What Is "First Philosophy"? How Aristotle's Most Mysterious Book Shaped Islamic Thought

Imagine you’re a scholar in Baghdad, around the year 900. You’ve heard that there’s this ancient Greek thinker, Aristotle, who wrote about everything—animals, the sky, logic, the soul. But there’s one book of his that nobody can quite agree on. It’s called the Metaphysics—which literally means “the things after the physics”—and even the title is a kind of accident. Someone stuck the book after Aristotle’s physics writings, and the name just stuck.

But here’s the strange thing: when people actually open this book, they find Aristotle talking about at least three different things. Sometimes he says he’s studying “being as such”—the most general features of anything that exists. Sometimes he says he’s studying the “first causes” of everything—the deepest explanations for why things are the way they are. And sometimes he says he’s studying God—an eternal, immaterial being that sets everything in motion. Are these the same science? Or three different ones? And if metaphysics is supposed to be the highest form of knowledge, what exactly is it knowledge of?

For about 500 years, philosophers writing in Arabic—Muslims, Christians, Jews, and others—argued about this question. And their answers shaped not just how people thought about philosophy, but about God, the universe, and whether reason and religion could ever get along.

Three Ways of Reading One Book

When Aristotle’s Metaphysics was translated into Arabic in the 9th and 10th centuries, philosophers had to decide what to do with it. Roughly speaking, they took three approaches.

The first approach was taxonomical: you figure out where metaphysics fits among all the other sciences. Is it the last thing you learn, because it’s the hardest? Or the first, because it deals with the most fundamental realities? Different philosophers answered differently, and their answers revealed what they thought metaphysics was really about.

The second approach was exegetical: you write a commentary explaining Aristotle’s text line by line. Some commentators stuck very close to the Greek original. Others paraphrased freely, adding their own ideas. The choice was itself a philosophical statement.

The third approach was adaptive: you write your own treatise on metaphysics, using Aristotle as a starting point but going your own way. The most famous example of this—and the most influential—came from a Persian philosopher named Avicenna (Ibn Sīnā), who lived from 980 to 1037.

The Kindian Approach: Metaphysics as Theology

The first major Arabic philosopher to tackle the Metaphysics was al-Kindī, who died sometime after 870. He had a pretty clear agenda: he wanted to show that Greek philosophy and Islam were compatible. For al-Kindī, metaphysics was basically the study of God—a kind of philosophical theology. He focused on the parts of Aristotle’s book that talk about the divine, and he ignored or downplayed the more general stuff about “being as such.”

This made sense strategically. If you could show that Aristotle’s God was basically the same as the God of the Qur’an, then philosophy looked like a friend to religion, not a rival. Al-Kindī even argued that philosophy was the discipline that gives “full articulation and rational explanation to the miraculous conciseness of the prophetic message.” In other words, prophets speak in beautiful, compressed language; philosophers unpack it.

But there was a cost. By reducing metaphysics to theology, al-Kindī was ignoring huge chunks of Aristotle’s text. And he was making philosophy dependent on religion—which some later philosophers thought was a mistake.

Al-Fārābī’s Revolution: Universal Science

A philosopher named al-Fārābī, who died in 950, took a very different approach. He wrote a short but explosive work called On the Goals of the Sage—“the Sage” being Aristotle. In it, he argued that everyone before him had misunderstood the Metaphysics. The book wasn’t just about God. It was about everything that exists, considered as something that exists.

This is a subtle but huge shift. Al-Fārābī claimed that metaphysics is the universal science of “being qua being”—being considered just as being, not as this or that kind of thing. Physics studies moving bodies. Mathematics studies numbers and shapes. But metaphysics studies what all of these have in common: the fact that they are. Only after establishing that universal science does it go on to talk about God—because God is a special kind of being, the first cause of everything else.

Think of it this way: if you wanted to understand everything that exists, you’d need to study particular things—trees, stars, people. But you’d also need to ask: what does it mean for something to exist in the first place? Is existence the same thing as being a tree? Or is it something that trees have? These are the questions that metaphysics, as ontology (the study of being), is supposed to answer.

Al-Fārābī’s view had a radical implication. If metaphysics is about being as such, then it’s more fundamental than religion. Religion tells you about God, but metaphysics tells you about the framework within which God exists. Philosophy doesn’t need religion to justify itself. It stands on its own.

Avicenna’s Synthesis

Avicenna is the giant of this whole story. He read al-Kindī, he read al-Fārābī, he read the commentaries of the Baghdad Aristotelians—and then he wrote his own version of the Metaphysics, which he called The Science of Divine Things. It’s part of a massive encyclopedia called The Cure (or The Healing), and it’s one of the most influential philosophy books you’ve never heard of.

Avicenna did something clever. He agreed with al-Fārābī that metaphysics is the science of being as such. But he also agreed with al-Kindī that it’s about God. How can both be true?

His answer: God is the goal of metaphysics, not its subject matter. The subject matter is “the existent qua existent”—everything that exists, considered as existing. But the goal—what the science is ultimately trying to understand—is the first cause of existence, which is God. So metaphysics is both ontology and theology, but in different senses. It starts with being in general, and ends with the source of being.

This may sound like a technical distinction, but it had enormous consequences. For one thing, it allowed Avicenna to claim that metaphysics is the “queen of the sciences”—the discipline that gives principles to all other fields. Physics assumes that matter exists. Mathematics assumes that numbers exist. But only metaphysics asks what existence itself is. And only metaphysics can prove that God exists—not by appealing to motion (as Aristotle did in his physics) but by pure philosophical reasoning about being.

Avicenna also introduced a distinction that became famous: the distinction between essence and existence. For most things, what they are (their essence) is different from the fact that they are (their existence). A unicorn has an essence—it’s a horse with a horn—but no existence. A real horse has both: its horseness and its actual being in the world. But God, Avicenna said, is the one being whose essence is its existence. God doesn’t just have existence; God is existence itself. This was a way of saying that God is absolutely unique and necessary—unlike everything else, which could either exist or not.

What Happened After Avicenna

After Avicenna, Aristotle’s Metaphysics gradually faded from center stage. Philosophers stopped commenting on it directly. Instead, they commented on Avicenna’s works. His Book of Pointers and Reminders became the standard textbook for centuries. The Science of Divine Things was copied and recopied and covered with marginal notes.

Not everyone accepted Avicenna’s synthesis. Some philosophers, like Averroes (Ibn Rushd), wanted to go back to a “purer” Aristotle. Some theologians, like al-Ghazālī, attacked philosophy itself, arguing that reason couldn’t answer the deepest questions. Others, like Suhrawardī, tried to replace Avicenna’s approach with an “illuminationist” philosophy based on light and intuition rather than being.

But everyone argued with Avicenna. Even his critics adopted his vocabulary and his problems. The distinction between essence and existence, the relationship between ontology and theology, the question of whether metaphysics can prove God’s existence—these became the standard topics of Islamic philosophy for centuries, all the way down to the 19th century.

Why This Matters

This whole story raises a question that still matters: Can reason and religion be friends? The Arabic philosophers had three answers.

Al-Kindī said yes, but only if philosophy limits itself to explaining what religion already says. Al-Fārābī said yes, but only if philosophy is independent and religion is seen as a simplified version for people who can’t handle demonstrations. Avicenna said yes, by showing that philosophy and religion talk about the same God, but in different languages.

The debate never really ended. In our own time, people still argue about whether science and religion are compatible, whether reason can prove God’s existence, and whether there’s a single “first philosophy” that underlies everything else.

And there’s a deeper puzzle here. If metaphysics is about “being as such,” then it’s about the most general features of reality—the things that are true of everything. But can you really study “being” without studying particular beings? Can you ask what existence means without asking what exists? The Arabic philosophers thought you could, and they built elaborate systems to prove it. But they never quite agreed on what those systems looked like.

That’s the strange thing about metaphysics: the more fundamental it tries to be, the harder it is to pin down. Maybe that’s why Aristotle’s book, after all these centuries, is still called “the book nobody understands.”

Appendices

Key Terms

Term	What It Does in This Debate
Metaphysics	The study of “being as such” and/or the study of God—the fundamental science that tries to understand what exists and why
Ontology	The part of metaphysics that studies being in general, without focusing on any particular kind of being
Theology (in this context)	The part of metaphysics that studies God as the first cause of everything
*Being qua* being**	Things considered just as things that exist, not as trees, people, numbers, etc.
Essence	What a thing is—its definition, its “whatness”
Existence	The fact that a thing actually is—its “thatness”
First Cause	The ultimate explanation for why anything exists at all; identified by many Arabic philosophers with God

Key People

Aristotle (384–322 BCE): The ancient Greek philosopher whose book Metaphysics started the whole debate; known as “the First Teacher” in the Arabic tradition.
Al-Kindī (died after 870): The first major philosopher working in Arabic; argued that metaphysics is basically theology and that philosophy supports Islam.
Al-Fārābī (died 950): A philosopher who argued that metaphysics is the universal science of being, not just theology; wanted philosophy to be independent of religion.
Avicenna (Ibn Sīnā) (980–1037): The most influential philosopher in the Islamic world; created a massive synthesis that became the new standard text for metaphysics.
Averroes (Ibn Rushd) (1126–1198): A later philosopher who wrote commentaries on Aristotle and strongly criticized Avicenna for deviating from the original.

Things to Think About

If you could study one science that would tell you the most fundamental truths about everything—what would that science be, and what would it study? Can you study “being in general” without studying specific things?
Avicenna said that for most things, their essence (what they are) is different from their existence (that they are). Think of something that doesn’t exist—like a dragon or a perfectly fair society. Does it have an essence? Can you say what something is if it isn’t?
Al-Fārābī thought philosophy was superior to religion because philosophers use demonstration (proofs) while religion uses poetry and persuasion. Do you think this is fair to religion? Could there be truths that can’t be proven by demonstrations?
The Arabic philosophers all agreed that metaphysics was the “queen of the sciences.” But what if there is no single science that underlies all the others? What if physics, mathematics, and ethics each study totally different kinds of things, with no common ground?

Where This Shows Up

School subjects: When a math teacher asks “what is a number?” or a science teacher asks “what is matter?”—they’re doing something like metaphysics for their own fields.
Arguments about God: The question “Can you prove God exists using reason alone?” is still debated today, and the arguments often trace back to Avicenna’s proof.
Science fiction: When stories ask “What is reality?” or “What does it mean for something to exist?”—like in The Matrix—they’re raising metaphysical questions.
Everyday life: When you argue about whether something is “real” or “just in your head,” or whether there’s a difference between what something is and the fact that it’s here—you’re doing metaphysics without knowing it.