Properly speaking, almost no one reading this believes that I had oatmeal for breakfast this morning.
I know the first statement is true. I am of the opinion the second statement is true -- at least if Josef Pieper is right about what belief is, properly speaking.
[Having been bullied by Kevin Miller into seeking out Pieper's Faith, Hope, Charity, and tricked by Steven Riddle into meeting him in a Catholic bookstore that carried that book, I have now read the first section (it's about "faith") and will proceed to disgorge on this blog such aspects of its contents as have made their way into me. Oh, and don't miss Athanasius's coincident magnum opus on the same topic.]
In Pieper's view, "belief" or "faith" (Glaube, in Pieper's original German) is a little more than "sharing in the knowledge of another." For one thing, it implies certainty. If you truly believe me when I say I had oatmeal for breakfast, then you are as certain about what I had for breakfast as you are about what you had. I'd guess some reading this do not have that level of certainty regarding what I had for breakfast, and so don't really believe me. (Perhaps instead they "accept for practical purposes" that I had oatmeal, which is easy to do since there aren't any practical purposes.)
Furthermore, the primary meaning of belief refers to a person, not a thing. You believe me; the intellectual content of the knowledge I share with you is a secondary thing. Usages like, "I believe I just saw a yellow-bellied sapsucker," are, for Pieper, "improper," meaning they don't reflect any unique meaning of "believe." His method for identifying improper usage is to see whether another word could be used in its place; e.g., "I think I just saw a yellow-bellied sapsucker." Properly speaking, you can't believe you saw something, because there's no other whose knowledge you're sharing.
The last, and strictest, pf Pieper's conditions for belief is that the certainty with which one believes must rest entirely in the person whose knowledge is shared. If, after reading my statement about having oatmeal for breakfast, you considered the reasonableness of someone like me eating something like oatmeal for something like breakfast, perhaps also folding in the time of year and the weather in my part of the world and the lack of apparent benefit to myself of lying about it, and concluded that, apart from any trustworthiness you might assign to me, it could well be true that I had oatmeal for breakfast this morning, then you don't really believe me so much as accept what I've said as conditionally true.
The thing about this last condition is that it makes it all but impossible for one person to believe another person. Your belief is a sharing in my knowledge, not an admixture of common knowledge with an added dash of something I said that affects various odds.
In fact, Pieper goes as far as to suggest there's something inhuman about believing another human in the proper sense. If I told you I had unicorn for breakfast, and you believed me, there would be nothing praiseworthy in that belief.
I think there's something to be said about believing (in the proper sense) someone you love, but I'd agree the vast majority of human relationships do not call for such belief.
Okay, so all this is according to Pieper. Who says Pieper is the authority on what belief means? Heck, he wrote in a language that uses the same word for "belief" and "faith."
The real question, though, isn't about dictionary definitions, but whether the concept Pieper has described has any relevance, in particular relevance to man as a religious being. I think the answer is clearly yes. His concept of belief --which, when attached to another human, is inhuman -- becomes, when attached to God, necessary for the fulfillment of our humanity.