The notion of the existence of a soul in Astronism is not as widespread of a belief as it is in another traditions of thought. The existence of an immaterial and immortal soul distinct from the body is most prominently found in transtellationism, which encompasses the belief that a person's soul transmigrates to the stars or to The Cosmos as a whole upon one's corporeal death. However, in all other parts of Astronism, there is very little emphasis placed on the soul which distinguishes Astronism from other religions and philosophies.

This is because other traditions centre their theologies around caring for one's soul to ensure entry into heaven. Instead, Astronism emphasises the significance of cultivating one's relationship to The Cosmos and it is this relationship that is provided with the most importance for Astronists.

Essentially, the state and extent of one's relationship to The Cosmos, its progeny, and its phenomena is tantamount to a person's morality, spirituality, and philosophicality. Although Astronism does not outrightly reject the notion of the existence of a soul, it places markedly less emphasis on the importance of one's soul and the cultivation of one's soul.

The term “soul” is mentioned in various instances in the Omnidoxy leading to the assumption that the concept of human beings have souls is a belief held within Astronism, however, the opposite is true. In Astronism, due to the principles of Cosmic Limitation, and the transience of our being, immortality is denied and therefore the existence of a soul present within us is rejected in Astronism.