Paul Tillich on Faith

"Faith is a concept--and a reality--which is difficult to grasp and to describe. Almost every word by which faith has been described ... is open to new misinterpretations. This cannot be otherwise, since faith is not a phenomenon besides others, but the central phenomenon in man's personal life, manifest and hidden at the same time. Faith is an essential possibility in man, and therefore its existence is necessary and universal.... If faith is understood for what it centrally is, ultimate concern, it cannot be undercut by modern science or any kind of philosophy.... Faith stands upon itself and justifies itself against those who attack it, because they can attack it only in the name of another faith. It is the triumph of the dynamics of faith that any denial of faith is itself an expression of faith, of an ultimate concern."- Paul Tillich, Dynamics of Faith