In other words, here and now, is it possible for me to have authentic, rational, and saving faith even if I have not convinced myself of the preambula fidei yet? Or must my faith be fideistic if I am to have faith at all here and now?
Hi PM,
I decided to use this formulation of your question since it makes the most sense to me. Before I can give an answer though, I want to look at what the Church teaches about the relationship between reason and faith.
A good place to start is the encyclical from Pope JPII
FIDES ET RATIO. In some ways it is a difficult read, but I’m not asking that you analyze the entire encyclical, unless you wish. I just want to bring up a couple of points that I think are helpful.
First, the term “faith” is normally used in this context as trust in another
person to convey the truth reliably. “Reason” is the independent act of the human mind to determine truth. In his comment on
Fides Et Ratio, Alvin Plantinga puts it this way:
The pope doesn’t say so here, but the Thomistic reason for observing this distinction is that (so the thought goes) to know or believe something by way of
faith is to know or believe it on the basis of someone else’s say-so, testimony; but what you learn for yourself, by way of reason, is something you “know better,” something that has more epistemic clout, a higher kind of epistemic status, for you than what you believe on the authority of someone else (even God). For example, if I believe the Fundamental Theorem of Calculus on the authority of my mathematician friend Paul, I don’t know it as well as if I learn the appropriate bit of mathematics and come myself to see how the proof goes. (But isn’t this doubtful? Given my mathematical limitations and my dubious grasp of the proof, perhaps I’d be better off believing on Paul’s authority.") [Plantinga](file:///C:/Users/todg.CMD-LAW/Desktop/a_response_to_pope_john_paul_IIs_fides_et_ratio.doc.htm)
While I don’t agree with everything Plantinga says in this article, his illustration is a good one of how often our faith in other people and their conclusions exceed our confidence in our own reasoning. Everybody does this, regardless of whether that faith is in God or in the institutional Church. When we find a person to be trustworthy and knowledgeable about what he reveals to us, we usually continue to rely upon that person; even to the point where we claim we “know” things based upon the testimony of that person. This is also why we can claim a rational faith.
Second, according to
FIDES ET RATIO, faith and reason can never contradict each other. In fact, they supplement and support one another. In Plantinga’s example, if I do independently apprehend and understand the details of the mathematical theorem, I will have even more faith in my friend Paul. On the other hand, that my friend Paul gave me the correct conclusion assisted me in finding the way to use my own reasoning to come to the conclusion myself. It is where it appears to me (you) that reason contradicts faith in God and the Church that we must make a choice; whether it be a dilemma concerning the existence of God, the Incarnation of Christ, or the authority of the Catholic Church. We have few choices in this situation: my reasoning must be wrong, my faith must be wrong, or both my reasoning and faith must be wrong. With that being said, I will try to address your question.
I don’t think you must become a
fideist simply because you are experiencing doubts about the
preambula fidei. I think this would only be true if you asserted your faith claims in positive contradiction to reason. As others here have suggested, if it is only a doubt (likely a specific one) of whether your reason comports with faith then I don’t see how you are deprived of rational and saving faith. I think that can only happen when you make a judgment that your reason in some particular is superior and in opposition to faith in God and the Church.
. Effectively, to suspend faith in the Catholic Church to look for alternative or even proof is to give your faith to something else 
This means you cannot avoid holding something without proof, so why not have it in Christ and the Church?