In his 1926 essay, Why I Am a Catholic, Chesterton would tell us.
The difficulty of explaining “why I am a Catholic” is that there are ten thousand reasons all amounting to one reason: that Catholicism is true. I could fill all my space with separate sentences each beginning with the words, “It is the only thing that …” As, for instance, (1) It is the only thing that really prevents a sin from being a secret. (2) It is the only thing in which the superior cannot be superior, in the sense of supercilious. (3) It is the only thing that frees a man from the degrading slavery of being a child of his age. (4) It is the only thing that talks as if it were the truth; as if it were a real messenger refusing to tamper with a real message …
The Church does often set herself against the fashion of this world that passes away; and she has experience enough to know how very rapidly it does pass away …
Nine out of ten of what we call new ideas are simply old mistakes. The Catholic Church has for one of her chief duties that of preventing people from making those old mistakes; from making them over and over again forever, as people always do if they are left to themselves
There is no other case of one continuous intelligent institution that has been thinking about thinking for two thousand years. Its experience naturally covers nearly all experiences; and especially nearly all errors. The result is a map in which all the blind alleys and bad roads are clearly marked, all the ways that have been shown to be worthless by the best of all evidence: the evidence of those who have gone down them. …
But [the Church] does definitely take the responsibility of marking certain roads as leading nowhere or leading to destruction, to a blank wall, or a sheer precipice. By this means, it does prevent men from wasting their time or losing their lives upon paths that have been found futile or disastrous again and again in the past, but which might otherwise entrap travelers again and again in the future. The Church does make herself responsible for warning her people against these; and upon these the real issue of the case depends. She does dogmatically defend humanity from its worst foes, those hoary and horrible and devouring monsters of the old mistakes …Now there is no other corporate mind in the world that is thus on the watch to prevent minds from going wrong. The policeman comes too late when he tries to prevent men from going wrong. The doctor comes too late, for he only comes to lock up a madman, not to advise a sane man on how not to go mad …Every moment increases for us the moral necessity for such an immortal mind. We must have something that will hold the four corners of the world still …
To read Why I Am a Catholic in full, please visit this link to the American Chesterton Society.