There could have been nothing. It might have been easier. Instead there is something. The universe exists, and we are here to ask about it. Why?




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“Why is there something rather than nothing?” sounds so fundamental a question that it should have perplexed humanity since the dawn of philosophy.





Strangely, it hasn’t, or at least it has left no trace on early written literature. Aristotle said that philosophy begins with wonder, and earlier Greek philosophers did wonder what the world was made of. Thales thought its primal substance was water, Anaximenes air, Heraclitus fire.



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But they didn’t ask why anything was there at all. We find no one haunted by the specter of non-being until Gottfried Wilhelm Leibniz, who wrote in 1714, “The first question which we have a right to ask will be, ‘Why is there something rather than nothing?’ ” 



      
For some, the question is not really a question. It is more an expression of philosophical amazement — a way of saying “wow” in the face of existence.




       
Ludwig Wittgenstein described a feeling of awe that led him to use phrases like “How extraordinary that anything should exist,” but he decided it was better not to say such things. Martin Heidegger decided the other way, and made the Question of Being the foundation for his entire philosophy, becoming, as George Steiner described him, “the great master of astonishment, the man whose amazement before the blank fact that we are instead of not being, has put a radiant obstacle in the path of the obvious.”



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Other people have treated it as a real question, the kind that might have an answer. And some think they have actually found answers, though these tend to be so different that one can hardly believe they started with the same question.



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In “Why Does the World Exist?,” Jim Holt, an elegant and witty writer comfortably at home in the problem’s weird interzone between philosophy and scientific cosmology, sets out in search of such answers. He takes inspiration from readings of Heidegger and Sartre, and from something Martin Amis once said in a television interview: “We’re at least five Einsteins away from answering that question.” Holt, a frequent contributor to the Book Review, speculates that some of these Einsteins might be at work already. “If I could find one, or maybe two or three or even four of them, and then sort of arrange them in the right order,” he says amiably, “well, that would be an excellent quest.” In fact, he finds eight thinkers worthy of a chapter each, as well as some bit-players like a Zen Buddhist who answers the question by attempting to bop Holt on the head, koan style. The Zen angle ends there, and Holt is similarly unimpressed by the approaches of monotheistic religion. 



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So he travels to Paris, London, Oxford (several times), Pittsburgh and Austin, Tex., to meet the philosophers and cosmologists David Deutsch, Adolf Grünbaum, John Leslie, Derek Parfit, Roger Penrose, Richard Swinburne and Steven Weinberg. He also has a discussion with the philosophically inclined novelist John Updike. As he moves from one to the other, Holt learns of ever more extraordinary solutions, some almost mystical, yet rooted in solid reasoning.



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His first interlocutor, the philosopher Adolf Grünbaum, throws down a challenge: Why be astonished at being at all? To marvel at existence is to assume that nothingness is somehow more natural, more restful. But why? The ancients started with matter, not the void; perhaps nothingness is stranger than being.



       
Holt’s other conversations are with people who do marvel at being, but they also confirm Grünbaum’s point about the puzzling nature of nothingness. It is all very well to say the universe started with a Big Bang, but how? Did it burst out like “a party girl jumping out of a cake,” as Fred Hoyle put it? But how can one even speak of cakes, or of “bursting out,” when there is no pre-Bang time or space from which to burst? As Holt says, we tend to think of the start of the universe by analogy with a concert, where we sit fiddling with our programs until the music begins. But there is no tuning-up, no fiddling. It’s hard to visualize nothingness, though Holt quotes a beautiful definition by the physicist Alex Vilenkin: “a closed spherical spacetime of zero radius.” Try jumping out of that.



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No wonder the philosopher Robert Nozick said that “someone who proposes a nonstrange answer shows he didn’t understand the question.” Nozick’s own hypotheses were certainly strange. One was that the primal nothingness might have been so annihilating that it annihilated itself, thus producing being. This echoes a much-mocked line of Heidegger’s: “nothing noths” (“Das Nichts nichtet”).



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Silly as it sounds, this captures the sheer uncanniness of the Big Bang — and, as Heidegger said, the anxiety we feel in the thought of “nothing” brings us face to face with Being itself.


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Several of Holt’s cosmologists explore the possibility of there being universes “as plentiful as blackberries” (C. S. Peirce’s phrase). Universes may be popping into existence right now: each moment may generate billions of new ones. Perhaps all possible universes have existed from the start, including one that contains nothing. Perhaps everything exists because of fluctuations in quantum particles, or because an initial zero separated itself into +1 and -1, forming matter and antimatter.




Perhaps only mathematical entities are real, and our physical world is an “outcropping” of mathematics. Could the world be an outcropping of consciousness? Does all nature have a subjectivity of its own? Or is the universe a device for producing goodness?There is no way to do justice to any of these theories in a brief review, but Holt traces the reasoning behind each one with care and clarity — such clarity that each idea seems resoundingly sensible even as it turns one’s brain to a soup of incredulity.





He is an urbane guide, involving us in his personal adventures. We join him for a weekend sipping claret and reading Parfit in a bathtub at the Athenaeum Club in London. He takes us to Paris for no good reason except to sit in the Café de Flore with a volume of Hegel. We stay with him through the death of his dog, and — movingly — even attend his mother’s deathbed, where she undergoes “the infinitesimal transition from being to nothingness.”




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Holt reminds us that no exploration of being — especially human being — can be separated from the human who undertakes it, complete with character and the play of moods. Updike felt that the universe had “a color, a quiet but tireless goodness that things at rest, like a brick wall or a small stone, seem to affirm.”




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Surely this was a mood, even a quirk of biochemistry, but it opens a perspective on the universe, too. The question of being itself, as Updike and Holt agree, can seem profound in one mood, vacuous in another.



One evening in Oxford, Holt enjoys a fine meal and bottle of Australian shiraz, then strolls around feeling “a diffuse sense of contentment.” This is one beginning for philosophy; Heidegger’s “anxiety” is another (and perhaps Heidegger should have drunk more shiraz). The rest requires only a willingness to think — and I can imagine few more enjoyable ways of thinking than to read this book.



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Sarah Bakewell is the author of “How to Live: Or, A Life of Montaigne in One Question and Twenty Attempts at an Answer.”