麻豆传媒

HERE鈥橲 the dilemma: if the universe began with a quantum particle blipping into existence, inflating godlessly into space-time and a whole zoo of materials, then why is it so well suited for life?

For medieval philosophers, the purported perfection of the universe was the key to proving the existence of God. The universe is so fit for intelligent life that it must be the product of a powerful, benevolent external deity. Or, as popular theology might put it today: all this can鈥檛 be an accident.

Modern physics has also wrestled with this 鈥渇ine-tuning problem鈥�, and supplies its own answer. If only one universe exists, then it is strange to find it so hospitable to life, when nearly any other value for the gravitational or cosmological constants would have produced nothing at all. But if there is a 鈥渕ultiverse鈥� of many universes, all with different constants, the problem vanishes: we鈥檙e here because we happen to be in one of the universes that works.

No miracles, no plan, no creator. As the cosmologist Bernard Carr puts it: 鈥淚f you don鈥檛 want God, you鈥檇 better have a multiverse鈥�. But is that really our only choice? Is there another way to think about divinity?

In Western philosophy, the theory of infinite worlds dates back 2500 years to the 鈥渁tomists鈥� of ancient Greece. For philosophers like Leucippus, Democritus and Epicurus, the universe was composed of microscopic, indivisible bits of matter, or atoms. These atoms moved eternally in a void, colliding haphazardly with one another until they formed a vortex.

In this vortex, the heavy elements clustered together to form earth, light elements scattered far from the centre as fire, and mid-weight particles formed water and air in between them. Crucially, this void was spatially infinite. So particles elsewhere were forming vortices to create other worlds, even an infinite number of them. When these worlds died, their atoms would go on to form new worlds elsewhere.

Some of these worlds were small, some large, some lifeless, and some just like ours. But all of them were the result of random collisions in infinite space, no God required. For the atomists, 鈥済ods鈥� were enlightened sages engaged in blissed-out contemplation. They existed, but did not create, sustain or intervene in our world 鈥� they were, in a word, irrelevant.

鈥淚f you don鈥檛 want God, you鈥檇 better have a multiverse. Is that the only option?鈥�

If the atomists gave us a spatial model of the multiverse, their Stoic rivals gave us a temporal one. For the Stoics, matter is continuous. There are no atoms, no void and nothing beyond our cosmos that might form other worlds. In short, ours is the only world in the universe.

More precisely, ours is the only world at this moment. For the Stoics, the cosmos will eventually end when the sun dries up Earth and consumes it in flames, only for it to be born again. The periodic destruction and regeneration of the universe is the stand-out feature of early Stoic cosmology, a process called ekpyrosis (鈥渙ut of fire鈥�).

If the atomists pushed their gods out of the cosmos, the early Stoics pulled them all the way in. The Stoic god was the animating force of the cosmos itself: creating, sustaining, unravelling, and regenerating all things. If the atomists were effectively non-theists, then the Stoics were effectively pantheists: the world itself was what they meant by 鈥済od鈥�.

Atomist day camps

Two rival ancient multiverses, then: one spatial and one temporal, one non-theist and one pantheist, one haphazard and one deterministic, but both of them dead-set against the conventional idea of 鈥淕od鈥�. So as thrilling or threatening as the multiverse seems today, it wouldn鈥檛 be nearly so daunting if we鈥檇 spent our childhoods modelling alternative worlds in atomist day-camps, or contemplating the eternal return of the cosmos in Stoic temples.

But of course, we didn鈥檛. Both traditions lost out to a very different conception of God: an unchanging intelligence just like us, but without our frailties, an all-powerful Father, presiding over a singular cosmos. How did this happen?

Plato insisted on a creator-god who made only one universe: 鈥淎re we right then to speak of one universe, or would it be more correct to speak of a plurality or infinity? ONE is right鈥� our universe was and is and will continue to be [the god鈥檚] only creation.鈥�

Aristotle had a different argument, but also favoured a singular cosmos. This double whammy from two of the most venerated thinkers of all time meant that when the early Christians came along, the atomists had been dismissed as hedonists, idiots, and degenerates. Saint Augustine, whose thinking shaped Western Christianity, didn鈥檛 even bother to refute the atomists鈥� arguments in his masterwork The City of God, completed in 426 AD.

The Stoics, on the other hand, nearly drove Augustine mad. If, as the Stoics suggested, the universe is both cyclical and perfect, every world is exactly the same as the one before it. For Augustine, this meant that souls would be created, fallen, converted or not, saved or not, and then just when they reached heaven or hell鈥� back on the cosmic carousel to live the same life. Augustine hated this idea, and railed against it with uncharacteristic vigour: 鈥淕od forbid that what [they] threaten should be true!鈥�

Fortunately, Augustine found solace in the Bible. 鈥淐hrist died once for all for our sins鈥� (Romans 6:9). This happened once, notes Augustine: so this must mean there are no other worlds before or after ours. Can you imagine Jesus being sent to live and teach and die in an infinite number of worlds? There could only be one Christ, like the God he incarnates. Therefore there is only one world. Phew.

For all their differences, then, both the atomists and the Stoics fell victim to the sovereign deity of power and might. Pre-modern cosmology effectively leads to the opposite of its modern counterpart: 鈥淚f you don鈥檛 want a multiverse, you鈥檇 better have God.鈥�

Is there any less antagonistic way to think about God and the multiverse? I think there is, and to explore it I鈥檇 like to introduce two final dramatis personae: Nicholas of Cusa, and Giordano Bruno, the ex-Dominican polymath now lauded as the father of secular science. Their visions of the universe were nearly identical 鈥� but with one tiny difference that brought them very different fates.

The standard history of science tells us that the Ptolemaic vision of the cosmos, with Earth at the centre of a succession of celestial spheres, was unrivalled until the mid-16th century, when Copernicus put the sun at its centre. A hundred years before Copernicus, however, Cusa had ventured a far more radical proposal: the universe, he said, had no centre.

Everything is in motion all the time, Cusa suggested, and so 鈥渋t always appears to every observer, whether on the earth, the sun, or another star, that one is鈥� at an immovable centre of things and that all else is being moved.鈥� If everything is moving, then there鈥檚 no particular centre. Start from any cosmic body, Cusa suggested, and the visible area around it is what we call a world.

This starts to sound a lot like the modern version of the multiverse: our 鈥渦niverse鈥� is just the visible portion of a much greater cosmos. Like the multiverse, Cusa鈥檚 universe is spatially boundless, having nothing outside itself that might bind it. But unlike modern theorists, Cusa refused to call the cosmos 鈥渋nfinite鈥� because it is dependent on its creator. In Cusa鈥檚 terminology, God alone is 鈥渁bsolutely infinite鈥� whereas creation is a 鈥渃ontracted infinity鈥�.

This distinction aside, Cusa is getting close to Stoic heresy, with a universe that looks much like God. Like God, the Cusan universe has no limits. Like God, the universe contains everything that is, as well as the seeds of what will be. As Cusa puts it, 鈥淚t is as if the Creator had spoken, 鈥楲et it be made,鈥� and because God, who is eternity itself, could not be made, that was made鈥� which would be as much like God as possible.鈥�

Traditionally, Christian doctrine has taught that humans are made in the image of God. Cusa disrupted this idea by saying that the universe, not man, bears the image of God. And if humans are not particularly godlike, then God is not particularly humanoid. God doesn鈥檛 look like a patriarch in the sky: he looks like the universe.

Unsurprisingly, Cusa got into a bit of trouble with church authorities for this, the fear of which caused him to tag a whole 鈥淐hrist section鈥� onto the end of his cosmology. But he got away with it 鈥� he even became a cardinal. Giordano Bruno was not so fortunate: he said more or less the same thing a century and a half later, and he was put to death by the Inquisition. Bruno had the misfortune to come along in the wake of the Reformation and Copernicus鈥檚 contention that Earth was not the centre of the cosmos. One might say the Roman Catholic Church was a little on edge.

But the largest factor leading to Bruno鈥檚 demise was a tiny tweak he made to Cusa鈥檚 cosmology. For Bruno, the universe is not contractedly infinite, it is genuinely infinite 鈥� both in power and extent. For Bruno, the universe must be infinite because its creator is.

But if the universe is infinite, there is no bit of God left over before or beyond or outside creation. In the course of his trial, Bruno made some half-hearted efforts to say that the universe was in some sense different from God, and that Christ was more special than anyone else, but the Inquisition wasn鈥檛 fooled. What he really meant was that this infinite universe is the source of all things, the life in all things, and the end of all things 鈥� or what everybody means by God. This is, in short, pantheism. Not Stoic pantheism, with its infinite cycles of rebirth, but it鈥檚 no less threatening to the theological order.

In fact, such pantheisms are even more theologically threatening than atheism, precisely because they change what it means to be God. Not an anthropic creator beyond the world, but the force of creation within it.

So we don鈥檛 need to choose between God and the multiverse. Rather, we might rethink what it is we mean by those old godly terms like creation, power, renewal and care. Is it possible that modern cosmology is asking us, not to abandon religion, but to think differently about what it is that gives life, what it is that鈥檚 sacred, where it is we come from 鈥� and where we鈥檒l go?

This article appeared in print under the headline 鈥淕od vs the multiverse鈥�

Explore more with our multi-part feature: 鈥�Human universe鈥�