What is the difference between the soul (ruh), the self/psyche (nafs), and the body (jasad)? Do other creatures have souls? And does their ruling differ from the ruling concerning the human soul?

The spirit (ruh) and the soul (nafs) are synonymous, representing the energy that animates the body. When this energy departs the body through death, life ceases. It may also be called a 'nasama' (breath/being) and can refer to the essence of a thing or its attributes. The body is distinct from the spirit and soul; it is the perceptible physical form. Angels and jinn possess spirits that differ from human spirits, and similarly, animals and birds have spirits. As for plants, they have a type of life called 'hayat' (life), but it is not a 'ruh' (spirit).