The Republic
In Plato's Republic, Plato uses the illustration of a just city ("the republic") as a symbol for the state and nature of the human soul. In his references to Plato, Alfarabi explains the very same symbol, and he even uses his own version in "The Virtuous City." In this work, Alfarabi explains the reason for pursuing virtue in one's soul in terms of the effects of virtue in the city at large, utilizing the same city/soul analogy as Plato.
The Body as a Symbol for the Soul
In "Selected Aphorisms," in order to give the reader an idea of how he sees the soul, Alfarabi uses the symbol of the body. He says that just as illness is caused by the imbalance of bodily elements, soul sickness is caused by the imbalance of virtues and vices. He uses the symbol of the body for the next several aphorisms, saying that the health of the soul is both similar to and more important than the health of the body.
The Physician
In his analogical comparison of the soul and the body, Alfarabi claims that the physician is to the body what the statesman is to the soul. This comparison makes the physician into a symbol of healing, making sure that the reader knows that the proper function of a ruling statesman (king, etc.) is to ensure the health of his subjects' souls.
The Couch
Also in "Selected Aphorisms," Alfarabi uses the example of a couch, which turns into a memorable symbol for the potentiality of matter. He argues that before a couch is made, the separate parts that will be combined are simply matter that has the potential to be a couch. Only when they are skillfully combined and formed into the desired shape can it truly be called a couch.
Medical Books
In "Enumeration of the Sciences," Alfarabi discourses on the benefits and uses of political science. One of the benefits of political science, he argues, is that it informs the political scientist that there are two types of necessary skills for the virtue of excellent kingship: universal principles (knowledge) and the faculty resulting from enacting these universals (experience). He uses the analogy of a physician representing a statesman again, and he compares the acquisition of the universals to a physician learning the basic knowledge from his medial books. These books are thus a symbol of the source of the kind of knowledge that makes up universals.
