The cosmos is represented in a stratigraphic way: layers of land placed one on top of the other, producing parallel planes which do not physically communicate, except through the beings that inhabit them. What identifies these layers as members of the same class is their morphological base. Each level presents its own morphology composed of water, earth, trees and animals, varying only in form, size and number.

Although all the levels are designated migi, ‘earth,’ the difference between them is marked by their contents and the place they occupy in the structuration of the cosmos.
The Pirahã admit they do not know the exact number of levels. Despite the uncertainty in relation to the layers of earth composing the cosmos, people reduce this complex structure to a single model, retaining details and impressions for only five levels, which appear to make up the minimum possible form for representing their cosmology.

____________________ abaisi e ibiisi

____________________ abaisi e ibiisi

____________________ ibiisi

____________________ abaisi, kaoaiboge, toipe, ibiisi

____________________ abaisi e ibiisi

The lines correspond to the cosmic levels. Each of these is inhabited by particular beings (see the names on the right). The middle level is inhabited exclusively by ibiisi beings, the others by both abaisi and ibiisi, except for the level immediately below the middle, which also shelters the kaoaiboge and the toipe. Ibiisi is a generic designation for ‘human being:’ the Pirahã, Whites and other Indians are all ibiisi. What defines an ibiisi is its possession of a body with a specific form. The abaisi have the same general form as the ibiisi (they are anthropomorphic), but this form is imperfectly realized: they are defective or deformed beings. The kaoaiboge and toipe are posthumous transformations of the ibiisi, inhabiting the level immediately beneath the middle.

The Pirahã have an elaborate naming system directly linked to their cosmology. A Pirahã child receives its first name even before birth while still in the maternal womb. The received name has a close relation to fetal conception – it is the name of the body (ibiisi).

Another source of names comes from the abaisi beings who inhabit the cosmos. While the names linked to conception, origin names, are responsible for the creation of its matter, its support, the ibiisi (body), the names linked to the abaisi beings are related to its ‘soul,’ ‘destiny’ names.

The dead have an important role in the naming process. While the abaisi compete to provide names to give to the ‘soul’ or the possibility of a posthumous destiny, the dead in general compete for the responsibility to appear in the shamanic ritual, representing the name of the abaisi and passing them, via the shaman, to the ibiisi. The Pirahã belief is that by possessing an abaisi name, the transformation into kaoaiboge and toipe will be assured, each of these thus determining a destiny. Each abaisi name possessed by an individual refers to the possibility of his or her transformation into two beings, called kaoaiboge and toipe.

Kaoaiboge is a peaceful being that feeds on fruit and fish, a victim of the cannibalistic toipe. Thus, if an individual has eight abaisi names he or she will certainly have his or her destiny assured through transformation into eight kaoaiboge and eight toipe.
The relationship with enemies is another source of names. According to the Pirahã, a class of people designated euebihiai used to exist in their society. This category included the warriors/killers whose main objective was the killing of enemies and game, providing the ritual food to be consumed. Enemies produced names, game no, but both were treated in the some form in the rituals performed for their ingestion. The killers carefully observed the enemy before killing him in order to name him. The killer then gave the enemy the abaisi name possessed by a deceased person.

We can see that the logic of this type of onomastic practice was based on the physical similarity of bodies: an enemy body and a dead Pirahã body. Equal bodies, equal names. This logic is still employed today for naming strangers. In killing the enemy, the euebihiai acquired his name. He kept it for himself or transmitted it to other Pirahã.