There are always at least two viewpoints at any time. You can face the past or the future, origin or destination. You observe and hear what is outside of you or reflect upon your inner senses and feelings. You are always held in between these two zones and desire balance and stability. This tension enables us to grow and evolve physically, mentally and spiritually.
Everything that exists has an outer and an inner facet, which are in balance. For a youngster, most experiences are due to sensory stimulation. For an adult there is outer and inner consciousness. For an awakened being the outer and inner are seamlessly bound together due to the emergence of the light of the Oneness.
Discriminating between outer and inner is the first step to realizing their inseparability in essence.
From Spectrum of Reality by Shaykh Fadhlalla Haeri