(My previous comments didn't appear, it seems)

Basically: What is missing in the above text is the notion of "openness": most people are not open. If not christians, they consider God as "impossible" (outside the boundaries of what the reason may accept).

Felixcox, is the choice really between being "comfortable remaining gullible" and hyper-skepticism? Might there be a middle ground?

If somebody I trust says X is true, I'm likely to believe X, even if X is an invisible entity. For example, I believe the scientists and textbooks testifying such invisible entities as black holes exist. I've not worked through the evidence to transform that belief in to knowledge proper, and why should I? I've no reason to distrust the scientists.

Likewise, I've no reason to distrust the testimony of credible competent sources about such incorporeal persons as God and the angels.

As for your example of "garden fairies" and "invisible dwarfs guarding the pot of gold" nobody I trust has claimed they exist.

Actually both justifications you proposed for cannibalism are based on reason. If god exists and you have good evidence that he told you you should eat people, it is reasonable to do so.

Depending on what you mean by prove I don't think one needs to prove things to believe them. you do need a reasonable basis though, but once you have this, there is no need for faith.

If you don't have a reasonable basis to say God told you to eat people, I don't care how much faith you have, I won't let you do it, because I have good reasons to stop you that have nothing to do with subjective faith.

For Catholics (and I would invite my Internet friends to pay very close attention here), authentic faith never involves a sacrificium intellectus (a "sacrifice of the
intellect").

Unfortunately, this claim is demonstrably false. Please note the word “never’. This is a very specific word that means not ever. When Savita Halappanavar died in Ireland because she could not get an abortion of a pregnancy that was killing her, she was told as she died the reason (i.e., “because this is a Catholic country”) that she would not receive the treatment intellectually known to be best. When Bishop Thomas J. Olmstead excommunicated Sister Margaret Mary McBride because she allowed an abortion to save the life of the mother versus allowing the death of both mother and unborn child, Catholic faith was used to supersede the best intellectual knowledge of proper medical practice.

If your claim had replaced the word “never” with something like “almost never” then the claim might change from being false to being true. But as it is written, it is false. My problem is not so much with whether the claim is true or false, my problem is with the profound lack of self knowledge reflected in your believing something about yourself that is demonstrably false.

Brain,
Yes, you can (and should) question anything.
We all believe things we can’t prove. We all have a worldview. Using reason alone I can justify cannibalism as a good evolutionary strategy to eliminate a competing tribe and obtain a good source of protein at the same time. Using faith alone, can say cannibalism is good just because I believe it is and God told me so. Reality is a combination of physical laws and spiritual laws. We need more than only calculating logic to understand the reality of cannibalism or any other worldview. Reason alone is never enough.

"Whatever the case may be, societies primarily comprised of atheists are doing just fine in northern europe."

Define "doing just fine".

I know you are saying this, but I have no idea why. If I have a car and the fuel light comes on, reason tells me to refuel. How does faith help this decision or any other? I can't think of any circumstance where reason cant get it right without faith. but i can think of many where faith works against the best result. If i have faith that my car is so great that it can make it another 30 miles where the gas is cheaper and I run out of gas. I have faith that my prayers have cured my child of diabetes. I have faith that I am called to jihad, to a crusade. Such people can and do explain their actions as reasonable interpretation of scripture when done in faith. I can use reason to challenge these actions, but I can't question their faith.