The concept of a "spiritual world" refers to a non-material realm often seen as inhabited by spirits, souls, or higher awareness, existing beyond the physical. Authors such as Benjamin Fiske Barrett cast doubt on its reality and significance, while Christian D. Larson described it as a "transcendent kingdom of the soul," focusing on cosmic awareness.
Evelyn Underhill emphasized love and prayer as means to connect with this dimension, and Oliver Prescott Hiller associated it with states of consciousness that go beyond the material. The theme brings together varied viewpoints on being, awareness, and the divine, illustrating humanity's ongoing effort to grasp the deeper aspects of life.