The "silence of God" is a theme Bergman explored extensively in his previous work. According to author Paul Coates, "Persona" was the "aftermath" of that exploration. Gervais added that "Persona" and other Bergman films between 1965 and 1970 were not "God-centred". Gervais also quoted philosopher Friedrich Nietzsche as a guide to understanding "Persona": "Belief in the absolute immorality of Nature, in lack of purpose, and in meaninglessness, is the "affect" psychologically necessary once belief in God and an essentially moral order is no longer supportable".