Commentary on Ammonius: Keeping Philosophy Alive in a Dangerous Time

Imagine you’re a student in Alexandria, Egypt, around the year 485. You’re sitting in a classroom, and your teacher—a famous philosopher named Ammonius—is explaining Aristotle. But here’s the strange thing: outside your classroom, the city is mostly Christian, and the emperor has just ordered harsh measures against people who still worship the old Greek gods. Some of your classmates are Christians. Some are pagans who still believe in the old gods. Some aren’t sure what they believe. And your teacher, Ammonius, is a pagan—someone who doesn’t believe in the Christian God.

How does philosophy survive in a world where your ideas could get you killed? That’s the puzzle at the heart of Ammonius’ story.

A Teacher in a Crossfire

Ammonius lived in Alexandria, which in the late 400s CE was both a center of learning and a powder keg. Christians had been in power for over a century, and tensions between Christians and pagans sometimes exploded into violence. In 415, a philosopher named Hypatia had been dragged from her chariot and killed by a Christian mob—just because she was a famous pagan teacher. So when Ammonius started teaching, he was walking a dangerous line.

We know about Ammonius mostly from people who hated him. A philosopher named Damascius wrote a history that called Ammonius “wickedly greedy” and accused him of making a secret deal with the Christian bishop to keep his school open. The accusation was that Ammonius agreed to stop teaching certain things—maybe to stop talking about the old religious rituals (called “theurgy”) that Neoplatonist philosophers believed could connect you to the gods. Or maybe he agreed not to teach Plato’s dangerous ideas, only Aristotle’s safer ones. Or maybe he even betrayed his fellow pagans to the authorities.

Nobody really knows what deal Ammonius made, or if he made one at all. Damascius was not a neutral observer—he was a passionate believer in the old gods and the magical rituals, and he may have been angry that Ammonius survived while other pagans suffered. What we do know is that Ammonius kept teaching. His school stayed open. His students kept learning. And through his work, the philosophy of Aristotle and Plato survived into the Middle Ages and eventually reached us.

The Great Harmonizer

Ammonius did something clever. For centuries before him, philosophers had argued about whether Plato and Aristotle agreed with each other. Plato talked about eternal, perfect “Forms” that exist beyond our world. Aristotle seemed to criticize those Forms. Plato’s God was a creator who made the world on purpose. Aristotle’s God just thought about thinking and didn’t seem to care about the world at all. How could you be a follower of both?

Most earlier philosophers picked a side. Ammonius tried something different: he argued that Plato and Aristotle were really saying the same thing, just in different ways. When Aristotle seemed to criticize Plato’s Forms, Ammonius said that Aristotle actually agreed with them—he just expressed himself differently. When Aristotle’s God seemed distant and uncaring, Ammonius wrote a whole book arguing that Aristotle’s God was actually both the final cause (the goal that everything aims at) AND the efficient cause (the maker who creates everything). This made Aristotle’s God look a lot more like Plato’s creator.

This might sound like cheating. But think about what Ammonius was really doing. If you’re a pagan philosopher in a Christian city, you need your philosophy to be both big enough to hold different views and safe enough to teach. Showing that the two greatest Greek philosophers agreed with each other made philosophy seem like a unified, reasonable project—not a bunch of warring sects fighting about gods.

The Sea-Battle Puzzle

One of Ammonius’ most interesting ideas came from his commentary on Aristotle’s On Interpretation, specifically chapter 9—the famous “sea-battle” argument. Here’s the puzzle:

Suppose I say, “There will be a sea battle tomorrow.” Is that sentence true or false right now? If it’s true now, then the battle has to happen—it’s already determined. If it’s false now, then it can’t happen. Either way, the future seems fixed. But we feel like the future is open—like we have choices, and things could go one way or another.

Aristotle thought that sentences about future contingent events (things that might happen or might not) don’t work the same way as sentences about the past or present. But philosophers argued for centuries about exactly what he meant.

Ammonius added two more determinist arguments to Aristotle’s discussion. One was called the “Reaper” argument: if you’re going to reap your crop tomorrow, then it’s not the case that you might reap and might not—you definitely will reap. But if you’re not going to reap, you definitely won’t. And either you will reap or you won’t. So where’s the “maybe”?

Ammonius also worried about God’s knowledge. If God knows everything for sure, including what you’ll do tomorrow, then isn’t your future already fixed? Even if you don’t know what you’ll do, God does—so it’s already decided.

Ammonius’ answer is subtle. He said that future contingent statements are “true in an indefinite manner” but not “true in a definite manner.” What does that mean? It’s a bit like knowing that one of two things will happen, but not knowing which. “Either there will be a sea battle tomorrow or there won’t” is definitely true—but neither option is definitely true on its own. And as for God’s knowledge, Ammonius argued that God is outside time. For God, there is no “future”—everything is present. So God can know things definitely, but that doesn’t make them determined in our time-bound world.

This part gets complicated, but here’s what it accomplishes: Ammonius tried to save room for human freedom and chance in a world where it seemed like everything might be fixed by logic or by God. His solution isn’t fully satisfying—philosophers still argue about it—but it showed real creativity in wrestling with a genuinely hard problem.

Why This Matters Now

You might wonder: why should we care about a philosopher from 1,500 years ago whose main job was explaining other philosophers?

Here’s one reason: Ammonius and his students saved Aristotle. Most of what we know about Aristotle’s logic, physics, and metaphysics comes through the commentaries of Ammonius and his followers. When Arabic philosophers like Al-Farabi and Avicenna studied Aristotle, they used works from Ammonius’ school. When Thomas Aquinas read Aristotle in medieval Europe, he used a translation of Ammonius’ commentary on On Interpretation.

But there’s another reason. Ammonius faced a question that philosophers still face today: how do you keep thinking freely when the world around you wants conformity? He lived in a city where teaching the wrong ideas could get you killed. He may have made compromises. He may have hidden parts of what he believed. He definitely made enemies who called him greedy and treacherous.

But he also kept teaching. He trained a generation of students who passed philosophy on to the next generation, and the next, all the way down to us. Sometimes survival is a form of courage. Sometimes the most important thing a philosopher can do is just stay in the classroom, keep the conversation going, and trust that the truth will outlast the people who want to suppress it.

Key Terms

Term	What it does in the debate
Determinism	The idea that everything that happens is fixed in advance, leaving no room for chance or free choice
Contingent	Describes things that could be one way or another—they’re not necessary, not impossible
Theurgy	Religious rituals that Neoplatonists believed could connect humans to the gods
Efficient cause	The thing that makes something happen or brings something into existence
Final cause	The goal or purpose something aims at
Bivalence	The principle that every statement is either true or false

Key People

Ammonius (c. 435–520 CE): A pagan philosopher in Alexandria who ran a school teaching Aristotle and Plato, possibly making a deal with Christian authorities to keep his school open
Damascius (c. 460–after 538): A pagan philosopher who hated Ammonius and accused him of betraying fellow pagans out of greed
Hypatia (c. 355–415): A famous woman philosopher in Alexandria who was killed by a Christian mob, showing how dangerous the city could be for pagan teachers
Proclus (412–485): The head of the Platonic Academy in Athens, who taught Ammonius and had a huge influence on his thinking

Things to Think About

If you were a philosopher in a society that punished some ideas, would you compromise to keep teaching, or would you speak out and risk everything? Is there a point where compromise becomes betrayal?
The sea-battle argument asks whether the future is already fixed. Do you think humans have genuine free will, or is everything determined by causes we can’t control? How would you know which is true?
Ammonius argued that Plato and Aristotle really agreed with each other. Is finding harmony between different thinkers always a good thing? Can you ever force agreement where there isn’t any?
Most of what we know about Ammonius comes from people who hated him. How do you figure out the truth about someone when your sources are biased?

Where This Shows Up

The problem of free will still haunts debates about neuroscience, criminal justice, and whether people “deserve” punishment
How to survive as a minority in a society where your beliefs are unpopular is a question faced by religious minorities, political dissidents, and whistleblowers today
The “harmony” approach lives on in modern philosophy, where thinkers try to reconcile science and religion, or different philosophical traditions
The sea-battle argument connects directly to modern discussions about time travel, alternate universes, and whether the future is “already there” waiting for us