Used in relation to the purpose that objects can assign to themselves, the concept was central to the works of Baruch Spinoza, Sigmund Freud, Jean-Paul Sartre, and Ernest Becker.
Brown, in his acclaimed Life Against Death, argues Freud's Oedipal complex is essentially the causa sui ("father-of-oneself") project, where, after the traumatic recognition that the subject is separate from the mother — that they are 'other' — they seek for reunification with the mother.
In traditional Western theism, even though God cannot be created by any other force or being, he cannot be defined as causa sui because such would imply the Spinozian pantheistic idea of 'becoming', which contrasts with the belief of scholastic theology that God is incapable of changing.
[2]The Catholic concept of...God as absolutely independent and self-existent by nature, and, consequently, all-perfect without any possibility of change from all eternity, is altogether opposed to the pantheistic concept of absolute or pure being [that] evolves, determines, and realizes itself through all time.
On the other hand, in the Japji Sahib, Guru Nanak (the founder of Sikhism) defined God as self-existent.