Beginning in the thirteenth century, the three monotheistic religions parted ways, with the Jewish and Christian world going in one direction and the Islamic world going in another. We are still coming to terms with that split.

But the three faiths still hold more in common than we typically recognize today. For example, Islam (like Judaism and Christianity) has a powerful sense of the transcendence of God”His majesty, His greatness, His incomparability with anything else. You see this in the Muslim’s abject bow at prayer, head lowered to the ground.

There is a sentence in the Psalms that says that the whole world, the whole vastness of the stars and everything else, is to God but a grain of sand. The whole world is insignificant. That’s a way of saying how great God is. The purest single note in Islam is this greatness of God, and the appropriate human response to it is “yes.” “Islam” means submission: “Yes.”

T. S. Eliot says that the most beautiful single line in all of human poetry is in Dante: E ‘n la sua volontade è nostra pace . “In His will, our peace.” That’s a Christian and a Jewish expression of the relationship of humans to God. It sounds like submission, doesn’t it? “In His will, our peace.” Sometimes we are told that Islam means “peace.” It does mean peace, if you submit to His will. And it sounds as though that’s very similar to the Jewish and Christian “In His will, our peace.” Mutual understanding can begin from there.

Difficulties in understanding arose in part because Muslim scholars interpreted Plato and Aristotle in such a way that they became convinced that God’s greatness and transcendence is so superior to us that God couldn’t be bothered with this grain of sand, with this changeable world in which there are seasons, upheavals and erosions, historic transformations and individual contingencies. God is concerned with necessary things, the things that are eternal, the things that stay the same. His will is not affected by all the things that happen on our level of existence.

Focusing on God’s transcendence is Islam’s great strength. Its weakness is that it can say little about human liberty, and about how human choice affects the will of God. How can God allow for human freedom? How can God permit human choice? It’s as though medieval Muslims imagined liberty to be a zero-sum game. If humans have it, God doesn’t. If God has it, humans don’t. It’s a philosophical problem they couldn’t resolve.

Jewish, Christian, and Muslim writings thus divided, first of all, over the role of liberty in the relations between God and man. So great is God that in the Islamic view He overpowers human liberty. This suggests a kind of determinism. What God knows and does is eternal and necessary and can’t be changed, and no individual will, no knowledge of singulars or contingency, is possible to God. He doesn’t concern himself with things like us, and you can’t talk about human beings as images of God.

“Man and woman He created them,” that much is clear in Genesis. “In the image of God He created them.” For Jews and Christians, human beings are made in the image of God. For Islam, to conceive of an image of God is to fall very short of, even to falsify, His greatness. To speak of images of God is blasphemy. It marks one as an infidel”one who has not seen the point, and is in denial about the inconceivable greatness of God.

The second cause of separation flowed from the first: the tendency toward a doctrine of double truth. God is light, unchanging, eternal. Muslim scholars couldn’t discern a way, philosophically, to deal with contingency and changeable things, such as human beings changing their minds and following their own vocations. And so they had one set of truths to which philosophy led them, and another for talking about reward and punishment as the Koran does. The Koran seems to talk about the ethical life, and it allows for a certain degree of human liberty. But Muslims described that truth as “allegory””that is, something other than philosophical truth. Their way of solving the problem was thus not to solve it, but rather to say it’s insoluble. Christians and Jews, by contrast, adopted a different solution. If “x” happens, then God eternally willed it. God knows necessary things necessarily and contingent things contingently.

The third difference between Judaism and Christianity on the one hand and Islam on the other had to do with what theologians call the unicity of intellect. Islamic thinkers thought they were following Aristotle, but they were not. With Aristotle, they had come to believe that each of us has two kinds of intellect. One is the “potential” intellect, by which we are open to understand all things. We receive impressions of the world, we take things in. But then there is an active, questioning, almost aggressive intellect, which goes out raising questions, deploying logic, calculation, and abstraction. This drive was then called the “active intellect.”

Some Islamic scholars took the view that while we each have a potential intellect”we are all receivers”there is really only one potential intellect in the world: the Divine intellect. They reasoned that when, as a fruit of inquiry or investigation, we have an insight, we come to share in an understanding that others have shared before.

One difficulty with this interpretation is purely epistemological. If there is only one potential intellect for all, then it alone possesses all knowledge, and individuals would not have to discover knowledge for themselves. This is completely contrary to experience. Another difficulty is that this way of analyzing the act of understanding diminishes human liberty. It deprives human beings of their own personal acts of understanding. We are no longer creatures capable of individual insight and choice, the kind of creatures that the stories of Judaism and Christianity require.

Every story in the Bible is a story of how human beings use their will. Sometimes they say “yes” to God, sometimes “no.” King David in one chapter is faithful to his Lord, and in the next he is not. The suspense is always, “What will he do next?” And so the axis of every story in the Bible is the arena of human will. It is the most important theater of action in the world. In this arena, God offers human beings friendship: Will they accept it or not? That’s the drama of history. That drama hinges on human liberty, our capacity to say “yes” or “no.” The Jewish and Christian story is that God created the whole cosmos so that somewhere in it would be a creature with whom He could share His love or His friendship. And to human beings He offered His friendship, as to no other creature. That’s why human beings have a dignity beyond any other creature. That’s why the death of a cockroach or a fly presents no moral crisis”no wrong against the natural order, in which all things come to be and then perish. Yet the untoward death of humans is somehow a violation of the order of things.

God wants the friendship of free people, not slaves; we must be free to say “yes.” “The light shines in the darkness, and the darkness has not overcome it,” begins the Gospel of John. So freedom is at the heart of the Jewish and Christian story in a way that it is not at the heart of the Islamic story.

The Jewish and Christian story also unleashes human dynamism. In the eleventh century, the shoulder harness for horses and oxen was invented in the West. There was also the invention of the rear rudder for steering ships and the invention of mariners’ tools for plotting one’s position on the earth, which enabled men to go out on the ocean. There was the invention of eyeglasses and of magnifying glasses, as well as cogs and wheels that make watches and clocks possible. There was a sudden explosion of innovations”what’s called the first Industrial Revolution of the eleventh century”that starts making Western civilization the equal of Islam.

The fact that the people of the West believed that all humans are made in the image of God meant that they understood themselves to be called to create, to invent, to discover, to figure out how all things work. And the result was the great thrust of modern science, modern technology, the invention of a new form of political science, the process of “modernization,” and the invention of economics. Jews and Christians took joy in discovery. For them, work was a vocation; it was to be, in some sense, God-like.

In light of this history, how should Christians of good will respond to Islam today? The United States is now home for a great many Muslims. They are our fellow citizens. All of us have been thrown into a worldwide struggle for our own survival against terrorists. That’s a fresh reason”but not the only reason”why it’s our task to see if there are resources shared by Islam, Judaism, and Christianity that can help us to revisit those three ancient problems”the transcendence of God, human liberty, and truth.

Above all, we must speak for the rights of women in Islam and the poor within Islamic countries. We must help create the conditions for economic prosperity, democracy, and human rights in the Islamic world. When we speak of human rights, we cannot mean only American rights. We mean the rights of all humans, including the rights of Muslims.

We need to give voice to those rights. We would be unfaithful to ourselves if we did not. We should listen for echoes of this voice in the Islamic world. We saw the joy in Afghanistan when people were liberated from the Taliban. We see in Iran today young people taking to the streets in the name of freedom.

There is a widespread desire everywhere to have human rights declared, protected, and advanced. The world we should work for in the decades just ahead is a world in which Muslims, like every other people on this planet, are free to worship as conscience directs them; a world in which Muslims, like every other people, are free to inquire and study and write and speak; a world in which Muslims, like every other people, escape from poverty by the millions, and find abundant opportunity to employ their immense wealth of God-given talents to make a better Earth; a world in which Muslims, along with all other peoples, are free to practice the arts of democracy, civility, and all the fundamental human rights that are endowed in every man and every woman on this earth by our Creator, Who is One, and Who is Great. May His name be praised, in, by, and through liberty for all.

Michael Novak is a Senior Fellow at the American Enterprise Institute. A longer version of this essay was given at a conference called “Truth and Freedom: Toward a Common Understanding Among Muslims, Jews, and Christians,” sponsored by the Becket Fund for Religious Liberty.