Why is there something rather than nothing?

What can physics say, and where does it stop?

Physics can say a great deal about how our universe changed over time. NASA’s overview describes a brief burst of stretching called cosmic inflation about 13.8 billion years ago. When it stopped, its energy turned into matter and light: the hot Big Bang. About 380,000 years later, the universe cooled enough to let light travel freely. That glow is still detectable today. For the very early steps, see our story What Happened in the First Second After the Big Bang?

Before inflation, the trail goes cold. NASA says plainly that scientists aren’t sure what came before inflation or what powered it. Even NASA’s Ask an Astrophysicist team, answering a reader, said it would not describe the Big Bang’s hydrogen as coming from “nothing.” It came from a hot, dense state full of energy.

Some physicists have tried to go further back. In 1982, the physicist Alexander Vilenkin published a model in which a universe is created by quantum tunneling “from literally nothing.” In his 2012 book A Universe from Nothing, the cosmologist Lawrence Krauss argued that the laws of quantum physics can explain why there is something rather than nothing. The Stanford Encyclopedia of Philosophy notes that Frank Wilczek, and Stephen Hawking with Leonard Mlodinow, have made similar claims.

These ideas are real physics, and they are interesting. But what do they mean by “nothing”? In quantum physics, the vacuum, or empty space, is not empty. As the Stanford Encyclopedia puts it, vacuums have energy, and energy can turn into mass. So a quantum vacuum is still something. The philosopher David Albert, author of a book on quantum mechanics, made this point in a well-known 2012 review of Krauss’s book in The New York Times. A vacuum, he wrote, is a particular arrangement of quantum fields. Particles popping out of it are no more a creation from nothing than a fist appearing when you close your fingers. Albert also asked where the laws of quantum physics came from. He noted that Krauss admits, near the end of the book, that he takes those basic laws for granted.

Krauss has a reply, and it deserves a fair hearing. As the Stanford Encyclopedia reports, he argues that science often makes progress by giving old words sharper meanings. On his view, swapping an unclear question for one physics can study is an improvement, not a trick. Critics answer that it is a different question. Either way, the physics answers describe how one state of the world can turn into another. They do not explain why there is a world, or laws, at all.

What do answers with God, and without God, say?

The cosmological argument. This is the classic answer from faith, and it has a long history. The Stanford Encyclopedia traces it through philosophers of the Islamic world such as Ibn Sina (about 980–1037), the Christian thinker Thomas Aquinas, and Leibniz. One version starts from the fact that the things around us might not have existed. They are contingent, meaning they depend on something else. Leibniz argued that the reason for the whole chain of such things must lie outside the chain, in a being that must exist. That being, he wrote, is what we call God.

A second version, the kalām argument, comes from Muslim theologians such as al-Ghazali (1058–1111). It says that whatever begins to exist has a cause, and the universe began to exist, so it has a cause. Today the philosopher William Lane Craig defends it. He argues that something cannot come out of nothing.

The brute-fact view. Many other thinkers answer that the universe needs no reason beyond itself. A brute fact is a fact with no further explanation. The philosopher Bertrand Russell said in 1948 that the universe is “just there, and that’s all.” The Stanford Encyclopedia notes that Stephen Hawking later said much the same.

Other views. Some philosophers think something was always the likely outcome. The philosopher Peter van Inwagen argued that there are endless ways for there to be something, and at most one way for there to be nothing. So the chance of nothing is zero, even though nothing is not strictly impossible. Others, like Ludwig Wittgenstein, saw the question less as a puzzle and more as an expression of awe that the world exists at all.

What is the strongest objection to each answer?

To the physics answers: they start with laws and fields. As Albert argued, that leaves the deepest question untouched.

To the God answers: David Hume and Immanuel Kant attacked the cosmological argument in the 1700s. Critics also ask a simple question. If God can exist with no cause, why can’t the universe? The Stanford Encyclopedia reports that some philosophers, such as Bede Rundle, argue exactly that. Defenders reply that the argument never said everything needs a cause. Only things that might not have existed need one, and God, on their view, is not that kind of thing. Critics of the kalām argument, such as Wes Morriston, say its first step is not as clear as it looks.

To the brute-fact view: it seems to give up on explaining. Leibniz’s principle of sufficient reason, the idea that everything has a reason, lies behind the God answer. The Stanford Encyclopedia calls it both powerful and controversial. If you accept it, a brute fact looks like a gap. If you reject it, the God answer loses its main support.

There is a trap under all of this. The Stanford Encyclopedia points out that we usually explain one thing by pointing to another thing. That cannot work here. If you say something exists because a designer wanted it, you have already assumed the designer. For this reason, some philosophers think the question cannot be answered at all.

What do people often get wrong?

“Science has shown the universe came from nothing.” The physics models start with quantum laws and fields. As shown above, that is not nothing in the full sense.

“The Big Bang explains where everything came from.” The Big Bang theory describes how the early universe grew and cooled. NASA says scientists are not sure what came before inflation.

“Only religious people ask this.” Philosophers of every kind take it seriously. The Stanford Encyclopedia calls it, so far, a live question.

“The God answer falls apart at ‘who made God?’” Defenders say the argument applies only to things that might not have existed. You may or may not find that convincing, but it is a real reply.

Where can people of faith and skeptics agree?

• The science is shared. Believers and nonbelievers read the same evidence about the Big Bang. Neither side needs to fear it.
• Physics has limits here. Even Krauss admits his account takes the basic laws of quantum physics for granted, so where those laws come from is still an open puzzle for everyone.
• Humility fits. The philosopher William James, quoted in the Stanford Encyclopedia, called the question of being the darkest in all philosophy. He wrote that all of us are beggars here, and no school can look down on another.
• Wonder is common ground. Whether you see a Creator, a brute fact, or an open mystery, the fact that anything exists can stop you in your tracks.

How can you check this yourself?

• Ask what “nothing” means. When a video or book says the universe came from nothing, check whether that “nothing” has laws, fields, energy or space in it.
• Read the Stanford Encyclopedia. Its entries on Nothingness and the Cosmological Argument are free and lay out both sides.
• Read Leibniz himself. His short 1714 essay Principles of Nature and Grace asks the question in section 7. A free modern English version is on Early Modern Texts.
• Read both sides of the Krauss debate. Read Albert’s review, then look for Krauss’s replies, and judge whether they are answering the same question.

The answer stays the same after all this detail. Physics can trace the universe a long way back, but it always starts with something. Why there is anything at all remains beyond science, and it is a question people of every belief can ask together. For more on how the two fit, read Science and Faith: Enemies, Strangers, or Partners?