The soul (nafs) is that heavenly essence which employs the body and uses its various organs to attain its goals and purposes. The soul has also other names as spirit (ruh), intelligence
(`aql), and heart (qalb) although these terms have other usages as well.
The most important faculties of the soul are:
1. The power of intelligence (al-quwwah al-aqliyyah)-angelic.
2. The power of anger (al-quwwah al-ghadabiyyah)-ferocious.
3. The power of desire (al-quwwah al-shahwiyyah)-animalistic.
4. The power of imagination (al-quwwah al-wahmiyyah)-demoniac.
The function and value of every one of these powers or forces of the soul is commonly well understood. If man did not have the power of reason, it would have been impossible for him to
distinguish between good and evil, right and wrong, true and false. If he did not possess the faculty of anger, he could not defend himself against attack and aggression.
If the force of sexual attraction and desire did not exist in man, the continued existence of the human species would be endangered. And finally, if man lacked the power of imagination, he
could not visualise universals or particulars, and he would be unable to make any inferences based on them.
With this explanation, the characteristics mentioned for each of the four human faculties are made clear and comprehensible. Reason is the guiding angel of man. The power of anger and
fierceness in man brings about ferocity and violence in him. His power of desire and passion propels him towards immorality and licentiousness.
And the imaginative power in man provides the preliminary material for the formation of demoniac schemes, plots and machinations. Now, if the faculty of reason is put in control of the
other faculties, it keeps them in their rightful place and moderates their excesses; they will work for the welfare of man and shall perform useful functions; otherwise, nothing except evil and
mischief will come of them.
The relationships of these four faculties of the human soul to one another are described in the following allegorical manner. Imagine a traveller on horseback accompanied by a dog and a man
who is a spy for the bandits. The mounted traveller represents reason. The mount represents desire and passion.
The dog represents the power of anger and fierceness. And the spy represents the imaginative power. If the traveller just mentioned is successful in controlling his mount, the dog, and the
spy, and in maintaining his authority over them, he shall arrive at his destination safely; otherwise, he will be destroyed.
The human soul is thus a stage or a battlefield on which there is a continuous struggle between these four powers. What would be the dominant characteristic and nature of an individual's
soul is entirely dependent on the outcome of this struggle. In other words, whichever of the four powers emerges victorious, it shall determine the character and inclination of the soul. That is
why some souls are angelic, some are animalistic and bestials and still others are demoniac.
In a hadith from Imam Ali (A), he is related as saying:
Surely God has characterized the angels by intellect without sexual desire and anger, and the animals with anger and desire without reason. He exalted man by bestowing upon him all of these
qualities. Accordingly, if man's reason dominates his desire and ferocity, he rises to a station above that of the angels; because this station is attained by man in spite of the existence of
hurdles which do not vex the angels.
