One of the quotations at the start of Jim Holt’s enticing Why Does the World Exist? is a warning from Queen Victoria to one of her granddaughters, to the effect that one really shouldn’t read books like this. “To try and find out the reason for everything is very dangerous,” wrote the queen to Princess Victoria of Hesse, in 1883. It leads to “nothing but disappointment and dissatisfaction, unsettling your mind and in the end making you miserable.”
Have we got any closer since Victorian times to being able to find the reason for everything? In one sense, yes: for Queen Victoria, a big bang would just have been something you berated the servants about. Now we have modern cosmology, and thus at least some of the story of how the universe started. So the quest for the ultimate origin of things is not quite as disappointing as it once was. In another sense, though, it is. If you’re looking for the reason for literally everything, then it is not clear that any scientific advance can give you what you want, and dissatisfaction threatens now as much as it did back in the 1880s. The reason for this is simple. Every scientific explanation takes something for granted—some laws of nature, for example, or some equations, or a set of initial conditions. But what, in turn, explains them? If anything did, then it, in turn, would require explanation, too.
Even people who postulate a creative God usually acknowledge that his existence shifts the big question rather than resolving it. Why does God exist, and how did he make the world? It may be some consolation to the religious to realise that science, too, is constitutionally incapable of bringing all questioning to an end. Neither religion nor science can deliver a final answer to the puzzle at the heart of Jim Holt’s book—Why is there something rather than nothing?—because God is something, and so are scientific laws.
It was a German philosopher, Gottfried Leibniz, who, in the early eighteenth century, first posed what is sometimes called the ultimate metaphysical question in this way. One rare virtue of Holt’s book stems from the fact that its author is comfortably at home among philosophers as well as among physicists. Since philosophy and physics intertwine at the far reaches of cosmology, this makes him a much more satisfying guide than most. Another virtue comes from the exploratory style of the book, which is built around a series of interviews with physicists, philosophers, some rather unclassifiable thinkers who straddle the two disciplines, and one novelist (the late John Updike). The intellectual curiosity that animates Mr Holt’s arguments with his interlocutors, and his musings on the experience after each interview, make this “existential detective story”, as he calls it, rather livelier than one has any right to expect from a whodunnit in which you never actually discover who did.
Like a 13th or 14th century scholastic, Mr Holt (who is a member of my philosophy group) finds himself regularly shuttling between Oxford and Paris in the search for enlightenment. Paris, for him, usually means the Café de Flore, on the boulevard Saint-Germain, where he conjures the spirits of Jean-Paul Sartre, Descartes, Leibniz, and Hegel. Gastronomically and aesthetically, he has a better time in Paris; but it is in Oxford that most of his ten interviewees live.
His first Oxford encounter is with Richard Swinburne, a philosopher and theologian, who is, unusually, convinced by empirical arguments in favour of a traditional Christian worldview. For Swinburne, there are physical signs that a God made everything else, and that is that. The next Oxford man is David Deutsch, a physicist and pioneer of the theory of quantum computing, who believes in innumerable parallel worlds, but does not think it is possible for physics to explain why any of them are there. The next Oxonian is Sir Roger Penrose, a British mathematician, who not only believes in a timeless realm of mathematical truths, but is inclined to think that it somehow gives rise to the physical realm. This understandably baffles Holt, who emerges dazed from Penrose’s “penthouse world of Platonic ideas and, after a quick elevator descent, reentered the ephemeral world of sensuous appearances below,” thus recalling Dante escape back into the open air in the last lines of his Inferno. The last Oxford thinker is a philosopher, Derek Parfit, whose approach to the problem of existence is so abstract and formalistic that it amounts to a type of mathematics, albeit without numbers. Parfit’s thought seems to stimulate Mr Holt more than that of any of his other subjects, and he includes an epistolary chapter comprising a letter to Parfit in which he tries to extend his ideas for him. The philosopher does not offer any comments in return.
Four more interviews take place in various parts of North America, of which the liveliest is in Pittsburgh with Adolf Grünbaum, an irrepressible philosopher of science of almost 90 years of age, who does not think that existence presents any sort of mystery, and whose driving terrifies Mr Holt. At Stanford, he talks to Andrei Linde, a Russian-born physicist, whose theory of “chaotic inflation” explains how relatively easy it would be to make a galaxy, which leads Holt to reflect that God might be a not especially competent hacker. Near Boston, he meets the Ukrainian-born cosmologist, Alex Vilenkin, who has done perhaps more than anyone to try and explain how a universe could pop out of a state of absolute nothingness. On the west coast of Canada, Holt meets a highly original British-born philosopher-cosmologist, John Leslie, who maintains that the existence of the universe is a morally good thing, and that this fact explains why it exists.
It has sometimes been argued that “Why is there something rather than nothing?” is such a bizarre question that only an unconventional answer will suffice. But Leslie’s solution appears to be even more mysterious than the puzzle. At any rate, it invites the complaint that Byron made to Wordsworth: “I wish he would explain his Explanation.” Towards the end of his journey, Holt confides that sometimes the thought that there is something rather than nothing strikes him as deeply mysterious, and sometimes as perfectly vacuous. (The same is true, as he reports in a chapter surveying theories of the self, of the thought that the world miraculously includes me.) This seems to be one mark of the most perplexing philosophical problems: they zoom uncontrollably in and out of focus. It’s also sometimes hard to resist the idea that, because it is inconceivable that anything could count as a complete answer to the question of why there is something rather than nothing, anything that masqueraded as one would be disappointing.