… In chapter 8, when I talked about the “growth” of the Abrahamic god, it wasn’t because I feel confident that this god, or any god, exists (a question I’m unqualified to answer). It was because the god of the Abrahamic scriptures—real or not—does have a tendency to grow morally. This growth, though at times cryptic and superficially haphazard, is the “revelation” of the moral order underlying history: as the scope of social organization grows, God tends to eventually catch up, drawing a larger expanse of humanity under his protection, or at least a larger expanse of humanity under his toleration.

So when the tribes of Israel coalesced into a single polity, Yahweh expanded to encompass them all, reflecting a kind of moral advance—mutual acceptance among those tribes, the acceptance that allowed the Israelite nation to form. And after the exile, when Israel gained a secure place in the multinational Persian Empire, the fierce nationalism of an earlier Israel abated. Now Hebrew scriptures emphasized kinship with other nations of the empire and downplayed past enmities.

The Christian God, like the God of Israel, drew moral nourishment from the multinational nature of empire, in this case the Roman Empire. Salvation was granted to all believers without regard for nationality. Vestiges of a narrower god—the god reflected in Jesus’s calling a woman a “dog” because she wasn’t from Israel—were left behind.

Islam’s formation, in a sense, telescoped a millennium or so of God’s Judeo-Christian history. First, Allah transcended tribal distinctions, as he had done under the name Yahweh in ancient Israel. Then Islam, toward the end of its formative period, acquired the multinational perspective of empire, admitting, like Christianity (and like modern Judaism), people of all nations to the community of belief. But Islam went further than the Christianity of the Roman Empire; in places its scripture granted the possibility of salvation to people outside the fold—to Christians and Jews and even to Zoroastrians, who fell within the realm of empire upon Islam’s conquest of Persia.

Of course, this progressive-sounding list of theological milestones was selected with a bias. I could just as easily have listed the downsides of imperial affiliation—the doctrine of jihad, a product of early imperial Islam, or the Christian doctrine of holy war, both of which smoothed slaughter during the Crusades. Throughout human history, as zones of non-zero-sumness have expanded, and with them the extent of polities and religions, amity within the zones has often been matched by enmity between them. The movement toward moral truth, though regionally significant, has been globally modest, at best.

Now we’ve reached a stage in history where the movement toward moral truth has to become globally momentous. Technology has made the planet too small, too finely interdependent, for enmity between large blocs to be in their enduring interest. The negative-sum side of the world’s non-zero-sumness is too explosively big to be compatible with social salvation. In particular: in any envisioned “clash of civilizations” between Islam and the West, neither side can realistically hope for conquest.

So if the God of the Abrahamic faiths is to keep doing what he has often managed to do before—evolve in a way that fosters positive-sum outcomes of non-zero-sum games—he has some growing to do. His character has to develop in a way that permits, for starters, Muslims, Christians, and Jews to get along as globalization keeps pushing them closer together.

If the modern world offers cause for pessimism on this front, at least cause for optimism can be found in the ancient world. As we saw in chapter 8, the closest thing in that world to globalization were periods of incipient empire, when nations were thrown together in new combinations and new avenues of contact were opened. And, as we’ve just seen, the God of all three faiths passed the imperial test in the ancient world; when put in the multinational context of empire, he summoned enough broad-mindedness to facilitate the playing of non-zero-sum games. God’s character may not seem to be growing at the moment, but he has it in him.

Of course, God’s character is a product of the way Muslims, Christians, and Jews think of him. So to say the Abrahamic god must grow means they must start thinking of him in a slightly different way—as a god who is less inclined to play favorites among them. In other words, they need to start thinking of themselves as a bit less special.…