The Four Terms of the Soul

The soul is often referred to with these four terms of nafs, acal, kab, and ruh. Often the nafs is interpreted as self, some people say lower self. And then ruh, which is often translated as spirit, and acal,. which is translated as intellect and kab, which is the heart. So it can get rather confusing with all these terms, but I think what helps bring it into focus is if we try to understand from an Islamic perspective.