Faith which does not doubt is dead faith.

The line expresses Unamuno’s characteristic view that authentic religious life is inseparable from inner conflict. For him, “faith” is not a settled possession or a set of propositions held without strain; it is a lived, existential struggle sustained in the face of uncertainty, suffering, and the fear of death. Doubt, in this sense, is not the enemy of belief but the condition that keeps belief morally and spiritually alive—preventing it from hardening into complacent dogma or mere social convention. A faith that never doubts may be “dead” because it no longer risks anything, asks anything, or wrestles with the human need for meaning and immortality.