“Every formula which expresses a law of nature is a hymn of praise to God,” the trailblazing astronomer and leading Figuring figure Maria Mitchell wrote in the second half of the nineteenth century as she contemplated science, spirituality, and the human hunger for truth. Every great scientist in the century and a half since has been faced with this question, be it by personal restlessness or public demand. Einstein addressed it in answering a little girl’s question about whether scientists pray. Quantum theory originator Max Planck believed that “science cannot solve the ultimate mystery of nature [because] we ourselves are part of nature and therefore part of the mystery that we are trying to solve.” His fellow Nobel laureate and quantum theory founding father Niels Bohr defied the sentiment in his incisive distinction between subjective and objective reality, noting that religions have always addressed the former, while science addresses the latter, which is measurable and therefore knowable. Wolfgang Pauli, whose groundbreaking scientific ideas were greatly influenced by Bohr’s, concluded that the effort to reconcile science and religion “will always be full of pitfalls and one can fall down on both sides.”

It takes a mind of rare courage and insight to address this abiding question without falling into the most pernicious trap of all — that of artificial compatibilism; to take a lucid stance without fright of offense, then to explain the basis of that stance thoughtfully and sensitively, systematically dismantling every reflexive argument against it.

That is what Stephen Hawking (January 8, 1942–March 14, 2018) does in his final book, Brief Answers to the Big Questions (public library) — a collection of ten enormous questions Hawking was asked regularly throughout his life, by children and elders, by entrepreneurs and political leaders, by men and women young and old attending his prolific lectures and public appearances, with answers drawn from his extensive personal archive of correspondence, notes, drafts, interviews, and essays. The book — which was conceived during Hawking’s lifetime but finished only after his death with help from his family and academic colleagues, and proceeds from which benefit the Stephen Hawking Foundation and the Motor Neurone Disease Association — opens with the question that has bellowed in humanity’s chest since science first confronted superstition: Is there a God?

Hawking — whom many consider the greatest scientist since Einstein and whose residual stardust was interred between Darwin’s and Newton’s in Westminster Abbey — enlists his disarming deadpan humor in placing the query in a personal context, then uses the fulcrum of his magnificent mind to pivot into the serious answer to the universal question:

For centuries, it was believed that disabled people like me were living under a curse that was inflicted by God. Well, I suppose it’s possible that I’ve upset someone up there, but I prefer to think that everything can be explained another way, by the laws of nature. If you believe in science, like I do, you believe that there are certain laws that are always obeyed. If you like, you can say the laws are the work of God, but that is more a definition of God than a proof of his existence.

With an eye to the discovery, which began in antiquity and culminated with Kepler and Galileo, that “the heavens” are in fact a complex universe governed by discoverable and discernible physical laws, he builds upon his earlier reflections on the meaning of the universe and adds:

I believe that the discovery of these laws has been humankind’s greatest achievement, for it’s these laws of nature — as we now call them — that will tell us whether we need a god to explain the universe at all. The laws of nature are a description of how things actually work in the past, present and future. In tennis, the ball always goes exactly where they say it will. And there are many other laws at work here too. They govern everything that is going on, from how the energy of the shot is produced in the players’ muscles to the speed at which the grass grows beneath their feet. But what’s really important is that these physical laws, as well as being unchangeable, are universal. They apply not just to the flight of a ball, but to the motion of a planet, and everything else in the universe. Unlike laws made by humans, the laws of nature cannot be broken — that’s why they are so powerful and, when seen from a religious standpoint, controversial too.

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One could define God as the embodiment of the laws of nature. However, this is not what most people would think of as God. They mean a human-like being, with whom one can have a personal relationship. When you look at the vast size of the universe, and how insignificant and accidental human life is in it, that seems most implausible.

I use the word “God” in an impersonal sense, like Einstein did, for the laws of nature, so knowing the mind of God is knowing the laws of nature. My prediction is that we will know the mind of God by the end of this century.

But even with the laws of nature conceded, Hawking recognizes that their existence still leaves room for religions to lay claim to the grandest question — how the universe and its laws began. He addresses the question both plainly and profoundly:

I think the universe was spontaneously created out of nothing, according to the laws of science.

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Despite the complexity and variety of the universe, it turns out that to make one you need just three ingredients. Let’s imagine that we could list them in some kind of cosmic cookbook. So what are the three ingredients we need to cook up a universe? The first is matter — stuff that has mass. Matter is all around us, in the ground beneath our feet and out in space. Dust, rock, ice, liquids. Vast clouds of gas, massive spirals of stars, each containing billions of suns, stretching away for incredible distances.

The second thing you need is energy. Even if you’ve never thought about it, we all know what energy is. Something we encounter every day. Look up at the Sun and you can feel it on your face: energy produced by a star ninety-three million miles away. Energy permeates the universe, driving the processes that keep it a dynamic, endlessly changing place.

So we have matter and we have energy. The third thing we need to build a universe is space. Lots of space. You can call the universe many things — awesome, beautiful, violent — but one thing you can’t call it is cramped. Wherever we look we see space, more space and even more space. Stretching in all directions.

The instinctual question is where all the matter, energy, and space came from — a question we hadn’t been able to answer with more than mythological cosmogonies until the early twentieth century, when Einstein demonstrated that mass is a form of energy and energy a form of mass in what is now the best known equation in the history of the world: E=mc². This reduces the ingredients of the “cosmic cookbook” from three to two, distilling the question to where the space and energy originated. Generations of scientists built upon each other’s work to deliver the answer in the Big Bang model, which holds that in a single moment around 13.8 billion years ago, the entire universe, with all its space and energy, ballooned into being out of the nothingness that preceded it.

Half a century after Nabokov’s poetic admonition against common sense, Hawking echoes Carl Sagan’s observation that common sense can blind us to the realities of the universe and addresses this deeply counterintuitive notion of generating something out of nothing:

As I was growing up in England after the Second World War, it was a time of austerity. We were told that you never get something for nothing. But now, after a lifetime of work, I think that actually you can get a whole universe for free.

The great mystery at the heart of the Big Bang is to explain how an entire, fantastically enormous universe of space and energy can materialise out of nothing. The secret lies in one of the strangest facts about our cosmos. The laws of physics demand the existence of something called “negative energy.”

To help you get your head around this weird but crucial concept, let me draw on a simple analogy. Imagine a man wants to build a hill on a flat piece of land. The hill will represent the universe. To make this hill he digs a hole in the ground and uses that soil to dig his hill. But of course he’s not just making a hill — he’s also making a hole, in effect a negative version of the hill. The stuff that was in the hole has now become the hill, so it all perfectly balances out. This is the principle behind what happened at the beginning of the universe.

When the Big Bang produced a massive amount of positive energy, it simultaneously produced the same amount of negative energy. In this way, the positive and the negative add up to zero, always. It’s another law of nature.

So where is all this negative energy today? It’s in the third ingredient in our cosmic cookbook: it’s in space. This may sound odd, but according to the laws of nature concerning gravity and motion — laws that are among the oldest in science — space itself is a vast store of negative energy. Enough to ensure that everything adds up to zero.

I’ll admit that, unless mathematics is your thing, this is hard to grasp, but it’s true. The endless web of billions upon billions of galaxies, each pulling on each other by the force of gravity, acts like a giant storage device. The universe is like an enormous battery storing negative energy. The positive side of things — the mass and energy we see today — is like the hill. The corresponding hole, or negative side of things, is spread throughout space.

So what does this mean in our quest to find out if there is a God? It means that if the universe adds up to nothing, then you don’t need a God to create it. The universe is the ultimate free lunch.

This is where the wheels of our common-sense understanding screech to a frustrated halt — after all, in our daily lives, we can’t just manifest a cone of ice cream or a long-lost lover with the snap of our fingers. But on the subatomic stratum undergirding our physical reality, things work differently — particles pop up at random times in random places only to disappear again, governed by the laws of quantum mechanics, which seem downright mystical in their manifestation but are in fact discovered and calculable laws of the universe. Hawking explains:

Since we know the universe itself was once very small — perhaps smaller than a proton — this means something quite remarkable. It means the universe itself, in all its mind-boggling vastness and complexity, could simply have popped into existence without violating the known laws of nature. From that moment on, vast amounts of energy were released as space itself expanded — a place to store all the negative energy needed to balance the books. But of course the critical question is raised again: did God create the quantum laws that allowed the Big Bang to occur? In a nutshell, do we need a God to set it up so that the Big Bang could bang? I have no desire to offend anyone of faith, but I think science has a more compelling explanation than a divine creator.

Once again he illustrates this assault on our basic common-sense intuitions with that supreme lever of understanding, the analogy:

Imagine a river, flowing down a mountainside. What caused the river? Well, perhaps the rain that fell earlier in the mountains. But then, what caused the rain? A good answer would be the Sun, that shone down on the ocean and lifted water vapour up into the sky and made clouds. Okay, so what caused the Sun to shine? Well, if we look inside we see the process known as fusion, in which hydrogen atoms join to form helium, releasing vast quantities of energy in the process. So far so good. Where does the hydrogen come from? Answer: the Big Bang. But here’s the crucial bit. The laws of nature itself tell us that not only could the universe have popped into existence without any assistance, like a proton, and have required nothing in terms of energy, but also that it is possible that nothing caused the Big Bang. Nothing.

This explanation, Hawking points out, rests on the shoulders of Einstein’s groundbreaking relativity theory — that daring leap of the imaginative intellect, which furnished the staggering revelation that space and time are a single entity comprising the basic fabric of the universe. Hawking writes:

Something very wonderful happened to time at the instant of the Big Bang. Time itself began.

To understand this mind-boggling idea, consider a black hole floating in space. A typical black hole is a star so massive that it has collapsed in on itself. It’s so massive that not even light can escape its gravity, which is why it’s almost perfectly black. It’s gravitational pull is so powerful, it warps and distorts not only light but also time. To see how, imagine a clock is being sucked into it. As the clock gets closer and closer to the black hole, it begins to get slower and slower. Time itself begins to slow down. Now imagine the clock as it enters the black hole — well, assuming of course that it could withstand the extreme gravitational forces– it would actually stop. It stops not because it is broken, but because inside the black hole time itself doesn’t exist. And that’s exactly what happened at the start of the universe.

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As we travel back in time towards the moment of the Big Bang, the universe gets smaller and smaller and smaller, until it finally comes to a point where the whole universe is a space so small that it is in effect a single infinitesimally small, infinitesimally dense black hole. And just as with modern-day black holes, floating around in space, the laws of nature dictate something quite extraordinary. They tell us that here too time itself must come to a stop. You can’t get to a time before the Big Bang because there was no time before the Big Bang. We have finally found something that doesn’t have a cause, because there was no time for a cause to exist in. For me this means that there is no possibility of a creator, because there is no time for a creator to have existed in.

Hawking concludes with his most direct, personal answer to the universal question:

It’s my view that the simplest explanation is that there is no God. No one created the universe and no one directs our fate. This leads me to a profound realisation: there is probably no heaven and afterlife either. I think belief in an afterlife is just wishful thinking. There is no reliable evidence for it, and it flies in the face of everything we know in science. I think that when we die we return to dust. But there’s a sense in which we live on, in our influence, and in our genes that we pass on to our children. We have this one life to appreciate the grand design of the universe, and for that I am extremely grateful.

Rather than dispiriting, this lucid awareness of our ephemerality can be the wellspring of our noblest, most deeply spiritual and spiritualizing impulses — a catalyst for finding holiness in the richness of life itself, in the splendor of this peculiar and irreplaceable planet, rooted in the awareness that, in the poetic words of naturalist Sy Montgomery, “our world, and the worlds around and within it, is aflame with shades of brilliance we cannot fathom — and is far more vibrant, far more holy, than we could ever imagine.” Hawking channels this orientation of mind and spirit in a stirring passage from the book’s introduction:

One day, I hope we will know the answers to all these questions. But there are other challenges, other big questions on the planet which must be answered, and these will also need a new generation who are interested and engaged, and have an understanding of science. How will we feed an ever-growing population? Provide clean water, generate renewable energy, prevent and cure disease and slow down global climate change? I hope that science and technology will provide the answers to these questions, but it will take people, human beings with knowledge and understanding, to implement these solutions. Let us fight for every woman and every man to have the opportunity to live healthy, secure lives, full of opportunity and love. We are all time travellers, journeying together into the future. But let us work together to make that future a place we want to visit. Be brave, be curious, be determined, overcome the odds. It can be done.

Complement this particular portion of Hawking’s altogether magnificent Brief Answers to the Big Questions with Carl Sagan on science and mystery, Alan Lightman on nonreligious divinity in the known and the unknowable, and Buckminster Fuller’s scientific revision of “The Lord’s Prayer,” then revisit poet Marie Howe’s gorgeous tribute to Hawking.