How Arabic Philosophers Changed the Way Europeans Think

The Puzzle That Started It All

Imagine you’re a student in Paris around the year 1250. You’ve just enrolled at the university, and your teacher tells you that you’ll be studying Aristotle—the greatest Greek philosopher who ever lived. There’s just one problem: Aristotle wrote in Greek, and almost nobody in Europe can read Greek anymore. The only versions of his works you have are translations… from Arabic.

This is strange, right? How did Arabic translations of Greek philosophy end up shaping European universities? And stranger still: the Arabic philosophers didn’t just pass along Aristotle’s ideas. They added their own, argued with him, and invented new concepts that European thinkers would wrestle with for centuries.

This article is about how that happened—and about some of the weird, difficult, and powerful ideas that came along with it.

How Greek Philosophy Got an Arabic Detour

Here’s a quick piece of history that might surprise you: between roughly 750 and 1000 CE, the most advanced philosophy and science in the world was being done in Arabic. Scholars in Baghdad, Cordoba, and Cairo translated Aristotle, Plato, and other Greek thinkers into Arabic, then wrote their own commentaries and new works. Meanwhile, in most of Europe, very few people could read Greek, and the old Roman learning had mostly collapsed.

So when Europeans finally wanted to study philosophy again—around 1100–1200 CE—they had to get it from the Arabic world. A massive translation project began, mostly in Spain (which had large Muslim and Jewish communities), where Christian scholars worked with Jewish and Muslim colleagues to turn Arabic philosophy books into Latin. By 1255, the University of Paris required all students to read Aristotle’s works—and the main commentaries they used were by Arabic philosophers.

This is one of those moments in history where everything could have gone differently. If those translators hadn’t done their work, European philosophy might have looked completely different.

The Big Fight About the World: Did It Always Exist?

One of the most explosive ideas that came from Arabic philosophy was this: maybe the world has always existed.

You might think this is obviously wrong—didn’t God create the world at some point? But a group of Arabic philosophers, especially a man named Avicenna (who lived from 980 to 1037), argued that if God is perfect and unchanging, then God would always have been creating. The universe would have no beginning in time. It would be eternal.

Let’s think about what this means. If you believe God is perfect, you might think: a perfect being doesn’t suddenly decide to do something new. A perfect being just is, always. So creation isn’t a one-time event—it’s eternal. The universe never started existing; it has always existed, caused by God in the same way that light always comes from the sun.

This got Avicenna and another philosopher, Averroes (who lived from 1126 to 1198), into serious trouble with religious authorities. In 1270 and 1277, the bishop of Paris officially condemned the idea that the world is eternal. But that didn’t stop philosophers from discussing it. For centuries, European thinkers kept returning to the arguments Avicenna and Averroes had made.

The Strangest Idea: One Mind for Everyone

Now here’s an idea that might really stretch your brain.

Averroes argued that there is only one single intellect for all human beings.

What does that mean? Think about it like this: when you understand something—say, the concept of a triangle—your understanding seems personal. You understand it. But Averroes thought that the “intellect” that does the understanding isn’t really yours. It’s one shared thing that all humans tap into, like a single light bulb that shines into many rooms. When you think, you’re not really the one thinking—you’re just temporarily connected to the universal intellect.

This is called the “unicity thesis” (unicity just means “oneness”). Most people found it crazy. The Catholic Church condemned it. But some philosophers loved it. A group called the “Averroists” defended it for centuries.

Why would anyone believe this? Well, Averroes was trying to solve a real problem. How do we know universal truths (like mathematical facts) that are the same for everyone? If your mind and my mind are completely separate, how do we both grasp the same idea? Maybe, Averroes thought, the ideas aren’t in our individual minds at all—they’re in one shared mind that we all access.

The main objection came from Thomas Aquinas (a famous Christian philosopher who lived 1225–1274). He said: if there’s only one intellect for everyone, then “this individual man thinks” doesn’t make sense. When you learn something, it should be you doing the learning, not some universal mind.

This debate—about whether thinking is personal or shared—never really ended. You can still find versions of it today, in questions about whether computers could have a shared intelligence, or about what consciousness really is.

The Flying Man: Avicenna’s Thought Experiment

Avicenna came up with a famous thought experiment that still appears in philosophy classes today. He called it the “Flying Man.” Here’s how it goes:

Imagine you’re created all at once as an adult, floating in empty space. You can’t see anything, hear anything, or feel anything. You’re just… aware. Would you still know that you exist?

Avicenna thought the answer was yes. You would know you exist even without any senses telling you about your body or the world. This, he argued, shows that the soul (or the self) is not the same thing as the body. Your awareness of yourself doesn’t depend on your body.

Europeans found this idea fascinating. It became one of the sources for later arguments about the mind being separate from the brain—an idea that philosophers and scientists still argue about today.

The Inner Senses: More Than Five

You probably learned that humans have five senses: sight, hearing, touch, taste, smell. But Arabic philosophers added more.

Avicenna argued that we have “internal senses” that process information from the outer senses. One of the most interesting is something he called estimation (in Arabic, wahm). Here’s what it does:

A sheep sees a wolf. The sheep’s eyes see the wolf’s shape and color. But the sheep also perceives something else: the wolf is dangerous. It should be fled from. That “dangerousness” isn’t a color or a shape—it’s an intention, a meaning that the sheep grasps directly.

Avicenna called these perceived meanings “intentions” (from the Arabic word ma’nan, which means something like “concept” or “meaning”). The idea is that animals (and humans) don’t just perceive raw data—they perceive what things mean.

This might sound obvious now, but it was a big deal in its time. It raised questions like: Do animals really “think”? Do they make judgments? Can they grasp meanings without language? Philosophers argued about this for centuries. Some said estimation was only for animals; humans have something higher called “cogitation.” Others said animals couldn’t truly judge at all, since judgment requires language.

The Great Debate: Essence vs. Existence

Here’s another Avicennian idea that shook up European philosophy: the distinction between essence and existence.

What does a thing mean? That’s its essence. What does it mean for a thing to be? That’s its existence.

Avicenna said these are different. Take “horseness”—the essence of a horse. In itself, Avicenna argued, “horseness” is neither universal (in your mind) nor particular (in the real world). It’s just horseness. Only when it exists somewhere does it become either a universal idea in your head or a particular horse in a field.

This might seem like splitting hairs, but it had huge consequences. It meant that existence is not just part of what something is. A thing could be fully defined in your mind (its essence) without actually existing. Existence is something added to essence.

European philosophers took this and ran with it. Some, like Thomas Aquinas, used it to talk about God: God is the one being whose essence is existence. Everything else just happens to exist; God must exist. Others, like Duns Scotus (who lived 1266–1308), developed their own versions of the idea. And some rejected it completely, arguing that the distinction between essence and existence didn’t make sense.

This debate—about whether “what something is” is different from “that it is”—continued for centuries. It’s still alive in some forms of philosophy today.

The Active Intellect: Where Do Ideas Come From?

One more Avicennian idea that Europeans couldn’t stop discussing: the active intellect.

Aristotle had said that the human mind has two parts: a “potential intellect” (which can receive ideas) and an “active intellect” (which makes ideas intelligible, like a light that illuminates things). But Aristotle wasn’t clear about whether the active intellect was inside each person or separate from them.

Arabic philosophers, especially Avicenna and Averroes, said it was separate—a single cosmic intelligence that shines down on all human minds. The active intellect is like the sun: it illuminates ideas, and our minds just receive the light. When you understand something deeply, you’re “conjoined” with the active intellect.

This was a radical idea. It meant that the deepest knowledge isn’t really yours—it’s something you tap into. Some European philosophers, like Albertus Magnus (who lived around 1200–1280), were attracted to this. He talked about the “acquired intellect” (intellectus adeptus), a state where a person becomes so perfectly connected to the active intellect that they no longer need their senses. They just know.

Thomas Aquinas disagreed sharply. He thought this was impossible. Human knowledge always starts with the senses, he argued, and we never outgrow that. We can’t dispense with images and experiences. Perfect knowledge of everything isn’t possible in this life.

Again, this debate—about whether knowledge comes from outside us or is built from our own experience—never really ended.

What Happened Next

After about 1300, Europeans stopped translating Arabic philosophy. New Greek-to-Latin translations became available, and Arabic sources were no longer as necessary. But the ideas had already taken root. For the next 300 years, European philosophers kept arguing about Avicenna’s essence-existence distinction, Averroes’s one-intellect theory, and the active intellect.

The Arabic philosophers had become part of the furniture of European thought. You couldn’t study philosophy at a medieval university without reading Averroes’s commentaries. Even when people disagreed with him, they had to engage with him.

And some Arabic ideas—like Avicenna’s “Flying Man” or Averroes’s arguments about the eternity of the world—are still discussed in philosophy classrooms today.

Key Terms

Term	What it does in the debate
Active intellect	A separate cosmic intelligence that “illuminates” ideas for human minds to grasp
Acquired intellect	The highest state of understanding, when a person’s mind is fully connected to the active intellect
Estimation	An internal sense that perceives meanings (like danger or friendliness) directly
Essence	What a thing is, its definition or nature
Existence	The fact that a thing is, its reality
Intention	A perceived meaning or concept, not just raw sensory data
Unicity thesis	The claim that there is only one intellect shared by all human beings

Key People

Avicenna (Ibn Sina) — A Persian philosopher and doctor (980–1037) who wrote massive encyclopedias of philosophy and medicine; he introduced the essence-existence distinction, the Flying Man thought experiment, and the theory of internal senses.
Averroes (Ibn Rushd) — An Andalusian philosopher (1126–1198) who wrote detailed commentaries on Aristotle; he argued for the unicity thesis (one intellect for everyone) and became known as “the Commentator” in Europe.
Thomas Aquinas — A Christian philosopher and theologian (1225–1274) who engaged deeply with Arabic sources; he rejected both the one-intellect theory and the idea that we can know everything without senses.
Albertus Magnus — A German philosopher and bishop (c. 1200–1280) who was more sympathetic to Arabic ideas, especially the acquired intellect and the theory that forms come from a separate source.

Things to Think About

The Flying Man: Avicenna thought you’d know you exist even without any senses. Do you agree? Could there be a self without any awareness of a body? What would that self be like?
One mind for everyone: Imagine that all humans share one intellect. What would that mean for personal identity? Would you still be “you”? Would it change how you think about learning and knowledge?
Eternal world: If God is perfect and unchanging, does it make more sense to say the world was created at a specific time, or that it has always existed? Can you think of arguments for both sides?
Essence vs. existence: Is there a difference between “what something is” and “that it is”? Can you imagine something’s essence fully without knowing whether it exists? Does that mean existence is somehow extra?

Where This Shows Up

In video games and sci-fi: Questions about shared consciousness (the Borg in Star Trek, the Geth in Mass Effect) echo Averroes’s one-intellect theory.
In psychology and neuroscience: The debate about whether animals think, judge, or just react to stimuli is a modern version of the debate about estimation.
In philosophy of mind: The question of whether consciousness is private to each person or somehow shared is still very much alive.
In historiography: The story of how ideas travel between cultures—and how they get transformed in translation—is a fascinating lens for understanding how knowledge develops.