People always appeal to experience, reason, or faith in support of their beliefs.  We know what reason and experience are, but what is faith?  Is it an arbitrary impulse or surge of emotion?  Does it go contrary to all reason and experience, or can it be reconciled with them?  What do the great thinkers have to say about faith?

We may find some of the meanings of the term 'faith' by listening to our common speech.  For instance, we say of a friend, "I have faith in him," or "I believe in him." We also say, "I believe what he says," or simply "I believe in him."  In the first case, we affirm trust in or loyalty to a person.  In the second case, we assent to certain statements.  Both sense of 'faith' are expressed in the Bible and in post-Biblical writing.

In the Old Testament, the term 'faith' has a sense of absolute steadfastness, assurance, and loyalty.  This firm adherence to God, "the Everlasting Rock," is expressed throughout the Psalms and the Prophets.  In the New Testament, the meaning of personal trust and assurance in God is combined with the meaning of assent to the Gospel message about Jesus and his works.  There is also an emphasis on faith as a divine gift which enables the believer to lead a righteous life.

The great theologians and philosophers of the early and medieval Church are aware of faith as personal trust and adherence.  However, their main attention is directed to faith as an assent to definite statements--the "articles of faith." It is faith as knowledge and its relation to other sources of knowledge that is their concern.

Some early Christian thinkers consider faith and reason contradictory and irreconcilable.  But the main line of Christian thought before the Reformation is that faith and reason complement each other.  Augustine holds that faith illumines the mind and enables reason to grasp the essential truths about all reality.  "I believe in order that I may understand" is the way he puts it.  Faith is not against reason, for Augustine.  It is before it and beyond it.  It inspires the intellect to carry on its work.

Similarly, Thomas Aquinas holds that natural reason requires the direction and support of religious faith to obtain truth in its fullness.  For Aquinas, faith involves both the intellect and the will.  In the act of belief, the intellect is determined to assent by an act of the will.  To believe is "to think with assent."  In scientific knowledge, the intellect also assents to definite propositions.  But in the act of faith, the decision to assent comes from the will, while in scientific knowledge, the intellect assents of itself to what is demonstrably true.

A man may or may not assent to the essential doctrines of the Christian religion.  Whether he does or does not is a matter of his will--of personal decision, not of intellectual perception alone.  But in scientific matters, the intellect must assent to what is either self-evident or demonstrably true.

Aquinas holds that reason can attain certain basic truths about God's existence and nature, but that faith makes man's grasp of these truths both more certain and more readily attainable.  He holds, further, that full knowledge about God and man's way to ultimate salvation requires faith in divine revelation.  Such faith, according to Aquinas, is a gift of God's grace.  That is why faith, along with hope and charity, is called a theological or supernatural virtue.

Other Christian thinker consider human reason incapable of attaining truths about God and hold that man's basic religious knowledge comes through faith alone.  Luther emphasizes the passive aspect of faith as an unearned gift of divine grace, which regenerates and enlightens man.  Before this happens, man and his natural faculties are corrupt and blind, incapable of apprehending any truths about God.

All these religious writers, however, would distinguish faith from what William James calls "the will to believe." For James the philosopher, whether or not we hold certain basic religious beliefs is entirely a matter of our own free will.  For the theologians, God himself is the ultimate source of our will to believe when we believe in the things that God has revealed to man.