The word 'nagual' belongs to the Nahuatl language. Also known as Mexican language, Nahuatl was the language spoken by the people now known as Aztecs and their predecessors (the Colhua, Tecpanec, Acolhua, and the Toltecs).
Nagual is the counterpart of tonal. Together, tonal and nagual are the two sides of the duality always present in the vision of the world of many indigenous peoples of Mexico.
In Aztec mythology, a Nagual was a totemic or tutelary spirit in the shape of an animal or a plant. Every god and human had his personal Nagual with whom he shared his fate until death.
The term was used by Carlos Castaneda in his books to describe a person who is able to lead people to new areas of perception. Currently, the term nagual is being used to describe a shaman or one who follows a path of knowledge such as the Toltec Path of Don Miguel Ruiz.
In Castaneda's works, nagual is the title or epithet of Don Juan and later Castaneda himself. Besides being a title or function of a person, nagual refers to the idea of the unknown and unknowable. Nagual in this sense is the sea of possibility that surrounds all forms. It is intrinsically beyond form. If something can be named, it is not the nagual, it is a part of the tonal. Nagual is beyond description. We could compare it to the Eastern Tao in the sense that anything that can be described is not it. We could also compare it to the Ungrund of Jacob Boehme. In more modern terms, we could compare the nagual to the zero point field. All form, whether of thought or of matter is tonal, whether it be known to or knowable by man. Only the absolutely unbounded is the nagual.
Red Elk, an Inter-Tribal Medicine Man, who is a self-described half-breed Native American/white, of both the BlackFeet and Shoshoni Nations, sees the human totality as consisting of three aspects -- body, soul, and spirit. The first, second and third attentions that Carlos Castaneda talks about in his writings may also correspond to these three aspects of the human totality. The first attention may refer to the attention governing the physical body, the second attention may refer to that attention which relates to the human soul and the third attention may refer to that attention that relates to the human spirit.
According to Red Elk, modern day Christianity erroneously equates spirit with soul. Spirit, says Red Elk, is the true Nagual and the Nagual is distinct from the soul. The Nagual, according to Red Elk, is what Christians call the spirit.
The Nagual most likely corresponds to the Sanskrit term Purusha or "pure consciousness." However, direct correspondences between similar terms in different systems of thought can never really be exact.
If the Nagual can be considered the spirit, then it is the Nagual that connects the human totality with that creative power that endows man with that proud title "Made in the image of God."
According to Red Elk, The Nagual is that part of the human totality which reincarnates and it is not the soul that reincarnates. He views the soul as something that must be formed anew within each life. He sees the soul as a mind that has organized itself into a fully functioning independent unit. A fully formed soul would correspond to a fully transformed mind. In other words, a fully formed soul is a mind which has been transformed into an organized and balanced unit so as to be able to "receive the spirit" and become a functional instrument of the Nagual.
Another way to say it is that the soul is a stable energetic structure that evolves out of mind, which reconciles the world of spirit with the world of matter, and is able to channel energies of a higher order into our present moment of experience.
The Nagual may correspond to the word "Geist" as used by Hegel, which gives Man that "latent potential" to form a human soul which would allow him to recieve the Great Spirit, which makes him truly "in the image of God." The Nagual is the uncreated in the created, the impossible latent in the possible that gives Man his soul potential to form a living soul and receive the Great Spirit allowing him to spiritualize the existing world while simultaneously allowing him the possibility of realizing his own essential nature as a human being.
Thus, from Red Elk's particular perspective, it is the Nagual, our "soul potential," which really reincarnates from life to life and the actual soul must be formed anew in each separate life.
Don Juan in Carlos Castaneda's book 'Tales Of Power' speaks of the nagual as:
"The nagual is the part of us which we do not deal with at all. The nagual is the part of us for which there is no description--no words, no names, no feelings, no knowledge. It is not mind, it is not soul, it is not the thoughts of men, it is not a state of grace or Heaven or pure intellect, or psyche, or energy, or vital force, or immortality, or life principle, or the Supreme Being, the Almighty, God--all of these are items on the island of the tonal" [End Quote]