For director Ingmar Bergman, upon what is cinema based?

For Bergman, cinema is based on the idea of exploring the
philosophical condition of humanity.  Bergman played with the idea of the human
metaphysical state in his films.  He did not necessarily believe in the structure of a
direct narrative, but rather used film as a way to explore philosophy and the impact it
has on human relationships.  For example, in The Seventh
Seal, the chess game with death is often seen as a exploration
of the philosophical state of mortality with death.  In Autumn
Sonata, the focus was the philosophical state of emotional
connections between individuals, particularly family members. 
Wild Strawberries was set with the
questions of what is love and why one needs it.  It is philosophical introspection that
guides Bergman's work and becomes the frame for it.  Bergman used the idea of philosophy
in his work and from this, there is greater understanding of how individuals are
impacted by it. This is not a traditional approach to filmmaking, as the traditional
needs of a script, character development, and plot structure are set amindst
philosophical inquiry.