Gate 150, Chapter 9
The different definitions of Nefesh soul.
The Nefesh soul is also called the Animal Soul (Nefesh Behemit). This soul is under the influence of physical matter. It has cravings for sensation, but at the same time, is not malevolent. Its desire for gross physicality is called bad (yetzer hara), but it is not evil, in that it is malicious, and intentionally harmful.
There is also a higher Nefesh soul that emanates from the higher, invisible, physical dimensions of Asiyah. This level of Nefesh emanates from the Ofanim angels who control this domain.
Above all Nefesh, at a specific point in human biological (and psychological) development, there comes into us the Ruah level of soul. This is the emotional component, be it for good or bad. It is this Ruah soul that introduces the emotional content. The evil herein is the malicious intent to intensionally do harm.
Above this, there is yet the Neshama level of school. Although this level is not discussed in the text, we comment on it anyway, in the spirit of Rabbi Vital, the author of the Etz.
50 minute lesson.