Philosophers and Sufis paid a great deal of attention to analyzing the nature of the human self. Avicenna and others wrote books on psychology, in Arabic ilm al-nafs, “knowledge of the soul.” Given the routes that modern psychology has taken, it would be more appropriate to translate this term as “spiritual psychology,” for its whole purpose was to help souls attach themselves to the realm of the spirit. As for Sufi teachers, they were typically spiritual psychotherapists. They taught disciples how to conform themselves to the models of human perfection set down by the prophets, taking Muhammad’s Sunnah as the template for transformation by love. In their reading, the Sunnah embraces not only the Prophet’s outward and inward practices, but also the various dimensions of his self—his character traits, virtues, understanding, wisdom, love, and realization.
In Arabic, the word nafs, “soul,” also means “self.” In saying “the thing itself” or “God Himself,” one uses the same word, nafs. The philosophers employed it to designate any kind of awareness and consciousness, any sort of interiority short of the full actualization of the intellect (aql). Following in the footsteps of the Greeks, they held that there are different sorts of souls, arranged hierarchically, and that they can be discerned by analyzing the faculties that become manifest through the activities of living things. The Arabic word for faculty, quwwa, means “strength, power, potency, potentiality.” We can talk about vegetal, animal, and human souls because in each case, specific potencies appear to us that we cannot discern at a lower level. Plants are differentiated by certain potencies not found in minerals, such as growth and reproduction. Animal souls possess additional faculties, such as volitional movement. Human beings add speech and reason.
Philosophers sometimes used the word nafs interchangeably with quwwa. They would then speak of the animal potency, meaning the animal soul, for the soul is simply the sum total of a being’s inner potencies. The animal soul includes the potencies of plants but falls short of human potency. The basic understanding was that little by little, as potencies intensify, so also do aware- ness and consciousness, leading finally to the summum bonum of the human state, which philosophers often called the actual intellect (al-‘aql bi’l-fi‘l). They described it as the achievement of conjunction (ittisal) with the active, or agent, intellect (al-‘aql al-fa‘al). This they understood to be a universal, cosmic aware- ness, the first manifestation of the Divine Reality. Historians of philosophy recognize it as the nous of Plotinus, the first emanation of the One. One can see another parallel in the notion of purusha in the Samkhya school of Hindu philosophy.
It is not too difficult to see that as people gradually ascend toward perfect intelligence and awareness, it becomes ever more difficult to explain what is going on. Inanimate things can be analyzed endlessly, but the moment we try to pin down exactly what defines life, we start running into puzzles, a fact especially obvious in medicine. Science meets inscrutability as soon as it tries to get inside living things, especially human beings. Despite the proliferation of sciences and ologies in modern times, the human self remains as much a mystery as ever.
The Muslim philosophers maintained that once full human potential is realized—as in the case of the great prophets—the soul is no longer a soul but rather an actual intellect. This does not imply that the intellect has lost the faculties and powers of the vegetal, animal, and human souls, but rather that those have now come to be fully realized. The philosophers called the soul’s realization of its potential by a variety of names, including deiformity and theomorphism (ta’alluh, from the same root as allah). They understood it to mean the actualization of the divine form in which man was created.
Early Sufi writings made no attempt to engage in systematic analyses of the soul, preferring instead to meditate on its nature, in keeping with various Qur’anic verses and prophetic hadiths. In talking about the soul, they used several words besides nafs, including heart (qalb), spirit (ruh), and intellect (‘aql). At the beginning of Book 21 of Giving Life, which is devoted to explaining the marvels of the heart, Muhammad Ghazali says that those four words denote the same reality, that is, the human subtlety (al-latifat al-insaniyya), but in each case from a different standpoint.
The attribute latif, “subtle,” is employed to designate invisible, impalpable realities pertaining to the spiritual realm. It is contrasted with gross or dense (kathif ), meaning the dark, heavy, concrete things of the sensory realm. As a divine name, latif means not only subtle and, hence, beyond any of the densities and imperfections of the created realms, but also gentle, mild, forgiving, merciful. God’s gentleness has ontological precedence over the multiplicities and distinctions that appear when things emerge from subtlety and enter into density and darkness.
By using the word subtlety to name the inner reality of the self, authors are saying that whatever the human subtlety may be, it cannot be pinned down by definitions, much less analyses of biological or physiological causality. The human subtlety does not derive from the dense elements found in the corporeal realm, quite the contrary. Physical things are sediments or shadows of the subtle realities that lie beyond. “As above, so below,” as the ancient maxim put it. The philosophical notion of hylomorphism—that all things are compounded of matter (madda) and form (sura)—goes back to the self-evident fact (for Muslim philosophers and theologians, at least) that all perceived qualities, characteristics, traits, and attributes pertain not to the matter of things, but rather to their forms, which are subtle forces that employ matter as loci of manifestation. Ultimately, all forms go back to God, whom the Qur’an calls the Form-Giver (mu- sawwir) and the philosophers called the Bestower of Forms (wahib al-suwar).
The best way to gain an understanding of the words that designate the human subtlety—words whose semantic fields often overlap or coincide—is to see how they are used in context. There is no agreement on definitions, but there are common themes, such as the distinction between the corporeal and the spiritual or the multilayered-ness of the noncorporeal realm.