Nihilism?
Merriam Webster's dictionary defines beleif as "a degree of conviction of the truth of something esp. based on a consideration or examination of the evidence". I find, when speaking with people on a personal level, there apears to be a significant level of disparity between Merriam Webster's conception of the word and the average american's. The disparity being "examination of the evidence". The definition I liked slightly better was the 1st listed by dictionary.com, "The mental act, condition, or habit of placing trust or confidence in another". I liked this one more becuase it doesn't state that any kind of trust / conviction is rational or logically motivated. The definiton I liked the very best was from wordnet, "a vague idea in which some confidence is placed". I liked this one especially, since it's almost the complete opposite of Merriam Webster's.
I also looked up belief in a thesaurus and found that many of it's listed synonyms were also somewhat in conflict. The two that stuck out most were "hypothesis" and "conclusion". Both of these terms, according to Mr. Roget, are potentially synonomous with the the word "belief". From an Imperical, scientific, perspective a hypothesis is a notion based on speculation, or edjucated geusswork. A conclusion is the proven / dis-proven notion you're left with after testing your hypothesis via trail and error. I't seems that the word belief can describe any a persons level of trust in any idea but, but with certainty of the idea at an undefined level.

It's been my observation that when people have a feeling of 100 onviction based on un-disputed evidence, they usually use the word know. Know is the prefix of the word knowledge, and can be used in sentences like, "I know this for a fact.", or, "I know that you idjit." It's usualy when people are aware that others posses viable dispute over their evidence that they use the word belief. I've often used the word myself to avoid debating topics that could potentially lead to beligernce. Maybe I don't know for a fact that OJ did it, but I believe he did.

Personally, I believe in nothing, not even my own existence. Although it's obvious that I am here, you need to define three things. I, am, and here. The problem with language is multi-level redundancy. First you have reality, suposedly. Then you have thoughts, apparently your mind's analysis of reality, then you have words, lingual systems of decriptors assigned to each little byte of mental analysis. The problem with human communication is that different people posess highly variable degrees of percision when it comes to mental analysis, un-precise allocation of knowledge leads to poor communication through mis-assigned thoughts, and the misperception of a mind's conception of another person's words.

I = ?, am=?, here=?. There are potentially thousands of possible descriptors that can be used to fill in these ?s, all depending on my location and personal attributes, at the time the statement is made. Most of which will be relativelly well received, given they are truthful from a reality bound perspective. The problem with a concept like belief is that is deals with an x level of certainty. If I tell you, I'm at the mall, and I'm really not, I've led you to beleive I'm at the mall, eventhough I'm not . If someone asked you where I am you might say, "I believe he's at the mall", or, "he told me he's at the mall", actually you'd probably just say, "he's at the mall". It doesn't really matter, whats impotant is that your beleif, although a totally adequate means of reasoning in this instance is completely limiting your perspective. My location could be a vast number places limited by time, distance, and my ability to travel.

Although, "where I am?" might not be of great enough consequence to justify a super high degree of deductive reasoning. I'm sure there are questions in life that are. Most people it seems, "beleive" there are answers to those questions, some even "believe" with 100 onviction that they already posess those answers. But let me just say it's because of concepts like belief that true satisfaction and clearer understanding of existence will never be obtained.