I went through the same dilemma a few years ago. It was all about arguments. Who had the best arguments, who had the best science and so on. I’m convinced that line of reasoning is flawed. As a theist, you’re naturally sensitive to non-theist criticism. During my brief period as an agnostic, perhaps surprisingly, I felt sensitive to theist criticism.
Consider these ideas:
Mystery is not inherently wrong. A long tradition in Catholicism is the idea of - get this -
not knowing. Certain things are mysterious, not because we can’t mount an argument for them, but because they are
supposed to be mysterious. (Which of course is no surprise to a churchgoer - “let us proclaim the
mystery of faith” and so on).) Throughout it’s history, the church has rationally been at peace with this idea.
One thing I’ve always disliked about Eastern Christianity was its obsession with mystery. Not that I disdain the concept of mystery in any way. If Christianity is true, then mystery is a neccessary component. However, far too often it seems as though theists like to classify outright contradictions, logical inconsistencies as “mysteries”. This satisfies no one, and while it may bring comfort to someone who is unwilling to thoroughly assess what they believe and why they believe it, I could not live with myself knowing that I let emptional weakness triumph over my passion for truth. We only live life once, and I’d like to do it right. I want to become a monk, I really, really do. I want to fall in love with Christ and spend the rest of my fleshy existence contemplating the divine mysteries. However, I don’t want to waste my life on a lie. Not if I can help it, anyway.
(Your first question is actually a question I’ve struggled with. If you want a modern, reasoned, intelligent argument for dualism I’d recommend Richard Swinburne’s The Evolution of the Soul.)
I’ve read Swineburne, and I found it thoroughly unconvincing. On the online secular library, they have quite a few comprehensive, convincing essays that seemingly demolish mind-body dualism. Again, I would still categorically define myself as a Catholic, but, these things, if true, and they sppear to be so, call for a radical redefinition, if not total abandonment of the mind’s existence in relation to the brain.
It’s OK to believe in God based on faith alone. It’s a mature stance to take. Of the internet discussions you’ll find, this is likely the most unvoiced opinion. It feels like
everyone, of every persuasion, feels that God has to be proven, devined, or calculated somehow. It’s a futile effort. At best, you can maybe get a feel for whether God exists, but it depends on the assumption that you
know what God is or does (i.e. creationists know God is adverse to evolution).
Vatican I affirmed, as dogma, I believe, that theism can be arrived at by purely rational, emirical means. If God cannot be approached rationally, as seems to be the case, then the 1st Vatican Council was in error. Undermining the Catholic religion. Far too often, “faith” is code for suppression of the intellect.
It’s freeing to move past all of that guessing. Go by what feels intuitive to you. It’s more rewarding, and your faith will be built on a much more solid foundation. Trying to build faith on the hottest argument around doesn’t work when you read a convincing counterargument. Just try letting it all go. It may put you at ease.
Intuition? I don’t think any of the Church Fathers would have advocated approaching the things of faith with intuition! If so, what of the homosexuals and the modernists! Their intuitions place them in direct opposition to the teachings of the Church. As for being at peace, I’m not looking for it. I want the truth.
I’d recommend you check out Fr. Robert Barron’s youtube channel and articles. Start with
this article - it addresses a lot of the common criticisms of faith that you find online. Fr. Barron is very sharp, it’s definitely worth the look.