Aki: All life is born of Gaia and each life has a spirit. Each new spirit is housed in a physical body. Doctor?

Dr. Sid: Go on.

Aki: Through their experiences on Earth, each spirit matures and grows. When the physical body dies, the mature spirit, enriched by its life on Earth, returns to Gaia, bringing with it the experiences, enabling Gaia to live and grow.

z filmu Final Fantasy:Spirits Within