From The Opinionated Dictionary of Religion:
Belief. noun. An idea presumed, but not known, to be true; also called mere belief.
Religious intolerance arose with presumptions of certainty: the sureness that my sect possesses certified knowledge means that I cannot endure your sect's evident error.
If it had always been accepted that belief does not rise to the level of knowledge, religious intolerance might not have marred our histories.
Consider this:
Knowledge is an altogether different matter than belief.
Compare the statement 'I believe a goat has horns' with 'I know a goat has horns.'
They are not identical.
The former sentence hints at doubt and experiential distance from goats, while the latter suggests personal ocular or tactile experience of pointy projections atop sheep-related mammals.
A Swiss mountaineer knows goats have horns, while a Manhattan financier only believes they do. (Or is it vice versa?)
We know very little and we believe much. Of all the ideas crowded into our heads in a lifetime, the majority of them are a matter of belief, not knowledge. Mere Belief.
Consider an array of ideas that are mere beliefs for us:
Historical ideas, ideas about matters that predate our birth, are beliefs for us, not knowledge. We believe a man named Shakespeare wrote a play called Hamlet but we don't know that. We believe Charlemagne was crowned in the year 800 but we don't know that. We believe Confucius was an ancient teacher of ethics but we don't know that.
We may assent to all these and believe them, but we have no certain knowledge of them. They're mere beliefs.
Ideas about matters beyond our expertise are beliefs for us, not knowledge. We believe some hieroglyphics refer to an afterlife but we don't know that if we're not experts called Egyptologists. We believe the distance to the sun in summertime is ninety-one million miles (or 155 thousand million football fields or a trillion pillowcases stacked end to end) but we don't know that if we're not astronomy experts.
Again, we may assent to all these and believe them, but we have no certain knowledge of them. They're mere beliefs.
Ideas beyond the confirmation of our drowsy grasp, our sniffing nose, our glimmering tongue, our bent-back ears, our oval eyes, are mere beliefs for us and not knowledge.
We believe a birch tree has soft bark but we don't know that unless we handle the stuff. We believe a Jeffrey pine smells like butterscotch but we don't know that unless we press our nose into its barked crevices and sniff. We believe Seville oranges are very sour but we don't know that unless we lick their insides. We believe a piccolo trumpet creates high notes but we don't know that until we hear the trumpet competently played. We believe a Fennec fox has massive ears but we don't know that until we lay our eyes upon the mammal.
Again, we may assent to all these and believe them, but we have no certain knowledge of them. They're mere beliefs.
There are exceptions to knowing without the aid of our senses: We can attain certain knowledge of mathematical ideas and ideas we have about our current state of mind. I know 4 x 4 is 16 and I know I am thinking of almonds right now. These are certain.
There are also exceptions to acquiring certainty via the senses since the senses can be fooled: What does a straight stick stuck in water look like? What does a desert mirage look like?
If you want to claim an intuitional sixth sense as a way to certified knowledge, you must permit that argument to every claimant:
'In my heart of hearts I know there's a God' is equal to 'In my heart of hearts I know there's no God' and equal to 'In my heart of hearts I know there's a pink teapot orbiting Mercury.'
There's no other reply but to reject all claims to subjective, intuitional 'proof.'
Consider further:
Knowledge of a thing never requires an act of faith, but belief in a thing always necessitates faith. We are willing to believe many ideas on faith when we don't actually know those ideas are true.
And this brings up religious belief.
Since almost all religious persons are far removed from the origins of their religion, religion for almost all people is a matter of belief, not knowledge.
The founder of a religion may have seen an apparition of God (in which case she or he did not merely believe that God exists but knew it), but for all subsequent participants of that religion, God is a belief, not a datum of knowledge.
Belief-ideas are by definition doubtable, otherwise they would be knowledge-ideas.
Given the inherent doubt attending religious belief, it is remarkable that some religions insist that their followers claim a certainty of belief (a contradiction in terms).
In some religions, a Believer (a telling designation) absolutely must pose as a Knower.
'I know Jesus walked upon the surface of a deep fishing lake,' someone might say. But, really, we don't know that! It's a matter of belief and not knowledge.
Posing as Knowers was ever a cause of religious intolerance.
The world of religion will be much more serene when people accept religious ideas as mere beliefs that, not being in the category of 'knowledge,' can never impart certitude.
Faith cannot erase doubt, and indeed doubt is the condition for the possibility of faith.
Certainty expels faith. When I know for certain a lemon is sour, I don't need faith to believe a lemon is sour.
Faith corresponds to doubt: faith/doubt are the two sides of a coin.
Without the provocation of religious certainty, religionists lose one of the principal motives for engaging in religious intolerance.
Thank God mere belief offers the virtue of uncertainty.