> As to why the specific teachings of the Catholic church? It literally comes down to "God said so and God wouldn't lie."
How do you know god said so? How do you know there even is a god? How do you know god wouldn't lie?
You assumed it (in one way or another). Blind faith.
BTW, regarding the whole "god doesn't lie" thing:
> O LORD, thou hast deceived me, and I was deceived: thou art stronger than I, and hast prevailed: I am in derision daily, every one mocketh me.
Jeremiah 20:7
> And if the prophet be deceived when he hath spoken a thing, I the LORD have deceived that prophet, and I will stretch out my hand upon him, and will destroy him from the midst of my people Israel.
Ezekiel 14:9
> And for this cause God shall send them strong delusion, that they should believe a lie:
2 Thessalonians 2:11
But Bible is full of contradictions, it's not like anybody can be persuaded by pointing them out. Faith doesn't care about contradictions :)
> these have to do with a variety of purely rational, if not always convincing arguments.
Arguments using circular reasoning are indeed not very convincing :)
> that God, the first cause (principium) and last end of all things, can, from created things, be known with certainty by the natural light of human reason
There's no way to deduce anything about the first cause. Not the fact that it would also necessarily be the end of all things. Not that it was something conscious with a free will. Much less again that it was a personal god. Much less still that it was the God as Catholics define him.
And it's perfectly possible that there was no first cause at all (the chain of causes could be infinite for all we know).
> Catholics believe that the existence of God can be proved with reason.
And that's blind faith, because they can't actually prove it, they just declare it's possible. You're arguing my point for me here ;)