A Spirit (スピリット, Supiritto?) refers to the spiritual energy in Final Fantasy: The Spirits Within needed to create the anti-wave to solve the Phantom problem. In a broader sense, Spirits refer to spiritual energy within all living things, binding the immortal soul and individuality to its living host.
Phantom SpiritsEarth after their genesis. The Phantoms Spirits, commonly referred simply as "Phantoms", appear ethereally crimson. Although deemed as the evil which destroys life, they are actually confused spirits with no purpose to exist after death.
Gaia SpiritsDr. Sid and Aki Ross. The eight Spirits they have been searching for must be combined and when completed, the Gaia Spirits will neutralize the Phantom Spirits.
Dr. Sid is an advocate of bio-etheric research — study on spiritual energy within lifeforms. A genius in wave theory, he discovered that each Spirit has a wave pattern. In studying the wave emitted by Phantoms, he discovered that all Phantoms carry similar wave patterns. As opposing bio-etheric waves placed one over the other cancel each other out, he believes a wave pattern assembled from Earth's lifeforms may disable the Phantoms.
The wave pattern has to be assembled from different species, as there is no lifeform that carries the same basic wave. Due to the Phantom invasion many living organisms have been obliterated. Dr. Sid studied all remaining lifeforms and found that the wave may be assembled by gathering eight lifeforms that carry these waves, named Spirits.
Assembling the wave patterns creates the perfect match to the alien Phantom's wave pattern. Aki Ross transmits the waves through Gray Edwards, her lover who sacrifices his life to finish her and Dr. Sid's work. Since the Phantoms are Spirits, or ghosts, themselves, the waves neutralize each other and the Phantoms are "erased from existence", now at peace and with help from the purified Gaia, ascend to the afterlife as they should have done when their world was destroyed.
spirit derives from Latin spiritus, "breath", has many meanings most relating to a non-corporeal substance contrasted with the material body. The word is often used metaphysically to refer to the consciousness or personality. The notions of a person's spirit and soul may overlap, as both are understood as surviving the bodily death in religion and occultism. "Spirit" can also have the sense of "ghost", i.e. a manifestation of a deceased person. The term may also refer to any incorporeal or immaterial being, such as demons or deities.The word