belief, a mental attitude of acceptance or assent toward a proposition without the full intellectual knowledge required to guarantee its truth. Believing is either an intellectual judgment or, as the 18th-century Scottish Skeptic David Hume maintained, a special sort of feeling with overtones that differ from those of disbelief. Beliefs have been distinguished according to their degree of certainty: a surmise or suspicion, an opinion, or a conviction. Belief becomes knowledge only when the truth of a proposition becomes evident to the believer. Belief in someone or something is basically different from belief that a proposition is true.