefs to that which is compelling to you based upon your experience, reason, and the trustworthy testimony of others.


If i may suggest reading what ever you can get your hands on by peter Kreeft. Especially

The philosophy of tolkein
the God who loves you
handbook of christian apologetics
The journey
socrates meets jesus
A refutation of moral relativism (some really great talks here)

An basically pick up anything by chesterton.


I think the most convincing argument is history.

We know that the world has a beginning. That’s a scientific fact. The theory that the universe is oscilating and that there have been any number of universes before now is largely abandoned. This beginning began in an instant, and all things, including time, came into being. This is scientific theory, which validates Catholic metaphysics as perfected by St. Thomas Aquinas.

That being said, only one group of people ever had the idea that the world was created (speaking of culture’s “Creation myths” is a misnomer. They were “formation” myths): that is the Jews (Augustine: proto-Christians).

We know from anthropology the accuracy of the history of the Bible.

We know that Jesus was a real person that existed in history. We know where he lived. He know where he walked. We know where his followers are buried. We know where he was buried. We know where the empty tomb is.

People who are honest about this fact and don’t kid themselves have to come up with alternative theories, namely, that Jesus was a lunatic or liar and his disciples incredibly credulous, or that these uneducated men deceived the whole world (CS Lewis writes somwhere on the absurdity of these positions).

Finally, The Catholic Church can trace itself all the way back to the apostles. It has stood the test of time. It has witnessed the rise and fall of cultures and kings all around the world. It has suffered crises and scandals of its own, yet, some how, the gates of Hell have not prevailed against it.


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