Western Philosophy
Alfarabi extensively studied the writings of Plato and Aristotle, and his works reflect this knowledge by rephrasing and incorporating the ideas of these ancients into his own philosophy. For example, in "The Political Regime," Alfarabi begins with a description of the order of the universe in a style that is distinctly influenced by Plato, earning the classification "Neoplatonic." Additionally, some of Alfarabi's books are entirely based on foundational works of Western philosophy, such as his "Summary of Plato's Laws" as well as "The Harmonization of the Two Opinions of the Two Sages: Plato the Divine and Aristotle," in which he compares the philosophies of Plato and Aristotle and shows how they are actually compatible, in opposition to the views of most scholars. Whether explicit or implicit, the impact of Western philosophy on that of Alfarabi is remarkable.
Nature
Alfarabi's works often deal with the nature of the world and of life, investigating its source and finality while pondering its meaning. He goes about his exploration of nature in a distinctly Aristotelian way; in "Enumeration of the Sciences," he breaks down natural science into five categories (language, logic, mathematics, physical science, and political science) and then gives a detailed description, interpretation, and analysis of each one. In other works, such as "The Political Regime," he also gives other remarks about the nature of nature, such as his order-based view of the universe proposed in the first half of the book.
Humanity
As a philosopher drawing from the ancient Greeks, as well as being a Muslim, Alfarabi also wrote extensively on the nature of humanity and the human soul. In "Selected Aphorisms," for example, he echoes and reformats Plato's views in The Republic concerning the division of the soul and the correct ordering of the parts in order to create a healthy balance. The second half of "The Political Regime" also deals with humanity and the soul; Alfarabi's mission is to explain the nature of the soul and emphasize its importance in the nature of Plato and, it may be argued, Aristotle as well.