Belief, in ordinary usage, means mental assent on grounds other than direct personal knowledge, insight, or complete demonstration. It admits of every degree of conviction from the feeblest to the very strongest (Century Dictionary). In a religious sense, belief is often used as a synonym of faith, and is sometimes used to include the absolute conviction or certainty which accompanies knowledge.
The quality of belief is clearly and directly related to the object of belief. In an age of deep religious insight, feeling, and experience, when the object of belief is God and the things of God, belief means much, even that faith which removes mountains. In an age of dogmatism, when the object of belief is an opinion or even conviction about God rather than God Himself, belief usually means much less. In an age of scholasticism, when the object of belief is a theory or philosophy of religion rather than the primal facts of religion, belief necessarily means very little. In an age of criticism, when the human mind is unable longer to believe its own theories about "divine realities," and has not yet re-discovered God as the object of belief, belief means only a formal assent to things no longer really believed. Unbelief has usurped the place of belief; but the insufficiency of unbelief speedily necessitates a new era of faith when God, divine reality, again becomes the object of belief.
The religious experience of the individual, as well as the history of religious sects and movements, may, and often does, correspond in a general way to these ages and cycles of primitive religious faith, dogmatism, scholasticism, and criticism. This does not mean that the individual and the race are doomed to such an endless circle, for as belief becomes knowledge, understanding, or science, there is no longer a necessity or possibility for the struggle of belief against unbelief; but, until all true belief is swallowed up in understanding and all false belief is destroyed, belief and understanding will appear side by side, and those who have most understanding will also have most faith, while those who have least acquaintance with God will have the least faith.
